基于SIR的X波段小型化带通滤波器设计

Microstrip SIR filter has found wide application in microwave circuit with the advantages of compact size, low cost, easily integrated and far parasitic passband. In this paper, both the fundamental theory of microstrip SIR filter and the universal design method for coupled-resonator circuits are introduced. Because of high performance filter' complicated structure and large dimension, a miniaturized spilt-loop SIR bandpass filter worked at X band is designed and developed based on the fundamental theory .Furthermore, the software HFSS is used to simulate this filter for achieving the optimization goal. The proposed filter, whose total size is only 19mm×8.5mm(0.96λg×0.43λg), is designed and fabricated with RO4003 substrate, with a relative dielectric constant of and a thickness of 0.508mm. Simulation and measured results show that the filter has the characteristic of low insertion loss, high selectivity and perfect out-of-band rejection. It has the portability and engineering value simultaneously.