双/三模基片集成波导和共面波导混合结构滤波器设计

针对微波带通滤波器小型化、高性能的应用需求，提出使用双/三模方形基片集成波导和共面波导混合结构设计带通滤波器.通过改变双模基片集成波导中TE₁₀₂和TE₂₀₁的谐振频率和外部耦合的强弱，可实现具有近似椭圆、非对称和无传输零点响应的双模滤波器；两个相同尺寸的共面波导作为谐振器蚀刻在基片集成波导表面，与TE₁₀₂和TE₂₀₁共同形成一个通带，设计具有多样性响应的四阶滤波器.在具有非对称响应四阶滤波器的基础上，使主模TE₁₀₁频率移动到该通带附近，设计更宽带宽的五阶滤波器.并对设计的滤波器进行加工和测试.测试结果与仿真结果吻合，表明了该混合结构设计高性能滤波器方法的可行性.

Design of Filters Using the Hybrid Structure of Dual/Triple-Mode Substrate Integrated Waveguide and Ground Coplanar Waveguides

A class of planar bandpass filters (BPFs) using dual/triple-mode substrate integrated waveguide (SIW) resonator and ground coplanar waveguides (GCPWs) are proposed according to miniaturization and high selectivity.The quasi-elliptic,asymmetric and non-transmission zero (TZ) response dual-mode SIW filters can be realized by changing resonance frequencies of TE₁₀₂ and TE₂₀₁,and the external couplings.Two GCPWs of the same size are etched on SIW cavity top metal plane;and the TE₁₀₂,TE₂₀₁ and two GCPWs in a single SIW cavity are combined to construct the diversified response fourth-order filters.On the basis of asymmetric and non-TZ response,the fundamental mode TE₁₀₁ can be shifted to the passband to form a fifth-order filter with wider bandwidth.The designed BPFs were fabricated and measured;and the simulated and measured results agree with each other,demonstrating the feasibility of using hybrid dual/triple-mode SIW and CPWs in a single cavity to design BPFs.