低损耗BZN/BST介电薄膜及微波变容管技术研究
|
摘要
微波调谐器件通过调控微波信号的频率、相位或幅度，能够简化电路、降低元器件数目、提高系统性能，是现代通讯系统的发展趋势。基于介电薄膜材料的介质变容管技术具有响应速度快、功率容量大、功耗小、成本低和易集成的优点，被认为是微波调谐器件的重要发展方向。目前研究较集中的介电可调材料是BaxSr1xTiO3（BST）薄膜材料，其特点是介电调谐率大、但介电损耗较高，不能满足高性能微波调谐器件的应用要求。近些年发现的烧绿石结构Bi1.5Zn1.0Nb1.5O7（BZN）薄膜材料介电损耗很低，但介电调谐率较小。本论文将高可调的BST薄膜材料与低损耗的BZN薄膜材料复合，研制兼具低损耗和高调谐率的BZN/BST复合薄膜，开展高性能BZN/BST薄膜变容管技术研究，探索介质薄膜变容管在微波调谐器件的应用研究。主要内容和结论如下：
1.采用射频磁控溅射法制备BZN/BST复合薄膜，研究了BZN/BST复合薄膜的介电性能。从电介质串联理论出发，建立了双层复合可调介质薄膜介电性能与结构关系参数模型，通过优化控制BZN/BST复合薄膜的各层厚度比，获得了具有低损耗、高可调的BZN/BST复合薄膜。研制的BZN/BST复合薄膜的介电损耗为~0.78%，在偏置电场1MV/cm下的介电调谐率为~46%。
2.研究了BZN/BST复合薄膜的界面效应和漏电特性。研究结果表明，BZN薄膜的费米能级在带隙中比BST薄膜的费米能级深，在BZN-BST界面处形成的界面势垒提高了BZN/BST复合薄膜的P-F发射（Poole-Frenkel emission）漏电机制的开启电场，从而降低了薄膜的泄漏电流。另外，由于BZN薄膜的引入增大了介质薄膜与上电极接触面的势垒高度，减小了肖特基发射电流，从而也有利于降低复合薄膜的泄漏电流。因此， BZN/BST复合薄膜具有低损耗、高可调和低漏电流的特点。
3.对BZN/BST介质薄膜变容管进行了高Q值结构设计研究，提出了一种新的平板型变容管多指电极结构。多指电极结构是多电容并联结构，与单电容结构相比具有较高的Q值，同时还具有更好的可靠性，特别适合较大容值的介质薄膜电容设计。
4.采用微细加工技术研制了BZN/BST薄膜变容管。利用反转光刻胶优化了电极的图形化工艺；以HF酸为刻蚀剂、NH4F为络合剂、HNO3为助溶剂、去离子水为稀释剂的刻蚀液能很好地刻蚀介质薄膜，解决了BZN/BST复合薄膜的图形化问题。
5.研究了BZN/BST介质薄膜变容管的高频介电性能。结果表明，研制的BZN/BST介质薄膜变容管在高频下具有较高的Q值，在100MHz时Q值仍达到150，变容管的电容值及调谐率具有良好的频率稳定性和温度稳定性。随频率的升高，变容管Q值主要由电极损耗决定，其Q值随频率的升高而下降。采用高电导率电极、加厚电极的方法能够减小电极损耗，从而提高变容管的高频Q值。将研制的BZN/BST薄膜变容管用于工作频率为445MHz的移相器中进行应用验证，结果表明移相器的最大插入损耗为~0.9dB，显著优于半导体变容管。
6.研制了基于BZN/BST薄膜的采用周期性负载电容结构的X波段传输型移相器。为了改善阻抗匹配，将变容管负载在单节传输线两端，减小了移相器的回波损耗和插入损耗。研制的BZN/BST薄膜移相器在12GHz时的回波损耗优于-13dB，最大插入损耗为-4dB，能够提供0至65°连续变化的相移量。
Microwave tunable devices can improve the system performances and reduce thenumber of components by controlling the frequency, phase and amplitude of microwavesignal, thus becoming the development tendency of modern communication systems.Among the electric tuning technologies, dielectric thin film varactors have severalproperties that make them attractive for microwave tunable applicaions including fastresponse speed, high power handling capability, relatively low loss, and low cost.Therefore, it is very important to investigate the thin film varactor technologies. Most ofthe literature on microwave applications of tunable dielectrics has focused on theferroelectric BaxSr1-xTiO3(BST) thin films. BST thin films indicate large dielectrictunability whereas the loss of these films is relatively high, e.g. tan δ>0.01forBa0.5Sr0.5TiO3thin films at room temperature. Recently, cubic pyrochloreBi1.5Zn1.0Nb1.5O7(BZN) thin films have gained a great deal of attention because of theirvery low dielectric loss and a certain dielectric tunability. However, the tunability ofthese films is relatively low and it requires very high electric fields to achieve a hightunability. In this dissertation, BZN/BST bilayered thin films were investigated to utilizethe optimum combination of the high tunability of BST and the low loss of BZN, andthe low loss BZN/BST thin film varactor technologies were developed.
The BZN/BST composite thin films were prepared on Pt/Ti-coated sapphiresubstrates by radio frequency magnetron sputtering. Based on the dielectric connectiontheory, a model for the relationship between dielectric properties and constructionparameters of bilayered thin films was established. Through optimum control thethickness ratio of bilayered thin films, BZN/BST composite films with optimumcombination of low loss and high tunability were obtained. The dielectric loss of thesefilms was~0.78%, and the relative tunability was~46%at an electric filed of1MV/cm.
The interfacial effects of BZN/BST bilayered thin films were investigated. TheFermi level of BZN films was deeper in the band gap than that of BST films, and thus apotential barrier was established at the BZN-BST interface. The electrons ejected from trapcenters in BST need higher energy to overcome the potential barrier for transporting into conduction band of BZN. This resulted in an increase of the threshold electric field of PFemission for BZN/BST at positive biases, and accordingly the currents in BZN/BSTbilayered films were decreased. In addition the barrier height of top contact was increased bythe insertion of a BZN layer between BST and top Pt-electrodes, resulting in a current reductionof BZN/BST composite thin films.
It was proposed a capacitor construction of several capacitors in parallel toimprove the device Q-factor. Capacitors with new construction showed higher Q-factorthan that of conventional parallel capacitors, and it was also helpful to improve thereliability of the devices, particular in the large capacitance situation.
The electrodes were patterned by a lift-off process. The mixed liquor compositedof HF as etching liquor, NH4F as complex catalyst, HNO3as cosolvent, and dilutiondeionized water perfectly etched the dielectric films.
The dielectric properties of BZN/BST thin film varactors were investigated. Thevaractors indicated a high Q-factor of~150at frequency of100MHz andfrequency-independent capacitance and tunability. The Q-factor of varactors wasrestricted by the conductive loss of electrodes at high frequencies, and thus decreased asfrequency increased. Incorporate electrodes with higher conductivity and largerthickness would decrease the conductive loss, and hence improve the high Q-factor ofthe BZN/BST varactors. The phase shifter employing BZN/BST varactors exhibitedlower insertion loss than that of employing semiconductor diodes at designed frequencyof445MHz, demonstrating the potential of BZN/BST varactors for RF applications.
At last, the demonstration of an X-band distributed phase shifter implemented withBZN/BST thin films was presented. In the form of two identical varactors loading atboth sides of the unit line exhibited better impedance matching and low insertion loss ofthe phase shifter of a transmission line periodically loaded with varactors. The returnloss of the phase shifter was better than-13dB at12GHz, the maximum insertion losswas-4dB and the differential phase was continuously variable from0to65°.
