基于1/4步阶阻抗谐振器设计之微小化宽带带通滤波器设计

Miniaturized Wideband Bandpass Filter Design Using 1/4 Step Impedance Resonator Design

本文提出了一种微小化宽带带通滤波器。该滤波器由两个四分之一波长的步阶阻抗谐振器混合耦合组成,可以实现中心频率为2.2 GHz,具有1.5~2.9 GHz的通带和64%的带宽。为了验证设计理论,制造并量测滤波器,从量测结果看,通带内插入损耗为S21=-1.5 d B,回波损耗均大于-10 d B,通带群延迟在0.01~0.15内。在频带上边4.2 GHz的地方出现传输零点,提高了滤波器的选择性,整个电路尺寸约为21 mm×5 mm,即0.25λg×0.06λg,λg是2 GHz的波导波长,同时测量结果也显示出与模拟结果的良好一致性。

In this paper,a miniaturized wideband bandpass filter is proposed. The filter consists of two quarterwavelength stepped impedance resonators,achieving a center frequency of 2. 2 GHz,a passband of 1. 5 to 2. 9 GHz,and FBW is 64%. In order to verify the design theory,the designed filter is manufactured and measured.The measured results show that the insertion loss in the passband is S21=-1.2 d B,the return loss is greater than-10 dB,and the passband group delay is within 0.15 ns. The transmission zero occurs at 4.2 GHz above the frequency band,which improves the selectivity of the filter. The overall circuit size is about 21 mm×5 mm,which is0.25 λg×0.06 λg,λg is the waveguide wavelength of 2 GHz,and the measurement results are also matched with with the simulation results.