摘要
基于液晶材料(LC)的双折射特性提出了一种基于液晶材料的短十字型阵列电控超材料,超材料包括了上层石英板,金属结构阵,中间液晶介质层,金属地板以及下层石英板。相比于传统的阵列天线设计,运用了新的相位补偿方法,即通过加电改变反射阵列单元的介质基板液晶的介电常数得到的相位曲线实现0~250°的相位补偿,使得超材料实现在U波段的相位变化。仿真结果表明,通过将偏压从0增加到14V,超材料在52GHz时呈现250°的相移。此外,此超材料的谐振频率可从53.6GHz连续可逆地转移到49.9GHz。通过调节超材料液晶激励区域的介电常数即改变阵列单元的谐振特性,实现了相位补偿,为平面反射阵列天线的设计提供了一种新思路。
Voltage tunable metamaterial of short cross type array based on liquid crystal(LC)is proposed to achieve phase compensation at U-band frequencies.Simulation results show,by increasing bias voltage from 0 to 14 V,the metamaterial presents 250°phase compensation at 52 GHz.Moreover,the resonant frequency is continuously and reversibly shifted from 53.6 GHz to 49.9 GHz.By adjusting the permittivity of the LC excitation region of the metamaterial to change the resonance characteristic of the array unit,phase compensation is achieved,which provides a new method for the design of the planar reflect array antenna.
引文
[1]Smith D R,Pendry J B,Wiltshire M C K.Metamaterials and negative refractive index[J].Science,2004,305(5685):788-792.
[2]Zhu Jianfei,Jiang Wei,Liu Yichao,et al.Three-dimensional magnetic cloak working from D.C.to 250kHz[J].Nature Communications,2015,6:8931.
[3]Wang Pu,Slipchenko M N,Mitchell J,et al.Far-field imaging of non-fluorescent species with subdiffraction resolution[J].Nature Photonics,2013,7:449-453.
[4]Tyc T,Zhang Xiang.Forum optics:Perfect lenses in focus[J].Nature,2011,480:42-43.
[5]马宇,章海锋,刘婷,等.一种波束扫描超材料天线的设计[J].强激光与粒子束,2018,30:103206.(Ma Yu,Zhang Haifeng,Liu Ting,et al.Design of beam scanning metamaterial antenna.High Power Laser and Particle Beams,2018,30:103206.
[6]Farinelli P,Chiuppesi E,Maggio F D,et al.Development of different K-band MEMS phase shifter designs for satellite COTM terminals[J].International Journal of Microwave and Wireless Technologies,2010,2(3/4):1868-1871.
[7]Houzet G,Burgnies L,Velu G,et al.Dispersion and loss of ferroelectric Ba0.5Sr0.5TiO3thin films up to 110GHz[J].Applied Physics Letters,2008,93:053507.
[8]Bulja S,Mirshekar-Syahkal D,James R,et al.Measurement of dielectric properties of nematic liquid crystals at millimeter wavelength[J].IEEE Trans Microwave Theory and Techniques,2010,58(12):3493-3501.
[9]Yang Fuzi,Sambles J R.Resonant transmission of microwaves through a narrow metallic slit[J].Physical review letters,2002,89:063901.
[10]Yang Fuzi,Sambles J R.Determination of the permittivity of nematic liquid crystals in the microwave region[J].Liquid Crystals,2003,30(5):599-602.
[11]Ma Shuang,Yang Guohui,Erni D,et al.Liquid crystal leaky-wave antennas with dispersion sensitivity enhancement[J].IEEE Transactions on Components,Packaging and Manufacturing Technology,2017,7(5):792-801.
[12]Foo S.Liquid-crystal-tunable metasurface antennas[C]//11th European Conference on Antennas and Propagation.2017:16900604.
[13]Bildik S,Dieter S,Fritzsch C,et al.Reconfigurable folded reflect array antenna based upon liquid crystal technology[J].IEEE Trans Antennas and Propagation,2015,63(1):122-132.