1.采用射频磁控溅射法制备BZN/BST复合薄膜，研究了BZN/BST复合薄膜的介电性能。从电介质串联理论出发，建立了双层复合可调介质薄膜介电性能与结构关系参数模型，通过优化控制BZN/BST复合薄膜的各层厚度比，获得了具有低损耗、高可调的BZN/BST复合薄膜。研制的BZN/BST复合薄膜的介电损耗为~0.78%，在偏置电场1MV/cm下的介电调谐率为~46%。
2.研究了BZN/BST复合薄膜的界面效应和漏电特性。研究结果表明，BZN薄膜的费米能级在带隙中比BST薄膜的费米能级深，在BZN-BST界面处形成的界面势垒提高了BZN/BST复合薄膜的P-F发射（Poole-Frenkel emission）漏电机制的开启电场，从而降低了薄膜的泄漏电流。另外，由于BZN薄膜的引入增大了介质薄膜与上电极接触面的势垒高度，减小了肖特基发射电流，从而也有利于降低复合薄膜的泄漏电流。因此， BZN/BST复合薄膜具有低损耗、高可调和低漏电流的特点。
3.对BZN/BST介质薄膜变容管进行了高Q值结构设计研究，提出了一种新的平板型变容管多指电极结构。多指电极结构是多电容并联结构，与单电容结构相比具有较高的Q值，同时还具有更好的可靠性，特别适合较大容值的介质薄膜电容设计。
4.采用微细加工技术研制了BZN/BST薄膜变容管。利用反转光刻胶优化了电极的图形化工艺；以HF酸为刻蚀剂、NH4F为络合剂、HNO3为助溶剂、去离子水为稀释剂的刻蚀液能很好地刻蚀介质薄膜，解决了BZN/BST复合薄膜的图形化问题。
5.研究了BZN/BST介质薄膜变容管的高频介电性能。结果表明，研制的BZN/BST介质薄膜变容管在高频下具有较高的Q值，在100MHz时Q值仍达到150，变容管的电容值及调谐率具有良好的频率稳定性和温度稳定性。随频率的升高，变容管Q值主要由电极损耗决定，其Q值随频率的升高而下降。采用高电导率电极、加厚电极的方法能够减小电极损耗，从而提高变容管的高频Q值。将研制的BZN/BST薄膜变容管用于工作频率为445MHz的移相器中进行应用验证，结果表明移相器的最大插入损耗为~0.9dB，显著优于半导体变容管。
6.研制了基于BZN/BST薄膜的采用周期性负载电容结构的X波段传输型移相器。为了改善阻抗匹配，将变容管负载在单节传输线两端，减小了移相器的回波损耗和插入损耗。研制的BZN/BST薄膜移相器在12GHz时的回波损耗优于-13dB，最大插入损耗为-4dB，能够提供0至65°连续变化的相移量。
Microwave tunable devices can improve the system performances and reduce thenumber of components by controlling the frequency, phase and amplitude of microwavesignal, thus becoming the development tendency of modern communication systems.Among the electric tuning technologies, dielectric thin film varactors have severalproperties that make them attractive for microwave tunable applicaions including fastresponse speed, high power handling capability, relatively low loss, and low cost.Therefore, it is very important to investigate the thin film varactor technologies. Most ofthe literature on microwave applications of tunable dielectrics has focused on theferroelectric BaxSr1-xTiO3(BST) thin films. BST thin films indicate large dielectrictunability whereas the loss of these films is relatively high, e.g. tan δ>0.01forBa0.5Sr0.5TiO3thin films at room temperature. Recently, cubic pyrochloreBi1.5Zn1.0Nb1.5O7(BZN) thin films have gained a great deal of attention because of theirvery low dielectric loss and a certain dielectric tunability. However, the tunability ofthese films is relatively low and it requires very high electric fields to achieve a hightunability. In this dissertation, BZN/BST bilayered thin films were investigated to utilizethe optimum combination of the high tunability of BST and the low loss of BZN, andthe low loss BZN/BST thin film varactor technologies were developed.
The BZN/BST composite thin films were prepared on Pt/Ti-coated sapphiresubstrates by radio frequency magnetron sputtering. Based on the dielectric connectiontheory, a model for the relationship between dielectric properties and constructionparameters of bilayered thin films was established. Through optimum control thethickness ratio of bilayered thin films, BZN/BST composite films with optimumcombination of low loss and high tunability were obtained. The dielectric loss of thesefilms was~0.78%, and the relative tunability was~46%at an electric filed of1MV/cm.
The interfacial effects of BZN/BST bilayered thin films were investigated. TheFermi level of BZN films was deeper in the band gap than that of BST films, and thus apotential barrier was established at the BZN-BST interface. The electrons ejected from trapcenters in BST need higher energy to overcome the potential barrier for transporting into conduction band of BZN. This resulted in an increase of the threshold electric field of PFemission for BZN/BST at positive biases, and accordingly the currents in BZN/BSTbilayered films were decreased. In addition the barrier height of top contact was increased bythe insertion of a BZN layer between BST and top Pt-electrodes, resulting in a current reductionof BZN/BST composite thin films.
It was proposed a capacitor construction of several capacitors in parallel toimprove the device Q-factor. Capacitors with new construction showed higher Q-factorthan that of conventional parallel capacitors, and it was also helpful to improve thereliability of the devices, particular in the large capacitance situation.
The electrodes were patterned by a lift-off process. The mixed liquor compositedof HF as etching liquor, NH4F as complex catalyst, HNO3as cosolvent, and dilutiondeionized water perfectly etched the dielectric films.
The dielectric properties of BZN/BST thin film varactors were investigated. Thevaractors indicated a high Q-factor of~150at frequency of100MHz andfrequency-independent capacitance and tunability. The Q-factor of varactors wasrestricted by the conductive loss of electrodes at high frequencies, and thus decreased asfrequency increased. Incorporate electrodes with higher conductivity and largerthickness would decrease the conductive loss, and hence improve the high Q-factor ofthe BZN/BST varactors. The phase shifter employing BZN/BST varactors exhibitedlower insertion loss than that of employing semiconductor diodes at designed frequencyof445MHz, demonstrating the potential of BZN/BST varactors for RF applications.
At last, the demonstration of an X-band distributed phase shifter implemented withBZN/BST thin films was presented. In the form of two identical varactors loading atboth sides of the unit line exhibited better impedance matching and low insertion loss ofthe phase shifter of a transmission line periodically loaded with varactors. The returnloss of the phase shifter was better than-13dB at12GHz, the maximum insertion losswas-4dB and the differential phase was continuously variable from0to65°.
引文
[1] J. F. White. High power p-I-n diode controlled, microwave transmission phase shifters[J]. IEEETrans. Microw. Theory Tech.,1965,13(2):233-242
[2] K. M. Johnson. Microwave varactor tuned transistor oscillator design[J]. IEEE Trans. Microw.Theory Tech.,1966,14(11):564-572
[3] L. Lin, C. Nguyen, R. T. Howe, et al. Micro electromechanical filters for signal processing[C].Proc. IEEE Micro. Electro. Mech. Syst. Workshop, Travemuende, Ger,1992,226-231
[4] F. Reggia, E. G. Spencer. A new technique in ferrite phase shifting for beam scanning ofmicrowave antennas[J]. Proc. IRE,1957,45(11):1510-1517
[5] P. Bao, T. J. Jackson, X. Wang, et al. Barium strontium titanate thin film varactors forroom-temperature microwave device applications[J]. J. Phys. D: Appl. Phys.,2008,41(6):063001
[6] A. K. Tagantsev, V. O. Sherman, K. F. Astafiev, et al. Ferroelectric materials for microwavetunable applications[J]. J. Electroceramics,2003,11(1-2):5-66
[7] N. Setter, D. Damjanovic, L. Eng, et al. Ferroelectric thin films: Review of materials, properties,and applications[J]. J. Appl. Phys.,2006,100(5):051606
[8] S. S. Gevorgian, E. L. Kollberg. Do we really need ferroelectrics in paraelectric phase only inelectrically controlled microwave devices?[J]. IEEE Trans. Microw. Theory Tech.,2001,49(11):2117-2124
[9] M. D. Domenico, D. A. Johnson, R. H. Pantell. Ferroelectric harmonic generator and thelarge-signal microwave characteristics of a ferroelectric ceramic[J]. J. Appl. Phys.,1962,33(5):1697-1706
[10] W. Ren, S. Trolier-McKinstry, C. A. Randall, et al. Bismuth zinc niobate pyrochlore dielectricthin films for capacitive applications[J]. J. Appl. Phys.,2001,89(1):767-774
[11] W. Fu, H. Wang, L. Cao, et al. Bi1.5Zn1.0Nb1.5O7/Mn-doped Ba0.6Sr0.4TiO3heterolayered thinfilms with enhanced tunable performance[J]. Appl. Phys. Lett.,2008,92(18):182910
[12] S. Wang. Preparation and characterization of ferroelectric thin films for tunable and pyroelectricapplications[D]. Singapore: National University of Singapore,2011,12
[13]黄静.钙钛矿结构微波陶瓷介电机理的研究[D].武汉:华中科技大学,2004,68-78
[14] J. Im, O. Auciello, P. K. Baumann, et al. Composition-control of magnetron-sputter-deposited(BaxSr1–x)Ti1+yO3+zthin films for voltage tunable devices[J]. Appl. Phys. Lett.,2000,76(5):625-627
[15] N. K. Pervez, P. J. Hansen, R. A. York. Optimization of high tunability barium strontiumtitanate thin films grown by rf magnetron sputtering[C]. IEEE Int. Symp. Appl. Ferroelectr.,Montreal, Canada,2005,278-280
[16] P. Padmini, T. R. Taylor, M. J. Lefevre, et al. Realization of high tunability barium strontiumtitanate thin films grown by rf magnetron sputtering[J]. Appl. Phys. Lett.,1999,75(20):3186-3188
[17] H. S. Kim, T. S. Hyum, H. G. Kim, et al. Orientation effect on microwave dielectric propertiesof Si-integrated Ba0.6Sr0.4TiO3thin films for frequency agile devices[J]. Appl. Phys. Lett.,2006,89(5):052902
[18] S. E. Moon, E. K. Kim, M. H. Kwak, et al. Orientation dependent microwave dielectricproperties of ferroelectric Ba1–xSrxTiO3thin films[J]. Appl. Phys. Lett.,2003,83(11):2166-2168
[19] W. Chang, J. M. Pond, S. W. Kirchoefer, et al. Strain-induced anisotropy in microwavedielectric properties of (Ba, Sr) TiO3thin films with directly applied uniaxial <100> stress[J].Appl. Phys. Lett.,2005,87(24):242904
