基于耦合结构的W波段波导滤波器的设计
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摘要
设计了一款W波段矩形波导带通滤波器。滤波器为一个四腔折叠型交叉耦合结构,能够产生两个传输零点和四个反射极点。其中直接耦合是通过电感膜片实现的磁耦合,而交叉耦合是通过一段消失模波导实现的磁耦合。对所有耦合结构尺寸参数进行仿真和分析,调整两个传输零点的位置,在保证滤波器宽带宽特性的前提下,实现了阻带抑制的提高。使用微电子机械系统(MEMS)工艺完成了滤波器的加工并对其进行测试。测试结果显示,滤波器的中心频率为87.5 GHz,3 dB分数带宽(FBW)为8.3%,插入损耗小于2 dB,通带外3 GHz处低频带阻带抑制达到-27 dB,高频带阻带抑制达到-50 dB,与仿真结果总体上吻合良好。
A W-band rectangular waveguide bandpass filter was designed.The filter is a folded cross coupling structure with four resonant cavities,and can generate two transmission zeros and four reflection poles.The direct couplings are magnetic couplings implemented by inductive irises.The cross coupling is also magnetic coupling realized through a length of evanescent waveguide.All the dimension parameters of the coupling structures were simulated and analyzed to adjust the locations of two transmission zeros.The stop band suppression of the filter was improved under the precondition of ensuring the wide bandwidth characteristic of the filter.The filter was fabricated by the micro-electromechanical system(MEMS)process and was tested.The test results show that the center frequency of the filter is 87.5 GHz,the 3 dB fractional bandwidth(FBW)is 8.3%,and the insertion loss is less than 2 dB.At 3 GHz outside the band,the stopband suppressions in low frequency band and in high frequency band reach -27 dB and -50 dB respectively,which are in good agreement with the simulation results.
A W-band rectangular waveguide bandpass filter was designed.The filter is a folded cross coupling structure with four resonant cavities,and can generate two transmission zeros and four reflection poles.The direct couplings are magnetic couplings implemented by inductive irises.The cross coupling is also magnetic coupling realized through a length of evanescent waveguide.All the dimension parameters of the coupling structures were simulated and analyzed to adjust the locations of two transmission zeros.The stop band suppression of the filter was improved under the precondition of ensuring the wide bandwidth characteristic of the filter.The filter was fabricated by the micro-electromechanical system(MEMS)process and was tested.The test results show that the center frequency of the filter is 87.5 GHz,the 3 dB fractional bandwidth(FBW)is 8.3%,and the insertion loss is less than 2 dB.At 3 GHz outside the band,the stopband suppressions in low frequency band and in high frequency band reach -27 dB and -50 dB respectively,which are in good agreement with the simulation results.
引文
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[3]DUAN J P,ZHANG B Z,ZHANG A X,et al.Microfabrication of a dual mode rectangular waveguide filter[J].Microsystem Technologies,2016,22(8):2011-2016.
[4]WANG J L,ZHANG B Z,WANG X,et al.Dual-mode bandpass filters made by SU-8 micromachining technology for terahertz region[J].Eletronics Letters,2017,53(11):730-732.
[5]DING J Q,LIU D,SHI S C,et al.W-band quasi-elliptical waveguide filter with cross-coupling and source-load coupling[J].Electronics Letters,2016,52(23):1960-1961.
[6]SHANG X,PENCHEV P,GUO C,et al.W-band waveguide filters fabricated by laser micromachining and 3-D printing[J].IEEE Transactions on Microwave Theory and Techniques,2016,64(8):2572-2580.
[7]GUO C,SHANG X,LI J,et al.A lightweight 3-D printed X-band bandpass filter based on spherical dual-mode resonators[J].IEEE Microwave and Wireless Components Letters,2016,26(8):568-570.
[8]MENDOZA M M,REBENAQUE D C,MELCON A A,et al.Complex waveguide filter topologies employing inductive windows and dielectric objects[J].IET Microwaves,Antennas&Propagation,2014,8(15):1305-1312.
[9]CARCELLER C,SOTO P,BORIA V E,et al.Design of hybrid folded rectangular waveguide filters with transmission zeros below the passband[J].IEEE Transactions on Microwave Theory and Techniques,2016,64(2):475-484.
[10]SHANG X,WANG Y,NICHOLSON G L,et al.Design of multiple-passband filters using coupling matrix optimisation[J].IET Microwaves,Antennas&Propagation,2012,6(1):24-30.