基于非对称SIR的小型化双频带带通滤波器设计

Compact Dual Band-Pass Filter Design Using Asymmetrical Stepped-Impedance Resonators

为了实现移动基站的小型化双频带带通滤波,基于非对称阶梯阻抗谐振器(SIR),提出了两个通带中心频率和带宽均可调节的小型化双频带带通滤波器的设计方法,设计并制作了用于移动基站的0.9 GHz和1.8 GHz的双频段滤波器,测试结果与设计原理符合.该滤波器由2个加入了内部准集总短截线的开放式SIR组合而成,并由它们谐振产生2个不同的通带,其中第1个通带中心频率只取决于外部SIR的参数尺寸,而第2通带中心频率则要同时取决于外部SIR和准集总短截线的参数尺寸.最后设计制作了一个工作在移动基站0.9 GHz和1.8 GHz的双频带带通滤波器,其滤波器尺寸为24.76 mm×13.5 mm,并对其性能进行了测试.实验结果表明,仿真S参数和测量结果符合良好,从而验证了这种设计方法的有效性.

A compact dual-band bandpass filter was designed and developed based on asymmetrical stepped impedance resonators （SIR） for the realization of miniature dual-band bandpass filtering in mobile base station. The two central passband frequencies and bandwidths of the proposed filter can be adjustable by geometric parameters. A folded stepped impedance resonator modified by adding an inner quasi-lumped SIR stub was used as the basic module of a new configuration of dual-band bandpass filter to produce two different passbands. The first pass-band of the filter only depends on the dimensions of the external SIR, while the second passband depends on both the external SIR and the quasi-lumped stub. A dual-band filter operating at 0.9 GHz and 1.8 GHz was designed, fabricated and measured for the appli- cation of mobile phone base stations. The dimension of the proposed filter is 24.76 mm × 13.5 mm. The experimental results show that the measured S parameter fits very well with the simulation. The effectiveness of the proposed design method was validated.