[20] S. Anuranjan, D. Kumar, K. Rajiv. LaNiO3as contact material for (Ba, Sr) TiO3dielectric thinfilms[J]. Electrochem. Solid-State Lett.,1999,2(6):294-296
[21] G. Akcay, I. B. Misirlioglu, S. P. Alpay. Dielectric and pyroelectric properties of bariumstrontium titanate films on orthorhombic substrates with (110)//(100) epitaxy[J]. J. Appl. Phys.,2007,101(10):104110
[22] Y. Tomoaki, O. S. Vladimir, N. Andreas. Epitaxial/amorphous Ba0.3Sr0.7TiO3film compositestructure for tunable applications[J]. Appl. Phys. Lett.,2006,89(3):032905
[23] H. W. Wang, S. W. Ni, K. C. Lee. Enhanced tunability and electrical properties of bariumstrontium titanate thin films by gold doping in grains[J]. Appl. Phys. Lett.,2004,84(15):2874-2876
[24] B. H. Park, E. J. Peterson, Q. X. Jia. Effects of very thin strain layers on dielectric propertiesof epitaxial Ba0.6Sr0.4TiO3films[J]. Appl. Phys. Lett.,2001,78(4):533-535
[25] S. Hyun, J. H. Lee, S. S. Kim, et al. Anisotropic tuning behavior in epitaxial Ba0.5Sr0.5TiO3thinfilms[J]. Appl. Phys. Lett.,2000,77(19):3084-3086
[26] M. Jain, S. B. Majumder, R. S. Katiyar, et al. Improvement in electrical characteristics ofgraded manganese doped barium strontium titanate thin films[J]. Appl. Phys. Lett.,2003,82(12):1911-1913
[27] E. Ngo, P. C. Joshi, M. W. Cole, et al. Electrophoretic deposition of pure and MgO-modifiedBa0.6Sr0.4TiO3thick films for tunable microwave devices[J]. Appl. Phys. Lett.,2001,79(2):248-250
[28] S. Y. Lee, T. Y. Tseng. Electrical and dielectric behavior of MgO doped Ba0.7Sr0.3TiO3thin filmson Al2O3substrate[J]. Appl. Phys. Lett.,2002,80(10):1797-1799
[29] P. C. Joshia, M. W. Cole. Mg doped Ba0.6Sr0.4TiO3thin films for tunable microwaveapplications[J]. Appl. Phys. Lett.,2000,77(2):289-291
[30] M. W. Cole, W. D. Nothwang, C. Hubbard, et al. Low dielectric loss and enhanced tunability ofBa0.6Sr0.4TiO3based thin films via material compositional design and optimized film processingmethods[J]. J. Appl. Phys.,2003,93(11):9218-9225
[31] X. Liang, W. Wu, Z. Meng, et al. Dielectric and tunable characteristics of barium strontiumtitanate modified with Al2O3addition[J]. Mater. Sci. Eng. B,2003,99(1-3):366-369
[32] K. B. Chong, L. B. Kong, L. Chen, et al. Improvement of dielectric loss tangent of Al2O3dopedBa0.5Sr0.5TiO3thin films for tunable microwave devices[J]. J. Appl. Phys.,2004,95(3):1416-1419
[33] M. Lorenz, H. Hochmuth, M. Schallner, et al. Dielectric properties of Fe doped BaxSr1-xTiO3thin films on polycrystalline subst rates at temperatures between-35and+85℃[J].Solid-StateElectron.,2003,47(12):2199-2203
[34] J. Gong, J. Cheng, W. Zhu, et al. Improvement in dielectric and tunable properties of Fe-dopedBa0.6Sr0.4TiO3thin films grown by pulsed-laser deposition[J]. IEEE Trans. Ultrason. Ferroelectr.Freq. Control,2007,54(12):2579-2582
[35] K. T. Kang, M. H. Lim, H. G. Kim, et al. Mn-doped Ba0.6Sr0.4TiO3high-K gate dielectrics forlow voltage organic transistor on polymer substrate[J]. Appl. Phys. Lett.,2005,87(24):242908
[36] X. H. Zhu, D. N. Zheng, W. Peng, et al. Enhanced dielectric properties of Mn dopeBa0.6Sr0.4TiO3thin films fabricated by pulsed laser deposition[J]. Mater. Lett.,2006,60(9-10):1224-1228
[37] K. H. Ahn, S. Baik. Significant suppression of leakage current in (Ba, Sr) TiO3thin films by Nior Mn doping[J]. J. Appl. Phys.,2002,92(5):2651-2654
[38] H. Seo, Y. B. Kim, G. Lucovsky, et al. Enhanced leakage current properties of Ni-dopedBa0.6Sr0.4TiO3thin films driven by modified band edge state[J]. J. Appl. Phys.,2010,107(2):024109
[39] J. K. Kim, S. S. Kim, W. J. Kim, et al. Improved ferroelectric properties of Cr-dopedBa0.7Sr0.3TiO3thin films prepared by wet chemical deposition[J]. Mater. Lett.,2006,60(19):2322-2325
[40] H. S. Kim, H. G. Kim, I. D. Kim, et al. High-tunability and low-microwave-loss Ba0.6Sr0.4TiO3thin films grown on high-resistivity Si substrates using TiO2buffer layers[J]. Appl. Phys. Lett.,2005,87(21):212903
[41] Y. H. Gao, J. H. Ma, T. X. Li, et al. Improved dielectric and electrical behaviour oflow-temperature deposited (Ba0.6Sr0.4)TiO3films by thin SrTiO3buffer layer[J]. J. Phys. D:Appl. Phys.,2008,41(8):085305
[42] W. Zhu, J. Cheng, S. Yu, et al. Enhanced tunable properties of Ba0.6Sr0.4TiO3thin films grownon Pt/Ti/SiO2/Si substrates using MgO buffer layers[J]. Appl. Phys. Lett.,2007,90(3):032907
[43] N. Xiong, S. Jiang, Y. Li, et al. Dielectric properties of Ba0.5Sr0.5TiO3/SiN bilayered thin filmsgrown on Pt-coated sapphire substrates[J]. Appl. Phys. Lett.,2008,93(23):232905
[44] Y. Liu, A.S. Nagra, E.G. Erker, et al. BaSrTiO3interdigitated capacitors for distributed phaseshifter applications[J]. IEEE Microw. Guided Wave Lett.,2000,10(11):448-450
[45] B. Acikel, Y. Liu, A. S. Nagra, et al. Phase shifters using (Ba, Sr)TiO3thin films on sapphireand glass substrate[C]. IEEE MTT S Int. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1191-1194
[46] I. P. Koutsaroff, T. Bernacki, M. Zelner, et al. Microwave properties of parallel plate capacitorsbased on (Ba, Sr)TiO3thin films grown on SiO2/Al2O3substrates[C]. Mat. Res. Soc. Symp.Proc. Boston, MA, United States,2003,784,319-325
[47] A. Vorobiev, P. Rundqvist, K. Khamchane, et al. Silicon substrate integrated high Q-factorparallel-plate ferroelectric varactors for microwave/millimeterwave applications[J]. Appl. Phys.Lett.,2003,83(15):3144-3146
[48] E. G. Erker, A. S. Nagra, Y. Liu, et al. Monolithic Ka-band phase shifter using voltage tunableBaSrTiO3parallel plate capacitors[J]. IEEE Microw. Guided Wave Lett.,2000,10(1):10-12
[49] B. Acikel, T. R. Taylor, P. J. Hansen, et al. A new high performance phase shifter usingBaxSr1-xTiO3thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2002,12(7):237-239
[50] A. Mahmud, T. S. Kalkur, A. Jamil, et al. A1-GHz active phase shifter with a ferroelectricvaractor[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(5):261-263
[51] Z. Y. Zhao, X. Y. Wang, K. Choi, et al. Ferroelectric phase shifters at20and30GHz[J]. IEEETrans. Microw. Theory Tech.,2007,55(2):430-437
[52] G. Vélu, K. Blary, L. Burgnies, et al. A360°BST phase shifter with moderate bias voltage at30GHz[J]. IEEE Trans. Microw. Theory Tech.,2007,55(2):438-444
[53] K. B. Kim, T. S. Yun, J. C. Lee, et al. Integration of coplanar (Ba, Sr)TiO3microwave phaseshifters onto Si wafers using TiO2buffer layers[J]. IEEE Trans. Ultrason. Ferroelectr. Freq.Control,2006,53(3):518-524
[54] S. Sheng, P. Wang, X. Chen, et al. Two paralleled Ba0.25Sr0.75TiO3ferroelectric varactors seriesconnected coplanar waveguide microwave phase shifter[J]. J. Appl. Phys.,2009,105(11):114509
[55] Q. D. Meng, X. Q. Zhang, F. Li, et al. An impedance matched phase shifter using BaSrTiO3thinfilm[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(6):345-347
[56] H. Chen, C. Yang, J. Zhang, et al. High performance distributed CPW phase shifters withetched BST thin films on Ф3’’ LaAlO3substrates[J]. Solid State Sci.,2012,14(1):117-120
[57] J. Nath, D. Ghosh, J.-P. Maria, et al. An electronically tunable microstrip bandpass filter usingthin-film barium-strontium-titanate (BST) varactors[J]. IEEE Trans. Microw. Theory Tech.,2005,53(9):2707-2712
[58] X. P. Liang, Y. Zhu. Hybrid resonator microstrip line electrically tunable filter[C]. IEEE MTT SInt. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1457-1460
[59] J. Xu, X. P. Liang, S. Khosro. Full wave analysis and design of RF tunable filters[C]. IEEEMTT S Int. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1449-1452
[60] A. Jamil, T. S. Kalkur, N. Cramer. Tunable ferroelectric capacitor-based voltage-controlledoscillator[J]. IEEE Trans. Ultrason. Ferroelectr. Freq. Control,2007,54(2):222-226
[61] M. Al-Ahmad, C. Loyez, N. Rolland, et al. Wide BST-based tuning of voltage controlledoscillator[C]. Asia Pacif. Microwave Conf. Proc., APMC, Yokohama, Japan,2006,468-471
[62] L. Y. V. Chen, R. Forse, D. Chase, et al. Analog tunable matching network using integratedthin-film BST capacitors[C]. IEEE MTT S Int. Microwave Symp. Dig., Fort Worth, TX, UnitedStates,2004,261-264
[63] I. Levin, T. G. Amos, J. C. Nino, et al. Structural study of an unusual cubic pyrochloreBi1.5Zn0.92Nb1.5O6.92[J]. J. Solid State Chem.,2002,168(1):69-75
[64] H. Wu, P. K. Davies. Influence of non-stoichiometry on the structure and properties ofBa(Zn1/3Nb2/3)O3microwave dielectrics: II. Compositional variations in pure BZN[J]. J. Am.Ceram. Soc.,2006,89(7):2250-2263
[65] S. Kamba, V. Porokhonskyy, A. Pashkin, et al. Anomalous broad dielectric relaxation inBi1.5Zn1.0Nb1.5O7pyrochlore[J]. Phys. Rev. B,2002,66(5):054106
[66] R. L. Thayer, C. A. Randall, S. Trolier-McKinstry. Medium permittivity bismuth zinc niobatethin film capacitors[J]. J. Appl. Phys.,2003,94(3):1941-1947
[67] A. K. Tagantsev, J. Lu, S. Stemmer. Temperature dependence of the dielectric tunability ofpyrochlore bismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2005,86(3):032901.
[68] Y. P. Hong, S. Ha, H. Y. Lee, et al. Voltage tunable dielectric properties of rf sputteredBi2O3-ZnO-Nb2O5pyrochlore thin films[J]. Thin Solid Films,2002,419(1-2):183-188
[69] J. Lu, S. Stemmer, Low-loss, tunable bismuth zinc niobate films deposited by rf magnetronsputtering[J]. Appl. Phys. Lett.,2003,83(12):2411-2413
[70] S. Ha, Y. S. Lee, Y. P. Hong, et al. The effect of substrate heating on the tunability ofrf-sputtered Bi2O3-ZnO-Nb2O5thin films[J]. Appl. Phys. A,2005,80(3):585-590
[71] J. G. Cheng, J. Wang, T. Dechakupt, et al. Low-temperature crystallized pyrochlore bismuthzinc niobate thin films by excimer laser annealing[J]. Appl. Phys. Lett.,87(23):232905
[72] S. Jiang, B. Jiang, X. Liu, et al. Laser deposition and dielectric properties of cubic pyrochlorebismuth zinc niobate thin films[J]. J. Vac. Sci. Technol. A,2006,24(2):261-263
[73] L. Z. Cao, W. Y. Fu, S. F. Wang, et al. Effects of film thickness and preferred orientation on thedielectric properties of (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7films[J]. J. Phys. D: Appl. Phys.,2007,40(9):2906-2910
[74] K. Sudheendran, K. C. J. Raju, Temperature-dependent dielectric, impedance and tunabilitystudies on bismuth zinc niobate ((Bi1.5Zn0.5)(Zn0.5Nb1.5)O7) ceramics[J]. Ceram. Int.,2008,34(4):897-900
[75] Y. P. Hong, K. H. Ko, H. J. Lee, et al. High-permittivity and low-loss dielectric tunablepyrochlore thin films deposited by radio frequency magnetron sputtering from a lead zincniobate target[J]. Thin Solid Films,2008,516(8):2195-2202
[76] S. Jiang, Y. Li. Effect of zinc content on dielectric properties of cubic pyrochloreBi2O3-ZnO-Nb2O5thin films[J]. Jpn. J. Appl. Phys.,2009,48(12):121402
[77] X. Zhang, W. Ren, P. Shi, et al. Influence of substrate temperature on structures and dielectricproperties of pyrochlore Bi1.5Zn1.0Nb1.5O7thin films prepared by pulsed laser deposition[J].Appl. Surf. Sci.,2010,256(22):6607-6611
[78] X. Zhang, W. Ren, P. Shi, et al. Effect of oxygen pressure on structure and properties ofBi1.5Zn1.0Nb1.5O7pyrochlore thin films prepared by pulsed laser deposition[J]. Appl. Surf. Sci.,2010,256(6):1861-1866
[79] X. Zhang, W. Ren. Influences of post-annealing on structural and electrical properties ofBi1.5Zn1.0Nb1.5O7thin films prepared by pulsed laser deposition[J]. Mater. Sci. Eng. B SolidState Adv. Technol.,2012,177(12):975-980
[80] J. Park, J. Lu, S. Stemmer, et al. Microwave dielectric properties of tunable capacitorsemploying bismuth zinc niobate thin films[J]. J. Appl. Phys.,2005,97(8):084110
[81] J. Lu, S. Schmidt, D. S. Boesch, et al. Low-loss tunable capacitors fabricated directly on goldbottom electrodes[J]. Appl. Phys. Lett.,2006,88(11):112905
[82] J. Park, J. Lu, D. S. Boesch, et al. Distributed phase shifter with pyrochlore bismuth zincniobate thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(5):264-266
[83] L. Yan, L. B. Kong, L. F. Chen, et al. Ba0.5Sr0.5TiO3-Bi1.5Zn1.0Nb1.5O7composite thin filmswith promising microwave dielectric properties for microwave device applications[J]. Appl.Phys. Lett.,2004,85(16):3522-3524
[84] H. Tian, Y. Wang, D. Wang, et al. Dielectric properties and abnormal C-V characteristics ofBa0.5Sr0.5TiO3-Bi1.5ZnNb1.5O7composite thin films grown on MgO (001) substrates by pulsedlaser deposition[J]. Appl. Phys. Lett.,2006,89(14):142905
[85] S. Wang, M. Guo, X. Sun, et al. Tunable, low loss Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3/Bi1.5Zn1.0Nb1.5O7sandwich films[J]. Appl. Phys. Lett.,2006,89(21):212907
[86] J. Singha, S. B. Krupanidhi. Multilayer Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3/Bi1.5Zn1.0Nb1.5O7thinfilms for tunable microwave applications[J]. Appl. Surf. Sci.,2011,257(6):2214-2217
[87] W. Fu, L. Cao, S. Wang, et al. Dielectric properties of Bi1.5Zn1.0Nb1.5O7/Mn-dopedBa0.6Sr0.4TiO3heterolayered films grown by pulsed laser deposition[J]. Appl. Phys. Lett.,2006,89(13):132908
[88] X. Yan, W. Ren, P. Shi, et al. Structures and tunability of Ba0.5Sr0.5TiO3/Bi1.5Zn1.0Nb1.5O7multilayer thin films grown on Pt/Al2O3substrates[J]. Ferroelectrics,2009,384(1):98-105
[89] L. Yang, G. Wang, X. Dong, et al. Improved dielectric properties of Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3bilayered films for tunable microwave applications[J]. J. Am.Ceram. Soc.,2010,93(5):1215-1217
[90] L. Yang, G. Wang, X. Dong, et al. Microwave properties of Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3hetero layered films directly sputtered on Si up to50GHz[J]. J. Am. Ceram. Soc.,2011,94(8):2262-2265
[91]吴自勤,王兵.薄膜生长[M].北京:科学出版社,2003,329-332
[92] J. C. Jiang, Y. Lin, C. L. Chen, et al. Microstructures and surface step-induced antiphaseboundaries in epitaxial ferroelectric Ba0.6Sr0.4TiO3thin film on MgO[J]. J. Appl. Phys.,2002,91(5):3188-3192
[93] T. Delage, C. Champeaux, A. Catherinot, et al. High-K BST films deposited on MgO by PLDwith and without buffer-layer[J]. Thin Solid Films,2004,453:279-284
[94] X. Y. Zhou, D. Y. Wang, R. K. Zheng, et al. Thickness dependence of in-plane dielectric andferroelectric properties of Ba0.7Sr0.3TiO3thin films epitaxially grown on LaAlO3[J]. Appl. Phys.Lett.,2007,90(13):132902
[95] W. Hu, C. Yang, W. Zhang, et al. The diffusion of Pt in BST films on Pt/Ti/SiO2/Si substrate bysol-gel method[J]. J. Sol-Gel Sci. Techn.,2006,39(3):293-298
[96] S. Mseddi, A. Njeh, D. Schneider, et al. X-ray diffraction and surface acoustic wave analysis ofBST/Pt/TiO2/SiO2/Si thin films[J]. J. Appl. Phys.,2011,110(10):104506
[97] G. Velu, J. C. Carru, E. Cattan, et al. Deposition of ferroelectric BST thin films by Sol Gel routein view of electronic applications[J]. Ferroelectrics,2003,288(1):59-69
[98] P. T. Joseph, Y. C. Chen, Y. H. Chu, et al. Microwave properties of BST and BST/BMT thinfilms grown on sapphire substrate by evanescent microwave probe[J]. Integr. Ferroelectr.,2005,77(1):45-50
[99] L. Xiao, K. L. Choy, I. Harrison. Co-doped BST thin films for tunable microwaveapplications[J]. Surf. Coat. Technol.,2011,205(8-9):2989-2993
[100] J. Deng, O. K. Tan, W. Zhu, et al. Investigation of influence of hydrogen gas on Pd/BST/Ptdevice by impedance spectroscopy[J]. IEEE Trans. Ultrason. Ferroelectr. Freq. Control,2004,51(8):923-928
[101] R. B. Zhang, C. S. Yang, G. P. Ding. The effects of oxygen partial pressure on BST thin filmsdeposited on multilayered bottom electrodes[J]. Mater. Lett.,2005,59(14-15):1741-1744
[102] J. P. Maria, B. Boyette, A. Kingon, et al. Low loss tungsten-based electrode technology formicrowave frequency BST varactors[J]. J Electroceram.,2005,14(1):75-81
[103] T. Aoyama, S. Yamazaki, K. Imai, et al. Characteristics of (Ba, Sr)TiO3capacitors withtextured Ru bottom electrode[J]. Jpn. J. Appl. Phys. Part1Regul. Pap. Short Note Rev. Pap.,2000,39(11):6348-6357
[104] M. Tarutani, M. Yamamuka, T. Takenaga, et al. Improved fabrication process for Ru/BST/Rucapacitor by liquid source chemical vapor deposition[J]. Thin Solid Films,2002,409(1):8-14
[105] J. Wang, T. Zhang, B. Zhang, et al. Interfacial characteristic of (Ba,Sr)TiO3thin filmsdeposited on different bottom electrodes[J]. J. Mater. Sci. Mater. Electron.,2009,20(12):1208-1213
[106] I. D. Kim, H. L. Tuller, H. S. Kim, et al. High tunability (Ba, Sr)TiO3thin films grown onatomic layer deposited TiO2and Ta2O5buffer layers[J]. Appl. Phys. Lett.,2004,85(20):4705-4707
[107] I. B. Vendik, O. G. Vendik, E. L. Kollberg. Commutation quality factor of two-state switchabledevices[J]. IEEE Trans. Microw. Theory Tech.,2000,48(5):802-808
[108] K. Sudheendran, M. G. Krishna, K. C. J. Raju. Effect of process parameters andpost-deposition annealing on the microwave dielectric and optical properties of pulsed laserdeposited Bi1.5Zn1.0Nb1.5O7thin films[J]. Appl. Phys. A,2009,95(2):485-492
[109] K. Sudheendran, K. C. J. Raju. Influence of post deposition annealing process on the opticaland microwave dielectric properties of Bi1.5Zn1.0Nb1.5O7thin films[J]. Integr. Ferroelectr.,2010,119(1):89-95
[110] S. T. Chang, J. Y. M. Lee. Electrical conduction mechanism in high-dielectric-constant (Ba0.5,Sr0.5)TiO3thin films[J]. Appl. Phys. Lett.,2002,80(4):655-657
[111] H. Seo, Y. B. Kim, G. Lucovsky, et al. Enhanced leakage current properties of Ni-dopedBa0.6Sr0.4TiO3thin films driven by modified band edge state[J]. J. Appl. Phys.,2010,107(2):024109
[112]施敏,伍国钰.半导体器件物理[M].(耿莉,张瑞智).西安:西安交通大学出版社,2008,173-174
[113] R. Schafranek, S. Payan, M. Maglione, et al. Barrier height at (Ba,Sr)TiO3/Pt interfacesstudied by photoemission[J]. Phys. Rev. B,2008,77(19):195310
[114] D. Kim. Monolithic anolog phase shifters based on barium strontium titanate coated sapphiresubstrates for WLAN applications[D]. Georgia, USA: Georgia Institute of Technology,2004,40-50
[115] A. Tombak, J. P. Maria, F. Ayguavives, et al. Tunable barium strontium titanate thin filmcapacitors for RF and microwave applications[J]. IEEE Microw. Wirel. Compon. Lett.,2002,12(1):3-5
[116] S. S. Gevorgian, T. Martinsson, P. L. J. Linner, et al. CAD models for multilayered substrateinterdigital capacitors[J]. IEEE Trans. Microw. Theory Tech.,1996,44(6):896-904
[117] X. Zhu. Switchable and tunable ferroelectric thin film radio frequency components[D].Michigan, USA: University of Michigan,2009,24-34
[118] J. C. Booth, N. D. Orloff, J. Cagnon, et al. Temperature-dependent dielectric relaxation inbismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2010,97(2):022902
[119] J. C. Nino, M. T. Lanagan, C. A. Randall, et al. Correlation between infrared phonon modesand dielectric relaxation in Bi2O3-ZnO-Nb2O5cubic pyrochlore[J]. Appl. Phys. Lett.,2002,81(23):4404-4406
[120] J. Lu, D. O. Klenov, S. Stemmer. Influence of strain on the dielectric relaxation of pyrochlorebismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2004,84(6):957-959
[121] Q. Wang, H. Wang, X. Yao. Structure, dielectric and optical properties of Bi1.5+xZnNb1.5O7+1.5xpyrochlores[J]. Ceram. Int.,2009,35:143-146
[122] D. Kim, Y. Choi, M. Ahn, et al.2.4GHz continuously variable ferroelectric phase shifter usingall-pass networks[J]. IEEE Microw. Wirel. Compon. Lett.,2003,13(10):434-436
[123] D. Kim, Y. Choi, Mark G. Allen, et al. A wide-band reflection-type phase shifter at S-bandusing BST coated substrate[J]. IEEE Trans. Microw. Theory Tech.,2002,50(12):2903-2909
[124] J. L. Serraiocco, P. J. Hansen, T. R. Taylor, et al. Compact ferroelectric reflection phaseshifters at X-band[C]. IEEE MTT S Int. Microwave Symp. Dig., Philadelphia, PA, UnitedStates,2003,1993-1996
[125] V. Sherman, K. Astafiev, N. Setter, et al. Digital reflection-type phase shifter based on aferroelectric planar capacitor[J]. IEEE Microw. Wirel. Compon. Lett.,2001,11(10):407-409
[126] D. Kim, Y. Choi, M. Ahn, et al. Monolithic180°and360°analog phase shifters based onbarium-strontium-titanate coated substrate[J]. IEICE Trans. Electron.,2003, E86-C(8):1607-1612
[127] H. C. Ryu, S. E. Moon, S. J. Lee, et al. Design of a Ka-band coupled microstrip lineferroelectric phase shifters[J]. Integr. Ferroelectr.,2005,77(1):129-137
[128] F. D. Flaviis, N. G. Alexopoulos, O. M. Stafsudd. Planar microwave integrated phase-shifterdesign with high purity ferroelectric material[J]. IEEE Trans. Microw. Theory Tech.,1997,45(6):963-969
[129] A. Kozyrev, V. Osadchy, A. Pavlov, et al. Application of ferroelectrics in phase shifterdesign[C]. IEEE MTT S Int. Microwave Symp. Dig., Boston, MA, USA,2000,1355-1358
[130] G. Velu, K. Blary, L. Burgnies, et al. A310°/3.6-dB K-band phase shifter using paraelectricBST thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(2):87-89
[131] A. S. Nagra, R. A. York. Distributed analog phase shifters with low insertion loss[J]. IEEETrans. Microw. Theory Tech.,1999,47(9):1705-1711
[132] M. J. W. Rodwell, M. Kamegawa, R. Yu, et al. GaAs nonlinear transmission lines forpicosecond pulse generation and millimeter-wave sampling[J]. IEEE Trans. Microw. TheoryTech.,1991,39(7):1194-1204
[2] K. M. Johnson. Microwave varactor tuned transistor oscillator design[J]. IEEE Trans. Microw.Theory Tech.,1966,14(11):564-572
[3] L. Lin, C. Nguyen, R. T. Howe, et al. Micro electromechanical filters for signal processing[C].Proc. IEEE Micro. Electro. Mech. Syst. Workshop, Travemuende, Ger,1992,226-231
[4] F. Reggia, E. G. Spencer. A new technique in ferrite phase shifting for beam scanning ofmicrowave antennas[J]. Proc. IRE,1957,45(11):1510-1517
[5] P. Bao, T. J. Jackson, X. Wang, et al. Barium strontium titanate thin film varactors forroom-temperature microwave device applications[J]. J. Phys. D: Appl. Phys.,2008,41(6):063001
[6] A. K. Tagantsev, V. O. Sherman, K. F. Astafiev, et al. Ferroelectric materials for microwavetunable applications[J]. J. Electroceramics,2003,11(1-2):5-66
[7] N. Setter, D. Damjanovic, L. Eng, et al. Ferroelectric thin films: Review of materials, properties,and applications[J]. J. Appl. Phys.,2006,100(5):051606
[8] S. S. Gevorgian, E. L. Kollberg. Do we really need ferroelectrics in paraelectric phase only inelectrically controlled microwave devices?[J]. IEEE Trans. Microw. Theory Tech.,2001,49(11):2117-2124
[9] M. D. Domenico, D. A. Johnson, R. H. Pantell. Ferroelectric harmonic generator and thelarge-signal microwave characteristics of a ferroelectric ceramic[J]. J. Appl. Phys.,1962,33(5):1697-1706
[10] W. Ren, S. Trolier-McKinstry, C. A. Randall, et al. Bismuth zinc niobate pyrochlore dielectricthin films for capacitive applications[J]. J. Appl. Phys.,2001,89(1):767-774
[11] W. Fu, H. Wang, L. Cao, et al. Bi1.5Zn1.0Nb1.5O7/Mn-doped Ba0.6Sr0.4TiO3heterolayered thinfilms with enhanced tunable performance[J]. Appl. Phys. Lett.,2008,92(18):182910
[12] S. Wang. Preparation and characterization of ferroelectric thin films for tunable and pyroelectricapplications[D]. Singapore: National University of Singapore,2011,12
[13]黄静.钙钛矿结构微波陶瓷介电机理的研究[D].武汉:华中科技大学,2004,68-78
[14] J. Im, O. Auciello, P. K. Baumann, et al. Composition-control of magnetron-sputter-deposited(BaxSr1–x)Ti1+yO3+zthin films for voltage tunable devices[J]. Appl. Phys. Lett.,2000,76(5):625-627
[15] N. K. Pervez, P. J. Hansen, R. A. York. Optimization of high tunability barium strontiumtitanate thin films grown by rf magnetron sputtering[C]. IEEE Int. Symp. Appl. Ferroelectr.,Montreal, Canada,2005,278-280
[16] P. Padmini, T. R. Taylor, M. J. Lefevre, et al. Realization of high tunability barium strontiumtitanate thin films grown by rf magnetron sputtering[J]. Appl. Phys. Lett.,1999,75(20):3186-3188
[17] H. S. Kim, T. S. Hyum, H. G. Kim, et al. Orientation effect on microwave dielectric propertiesof Si-integrated Ba0.6Sr0.4TiO3thin films for frequency agile devices[J]. Appl. Phys. Lett.,2006,89(5):052902
[18] S. E. Moon, E. K. Kim, M. H. Kwak, et al. Orientation dependent microwave dielectricproperties of ferroelectric Ba1–xSrxTiO3thin films[J]. Appl. Phys. Lett.,2003,83(11):2166-2168
[19] W. Chang, J. M. Pond, S. W. Kirchoefer, et al. Strain-induced anisotropy in microwavedielectric properties of (Ba, Sr) TiO3thin films with directly applied uniaxial <100> stress[J].Appl. Phys. Lett.,2005,87(24):242904
[20] S. Anuranjan, D. Kumar, K. Rajiv. LaNiO3as contact material for (Ba, Sr) TiO3dielectric thinfilms[J]. Electrochem. Solid-State Lett.,1999,2(6):294-296
[21] G. Akcay, I. B. Misirlioglu, S. P. Alpay. Dielectric and pyroelectric properties of bariumstrontium titanate films on orthorhombic substrates with (110)//(100) epitaxy[J]. J. Appl. Phys.,2007,101(10):104110
[22] Y. Tomoaki, O. S. Vladimir, N. Andreas. Epitaxial/amorphous Ba0.3Sr0.7TiO3film compositestructure for tunable applications[J]. Appl. Phys. Lett.,2006,89(3):032905
[23] H. W. Wang, S. W. Ni, K. C. Lee. Enhanced tunability and electrical properties of bariumstrontium titanate thin films by gold doping in grains[J]. Appl. Phys. Lett.,2004,84(15):2874-2876
[24] B. H. Park, E. J. Peterson, Q. X. Jia. Effects of very thin strain layers on dielectric propertiesof epitaxial Ba0.6Sr0.4TiO3films[J]. Appl. Phys. Lett.,2001,78(4):533-535
[25] S. Hyun, J. H. Lee, S. S. Kim, et al. Anisotropic tuning behavior in epitaxial Ba0.5Sr0.5TiO3thinfilms[J]. Appl. Phys. Lett.,2000,77(19):3084-3086
[26] M. Jain, S. B. Majumder, R. S. Katiyar, et al. Improvement in electrical characteristics ofgraded manganese doped barium strontium titanate thin films[J]. Appl. Phys. Lett.,2003,82(12):1911-1913
[27] E. Ngo, P. C. Joshi, M. W. Cole, et al. Electrophoretic deposition of pure and MgO-modifiedBa0.6Sr0.4TiO3thick films for tunable microwave devices[J]. Appl. Phys. Lett.,2001,79(2):248-250
[28] S. Y. Lee, T. Y. Tseng. Electrical and dielectric behavior of MgO doped Ba0.7Sr0.3TiO3thin filmson Al2O3substrate[J]. Appl. Phys. Lett.,2002,80(10):1797-1799
[29] P. C. Joshia, M. W. Cole. Mg doped Ba0.6Sr0.4TiO3thin films for tunable microwaveapplications[J]. Appl. Phys. Lett.,2000,77(2):289-291
[30] M. W. Cole, W. D. Nothwang, C. Hubbard, et al. Low dielectric loss and enhanced tunability ofBa0.6Sr0.4TiO3based thin films via material compositional design and optimized film processingmethods[J]. J. Appl. Phys.,2003,93(11):9218-9225
[31] X. Liang, W. Wu, Z. Meng, et al. Dielectric and tunable characteristics of barium strontiumtitanate modified with Al2O3addition[J]. Mater. Sci. Eng. B,2003,99(1-3):366-369
[32] K. B. Chong, L. B. Kong, L. Chen, et al. Improvement of dielectric loss tangent of Al2O3dopedBa0.5Sr0.5TiO3thin films for tunable microwave devices[J]. J. Appl. Phys.,2004,95(3):1416-1419
[33] M. Lorenz, H. Hochmuth, M. Schallner, et al. Dielectric properties of Fe doped BaxSr1-xTiO3thin films on polycrystalline subst rates at temperatures between-35and+85℃[J].Solid-StateElectron.,2003,47(12):2199-2203
[34] J. Gong, J. Cheng, W. Zhu, et al. Improvement in dielectric and tunable properties of Fe-dopedBa0.6Sr0.4TiO3thin films grown by pulsed-laser deposition[J]. IEEE Trans. Ultrason. Ferroelectr.Freq. Control,2007,54(12):2579-2582
[35] K. T. Kang, M. H. Lim, H. G. Kim, et al. Mn-doped Ba0.6Sr0.4TiO3high-K gate dielectrics forlow voltage organic transistor on polymer substrate[J]. Appl. Phys. Lett.,2005,87(24):242908
[36] X. H. Zhu, D. N. Zheng, W. Peng, et al. Enhanced dielectric properties of Mn dopeBa0.6Sr0.4TiO3thin films fabricated by pulsed laser deposition[J]. Mater. Lett.,2006,60(9-10):1224-1228
[37] K. H. Ahn, S. Baik. Significant suppression of leakage current in (Ba, Sr) TiO3thin films by Nior Mn doping[J]. J. Appl. Phys.,2002,92(5):2651-2654
[38] H. Seo, Y. B. Kim, G. Lucovsky, et al. Enhanced leakage current properties of Ni-dopedBa0.6Sr0.4TiO3thin films driven by modified band edge state[J]. J. Appl. Phys.,2010,107(2):024109
[39] J. K. Kim, S. S. Kim, W. J. Kim, et al. Improved ferroelectric properties of Cr-dopedBa0.7Sr0.3TiO3thin films prepared by wet chemical deposition[J]. Mater. Lett.,2006,60(19):2322-2325
[40] H. S. Kim, H. G. Kim, I. D. Kim, et al. High-tunability and low-microwave-loss Ba0.6Sr0.4TiO3thin films grown on high-resistivity Si substrates using TiO2buffer layers[J]. Appl. Phys. Lett.,2005,87(21):212903
[41] Y. H. Gao, J. H. Ma, T. X. Li, et al. Improved dielectric and electrical behaviour oflow-temperature deposited (Ba0.6Sr0.4)TiO3films by thin SrTiO3buffer layer[J]. J. Phys. D:Appl. Phys.,2008,41(8):085305
[42] W. Zhu, J. Cheng, S. Yu, et al. Enhanced tunable properties of Ba0.6Sr0.4TiO3thin films grownon Pt/Ti/SiO2/Si substrates using MgO buffer layers[J]. Appl. Phys. Lett.,2007,90(3):032907
[43] N. Xiong, S. Jiang, Y. Li, et al. Dielectric properties of Ba0.5Sr0.5TiO3/SiN bilayered thin filmsgrown on Pt-coated sapphire substrates[J]. Appl. Phys. Lett.,2008,93(23):232905
[44] Y. Liu, A.S. Nagra, E.G. Erker, et al. BaSrTiO3interdigitated capacitors for distributed phaseshifter applications[J]. IEEE Microw. Guided Wave Lett.,2000,10(11):448-450
[45] B. Acikel, Y. Liu, A. S. Nagra, et al. Phase shifters using (Ba, Sr)TiO3thin films on sapphireand glass substrate[C]. IEEE MTT S Int. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1191-1194
[46] I. P. Koutsaroff, T. Bernacki, M. Zelner, et al. Microwave properties of parallel plate capacitorsbased on (Ba, Sr)TiO3thin films grown on SiO2/Al2O3substrates[C]. Mat. Res. Soc. Symp.Proc. Boston, MA, United States,2003,784,319-325
[47] A. Vorobiev, P. Rundqvist, K. Khamchane, et al. Silicon substrate integrated high Q-factorparallel-plate ferroelectric varactors for microwave/millimeterwave applications[J]. Appl. Phys.Lett.,2003,83(15):3144-3146
[48] E. G. Erker, A. S. Nagra, Y. Liu, et al. Monolithic Ka-band phase shifter using voltage tunableBaSrTiO3parallel plate capacitors[J]. IEEE Microw. Guided Wave Lett.,2000,10(1):10-12
[49] B. Acikel, T. R. Taylor, P. J. Hansen, et al. A new high performance phase shifter usingBaxSr1-xTiO3thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2002,12(7):237-239
[50] A. Mahmud, T. S. Kalkur, A. Jamil, et al. A1-GHz active phase shifter with a ferroelectricvaractor[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(5):261-263
[51] Z. Y. Zhao, X. Y. Wang, K. Choi, et al. Ferroelectric phase shifters at20and30GHz[J]. IEEETrans. Microw. Theory Tech.,2007,55(2):430-437
[52] G. Vélu, K. Blary, L. Burgnies, et al. A360°BST phase shifter with moderate bias voltage at30GHz[J]. IEEE Trans. Microw. Theory Tech.,2007,55(2):438-444
[53] K. B. Kim, T. S. Yun, J. C. Lee, et al. Integration of coplanar (Ba, Sr)TiO3microwave phaseshifters onto Si wafers using TiO2buffer layers[J]. IEEE Trans. Ultrason. Ferroelectr. Freq.Control,2006,53(3):518-524
[54] S. Sheng, P. Wang, X. Chen, et al. Two paralleled Ba0.25Sr0.75TiO3ferroelectric varactors seriesconnected coplanar waveguide microwave phase shifter[J]. J. Appl. Phys.,2009,105(11):114509
[55] Q. D. Meng, X. Q. Zhang, F. Li, et al. An impedance matched phase shifter using BaSrTiO3thinfilm[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(6):345-347
[56] H. Chen, C. Yang, J. Zhang, et al. High performance distributed CPW phase shifters withetched BST thin films on Ф3’’ LaAlO3substrates[J]. Solid State Sci.,2012,14(1):117-120
[57] J. Nath, D. Ghosh, J.-P. Maria, et al. An electronically tunable microstrip bandpass filter usingthin-film barium-strontium-titanate (BST) varactors[J]. IEEE Trans. Microw. Theory Tech.,2005,53(9):2707-2712
[58] X. P. Liang, Y. Zhu. Hybrid resonator microstrip line electrically tunable filter[C]. IEEE MTT SInt. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1457-1460
[59] J. Xu, X. P. Liang, S. Khosro. Full wave analysis and design of RF tunable filters[C]. IEEEMTT S Int. Microwave Symp. Dig., Phoenix, AZ, United States,2001,1449-1452
[60] A. Jamil, T. S. Kalkur, N. Cramer. Tunable ferroelectric capacitor-based voltage-controlledoscillator[J]. IEEE Trans. Ultrason. Ferroelectr. Freq. Control,2007,54(2):222-226
[61] M. Al-Ahmad, C. Loyez, N. Rolland, et al. Wide BST-based tuning of voltage controlledoscillator[C]. Asia Pacif. Microwave Conf. Proc., APMC, Yokohama, Japan,2006,468-471
[62] L. Y. V. Chen, R. Forse, D. Chase, et al. Analog tunable matching network using integratedthin-film BST capacitors[C]. IEEE MTT S Int. Microwave Symp. Dig., Fort Worth, TX, UnitedStates,2004,261-264
[63] I. Levin, T. G. Amos, J. C. Nino, et al. Structural study of an unusual cubic pyrochloreBi1.5Zn0.92Nb1.5O6.92[J]. J. Solid State Chem.,2002,168(1):69-75
[64] H. Wu, P. K. Davies. Influence of non-stoichiometry on the structure and properties ofBa(Zn1/3Nb2/3)O3microwave dielectrics: II. Compositional variations in pure BZN[J]. J. Am.Ceram. Soc.,2006,89(7):2250-2263
[65] S. Kamba, V. Porokhonskyy, A. Pashkin, et al. Anomalous broad dielectric relaxation inBi1.5Zn1.0Nb1.5O7pyrochlore[J]. Phys. Rev. B,2002,66(5):054106
[66] R. L. Thayer, C. A. Randall, S. Trolier-McKinstry. Medium permittivity bismuth zinc niobatethin film capacitors[J]. J. Appl. Phys.,2003,94(3):1941-1947
[67] A. K. Tagantsev, J. Lu, S. Stemmer. Temperature dependence of the dielectric tunability ofpyrochlore bismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2005,86(3):032901.
[68] Y. P. Hong, S. Ha, H. Y. Lee, et al. Voltage tunable dielectric properties of rf sputteredBi2O3-ZnO-Nb2O5pyrochlore thin films[J]. Thin Solid Films,2002,419(1-2):183-188
[69] J. Lu, S. Stemmer, Low-loss, tunable bismuth zinc niobate films deposited by rf magnetronsputtering[J]. Appl. Phys. Lett.,2003,83(12):2411-2413
[70] S. Ha, Y. S. Lee, Y. P. Hong, et al. The effect of substrate heating on the tunability ofrf-sputtered Bi2O3-ZnO-Nb2O5thin films[J]. Appl. Phys. A,2005,80(3):585-590
[71] J. G. Cheng, J. Wang, T. Dechakupt, et al. Low-temperature crystallized pyrochlore bismuthzinc niobate thin films by excimer laser annealing[J]. Appl. Phys. Lett.,87(23):232905
[72] S. Jiang, B. Jiang, X. Liu, et al. Laser deposition and dielectric properties of cubic pyrochlorebismuth zinc niobate thin films[J]. J. Vac. Sci. Technol. A,2006,24(2):261-263
[73] L. Z. Cao, W. Y. Fu, S. F. Wang, et al. Effects of film thickness and preferred orientation on thedielectric properties of (Bi1.5Zn0.5)(Zn0.5Nb1.5)O7films[J]. J. Phys. D: Appl. Phys.,2007,40(9):2906-2910
[74] K. Sudheendran, K. C. J. Raju, Temperature-dependent dielectric, impedance and tunabilitystudies on bismuth zinc niobate ((Bi1.5Zn0.5)(Zn0.5Nb1.5)O7) ceramics[J]. Ceram. Int.,2008,34(4):897-900
[75] Y. P. Hong, K. H. Ko, H. J. Lee, et al. High-permittivity and low-loss dielectric tunablepyrochlore thin films deposited by radio frequency magnetron sputtering from a lead zincniobate target[J]. Thin Solid Films,2008,516(8):2195-2202
[76] S. Jiang, Y. Li. Effect of zinc content on dielectric properties of cubic pyrochloreBi2O3-ZnO-Nb2O5thin films[J]. Jpn. J. Appl. Phys.,2009,48(12):121402
[77] X. Zhang, W. Ren, P. Shi, et al. Influence of substrate temperature on structures and dielectricproperties of pyrochlore Bi1.5Zn1.0Nb1.5O7thin films prepared by pulsed laser deposition[J].Appl. Surf. Sci.,2010,256(22):6607-6611
[78] X. Zhang, W. Ren, P. Shi, et al. Effect of oxygen pressure on structure and properties ofBi1.5Zn1.0Nb1.5O7pyrochlore thin films prepared by pulsed laser deposition[J]. Appl. Surf. Sci.,2010,256(6):1861-1866
[79] X. Zhang, W. Ren. Influences of post-annealing on structural and electrical properties ofBi1.5Zn1.0Nb1.5O7thin films prepared by pulsed laser deposition[J]. Mater. Sci. Eng. B SolidState Adv. Technol.,2012,177(12):975-980
[80] J. Park, J. Lu, S. Stemmer, et al. Microwave dielectric properties of tunable capacitorsemploying bismuth zinc niobate thin films[J]. J. Appl. Phys.,2005,97(8):084110
[81] J. Lu, S. Schmidt, D. S. Boesch, et al. Low-loss tunable capacitors fabricated directly on goldbottom electrodes[J]. Appl. Phys. Lett.,2006,88(11):112905
[82] J. Park, J. Lu, D. S. Boesch, et al. Distributed phase shifter with pyrochlore bismuth zincniobate thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(5):264-266
[83] L. Yan, L. B. Kong, L. F. Chen, et al. Ba0.5Sr0.5TiO3-Bi1.5Zn1.0Nb1.5O7composite thin filmswith promising microwave dielectric properties for microwave device applications[J]. Appl.Phys. Lett.,2004,85(16):3522-3524
[84] H. Tian, Y. Wang, D. Wang, et al. Dielectric properties and abnormal C-V characteristics ofBa0.5Sr0.5TiO3-Bi1.5ZnNb1.5O7composite thin films grown on MgO (001) substrates by pulsedlaser deposition[J]. Appl. Phys. Lett.,2006,89(14):142905
[85] S. Wang, M. Guo, X. Sun, et al. Tunable, low loss Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3/Bi1.5Zn1.0Nb1.5O7sandwich films[J]. Appl. Phys. Lett.,2006,89(21):212907
[86] J. Singha, S. B. Krupanidhi. Multilayer Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3/Bi1.5Zn1.0Nb1.5O7thinfilms for tunable microwave applications[J]. Appl. Surf. Sci.,2011,257(6):2214-2217
[87] W. Fu, L. Cao, S. Wang, et al. Dielectric properties of Bi1.5Zn1.0Nb1.5O7/Mn-dopedBa0.6Sr0.4TiO3heterolayered films grown by pulsed laser deposition[J]. Appl. Phys. Lett.,2006,89(13):132908
[88] X. Yan, W. Ren, P. Shi, et al. Structures and tunability of Ba0.5Sr0.5TiO3/Bi1.5Zn1.0Nb1.5O7multilayer thin films grown on Pt/Al2O3substrates[J]. Ferroelectrics,2009,384(1):98-105
[89] L. Yang, G. Wang, X. Dong, et al. Improved dielectric properties of Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3bilayered films for tunable microwave applications[J]. J. Am.Ceram. Soc.,2010,93(5):1215-1217
[90] L. Yang, G. Wang, X. Dong, et al. Microwave properties of Bi1.5Zn1.0Nb1.5O7/Ba0.6Sr0.4TiO3hetero layered films directly sputtered on Si up to50GHz[J]. J. Am. Ceram. Soc.,2011,94(8):2262-2265
[91]吴自勤,王兵.薄膜生长[M].北京:科学出版社,2003,329-332
[92] J. C. Jiang, Y. Lin, C. L. Chen, et al. Microstructures and surface step-induced antiphaseboundaries in epitaxial ferroelectric Ba0.6Sr0.4TiO3thin film on MgO[J]. J. Appl. Phys.,2002,91(5):3188-3192
[93] T. Delage, C. Champeaux, A. Catherinot, et al. High-K BST films deposited on MgO by PLDwith and without buffer-layer[J]. Thin Solid Films,2004,453:279-284
[94] X. Y. Zhou, D. Y. Wang, R. K. Zheng, et al. Thickness dependence of in-plane dielectric andferroelectric properties of Ba0.7Sr0.3TiO3thin films epitaxially grown on LaAlO3[J]. Appl. Phys.Lett.,2007,90(13):132902
[95] W. Hu, C. Yang, W. Zhang, et al. The diffusion of Pt in BST films on Pt/Ti/SiO2/Si substrate bysol-gel method[J]. J. Sol-Gel Sci. Techn.,2006,39(3):293-298
[96] S. Mseddi, A. Njeh, D. Schneider, et al. X-ray diffraction and surface acoustic wave analysis ofBST/Pt/TiO2/SiO2/Si thin films[J]. J. Appl. Phys.,2011,110(10):104506
[97] G. Velu, J. C. Carru, E. Cattan, et al. Deposition of ferroelectric BST thin films by Sol Gel routein view of electronic applications[J]. Ferroelectrics,2003,288(1):59-69
[98] P. T. Joseph, Y. C. Chen, Y. H. Chu, et al. Microwave properties of BST and BST/BMT thinfilms grown on sapphire substrate by evanescent microwave probe[J]. Integr. Ferroelectr.,2005,77(1):45-50
[99] L. Xiao, K. L. Choy, I. Harrison. Co-doped BST thin films for tunable microwaveapplications[J]. Surf. Coat. Technol.,2011,205(8-9):2989-2993
[100] J. Deng, O. K. Tan, W. Zhu, et al. Investigation of influence of hydrogen gas on Pd/BST/Ptdevice by impedance spectroscopy[J]. IEEE Trans. Ultrason. Ferroelectr. Freq. Control,2004,51(8):923-928
[101] R. B. Zhang, C. S. Yang, G. P. Ding. The effects of oxygen partial pressure on BST thin filmsdeposited on multilayered bottom electrodes[J]. Mater. Lett.,2005,59(14-15):1741-1744
[102] J. P. Maria, B. Boyette, A. Kingon, et al. Low loss tungsten-based electrode technology formicrowave frequency BST varactors[J]. J Electroceram.,2005,14(1):75-81
[103] T. Aoyama, S. Yamazaki, K. Imai, et al. Characteristics of (Ba, Sr)TiO3capacitors withtextured Ru bottom electrode[J]. Jpn. J. Appl. Phys. Part1Regul. Pap. Short Note Rev. Pap.,2000,39(11):6348-6357
[104] M. Tarutani, M. Yamamuka, T. Takenaga, et al. Improved fabrication process for Ru/BST/Rucapacitor by liquid source chemical vapor deposition[J]. Thin Solid Films,2002,409(1):8-14
[105] J. Wang, T. Zhang, B. Zhang, et al. Interfacial characteristic of (Ba,Sr)TiO3thin filmsdeposited on different bottom electrodes[J]. J. Mater. Sci. Mater. Electron.,2009,20(12):1208-1213
[106] I. D. Kim, H. L. Tuller, H. S. Kim, et al. High tunability (Ba, Sr)TiO3thin films grown onatomic layer deposited TiO2and Ta2O5buffer layers[J]. Appl. Phys. Lett.,2004,85(20):4705-4707
[107] I. B. Vendik, O. G. Vendik, E. L. Kollberg. Commutation quality factor of two-state switchabledevices[J]. IEEE Trans. Microw. Theory Tech.,2000,48(5):802-808
[108] K. Sudheendran, M. G. Krishna, K. C. J. Raju. Effect of process parameters andpost-deposition annealing on the microwave dielectric and optical properties of pulsed laserdeposited Bi1.5Zn1.0Nb1.5O7thin films[J]. Appl. Phys. A,2009,95(2):485-492
[109] K. Sudheendran, K. C. J. Raju. Influence of post deposition annealing process on the opticaland microwave dielectric properties of Bi1.5Zn1.0Nb1.5O7thin films[J]. Integr. Ferroelectr.,2010,119(1):89-95
[110] S. T. Chang, J. Y. M. Lee. Electrical conduction mechanism in high-dielectric-constant (Ba0.5,Sr0.5)TiO3thin films[J]. Appl. Phys. Lett.,2002,80(4):655-657
[111] H. Seo, Y. B. Kim, G. Lucovsky, et al. Enhanced leakage current properties of Ni-dopedBa0.6Sr0.4TiO3thin films driven by modified band edge state[J]. J. Appl. Phys.,2010,107(2):024109
[112]施敏,伍国钰.半导体器件物理[M].(耿莉,张瑞智).西安:西安交通大学出版社,2008,173-174
[113] R. Schafranek, S. Payan, M. Maglione, et al. Barrier height at (Ba,Sr)TiO3/Pt interfacesstudied by photoemission[J]. Phys. Rev. B,2008,77(19):195310
[114] D. Kim. Monolithic anolog phase shifters based on barium strontium titanate coated sapphiresubstrates for WLAN applications[D]. Georgia, USA: Georgia Institute of Technology,2004,40-50
[115] A. Tombak, J. P. Maria, F. Ayguavives, et al. Tunable barium strontium titanate thin filmcapacitors for RF and microwave applications[J]. IEEE Microw. Wirel. Compon. Lett.,2002,12(1):3-5
[116] S. S. Gevorgian, T. Martinsson, P. L. J. Linner, et al. CAD models for multilayered substrateinterdigital capacitors[J]. IEEE Trans. Microw. Theory Tech.,1996,44(6):896-904
[117] X. Zhu. Switchable and tunable ferroelectric thin film radio frequency components[D].Michigan, USA: University of Michigan,2009,24-34
[118] J. C. Booth, N. D. Orloff, J. Cagnon, et al. Temperature-dependent dielectric relaxation inbismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2010,97(2):022902
[119] J. C. Nino, M. T. Lanagan, C. A. Randall, et al. Correlation between infrared phonon modesand dielectric relaxation in Bi2O3-ZnO-Nb2O5cubic pyrochlore[J]. Appl. Phys. Lett.,2002,81(23):4404-4406
[120] J. Lu, D. O. Klenov, S. Stemmer. Influence of strain on the dielectric relaxation of pyrochlorebismuth zinc niobate thin films[J]. Appl. Phys. Lett.,2004,84(6):957-959
[121] Q. Wang, H. Wang, X. Yao. Structure, dielectric and optical properties of Bi1.5+xZnNb1.5O7+1.5xpyrochlores[J]. Ceram. Int.,2009,35:143-146
[122] D. Kim, Y. Choi, M. Ahn, et al.2.4GHz continuously variable ferroelectric phase shifter usingall-pass networks[J]. IEEE Microw. Wirel. Compon. Lett.,2003,13(10):434-436
[123] D. Kim, Y. Choi, Mark G. Allen, et al. A wide-band reflection-type phase shifter at S-bandusing BST coated substrate[J]. IEEE Trans. Microw. Theory Tech.,2002,50(12):2903-2909
[124] J. L. Serraiocco, P. J. Hansen, T. R. Taylor, et al. Compact ferroelectric reflection phaseshifters at X-band[C]. IEEE MTT S Int. Microwave Symp. Dig., Philadelphia, PA, UnitedStates,2003,1993-1996
[125] V. Sherman, K. Astafiev, N. Setter, et al. Digital reflection-type phase shifter based on aferroelectric planar capacitor[J]. IEEE Microw. Wirel. Compon. Lett.,2001,11(10):407-409
[126] D. Kim, Y. Choi, M. Ahn, et al. Monolithic180°and360°analog phase shifters based onbarium-strontium-titanate coated substrate[J]. IEICE Trans. Electron.,2003, E86-C(8):1607-1612
[127] H. C. Ryu, S. E. Moon, S. J. Lee, et al. Design of a Ka-band coupled microstrip lineferroelectric phase shifters[J]. Integr. Ferroelectr.,2005,77(1):129-137
[128] F. D. Flaviis, N. G. Alexopoulos, O. M. Stafsudd. Planar microwave integrated phase-shifterdesign with high purity ferroelectric material[J]. IEEE Trans. Microw. Theory Tech.,1997,45(6):963-969
[129] A. Kozyrev, V. Osadchy, A. Pavlov, et al. Application of ferroelectrics in phase shifterdesign[C]. IEEE MTT S Int. Microwave Symp. Dig., Boston, MA, USA,2000,1355-1358
[130] G. Velu, K. Blary, L. Burgnies, et al. A310°/3.6-dB K-band phase shifter using paraelectricBST thin films[J]. IEEE Microw. Wirel. Compon. Lett.,2006,16(2):87-89
[131] A. S. Nagra, R. A. York. Distributed analog phase shifters with low insertion loss[J]. IEEETrans. Microw. Theory Tech.,1999,47(9):1705-1711
[132] M. J. W. Rodwell, M. Kamegawa, R. Yu, et al. GaAs nonlinear transmission lines forpicosecond pulse generation and millimeter-wave sampling[J]. IEEE Trans. Microw. TheoryTech.,1991,39(7):1194-1204