全可调高性能带通滤波器的小型化设计

A miniaturization of the adjustable high performance bandpass filter design

随着现代无线通信的高速发展,现代可重构射频前端往往需要融合多种无线信道和通信标准,传统的调谐滤波器由于无法同时自由调节带宽和中心频率,不能适应现代无线通信系统的要求[1]。因此中心频率与带宽同时可调的滤波器成为如今滤波器研究和发展的一个研究热点。近年来国内外在全可调带通滤波器的研究上有很大的进步,但是普遍都存在带宽和中心频率不能同时可调的情况、带外抑制比较低和带内损耗比较大的问题。本设计基于多模谐振器的结构,设计一个带宽和中心频率全可调的带通滤波器,且创新性的在输入端并联一个高Q电感,使得通带外引入了一个可调的传输零点。仿真结果显示,该滤波器在1~3 GHz频带内中心频率和带宽全可调,可调相对带宽为7.5%~100%,带内损耗小于0.5 dB,带外抑制大于16 dB,且滤波器采用多折线结构,电路尺寸仅为27 mm×18 mm,适合于各种微波集成电路或系统等。

With the high-speed development of modern wireless communication,fusion modern reconfigurable rf front-end often require a variety of wireless channel and communication standards,the traditional tuned filter unable to freely adjust bandwidth and center frequency at the same time,can not adapt to the requirements of the modern wireless communication system[1].So the center frequency and bandwidth tunable filter become now filter at the same time,a research focus in the research and development.In all the tunable band pass filter at home and abroad in recent years the research has the very big progress,but generally have bandwidth and center frequency can not adjustable,low restraint outside the band and the condition of the in-band loss bigger problems.This design based on multi-mode resonator structures,to design a full bandwidth and center frequency tunable band pass filter,and innovative in input a high Q parallel inductance,makes the passband outside the introduction of an adjustable transmission zeros.The simulation results showed that the filter within 1~3 GHZ frequency band center frequency and bandwidth fully adjustable,adjustable relative bandwidth is 7.5%~7.5%,with loss is less than 0.5 dB,is greater than 16 dB,restraint outside the band and filter using multiple line structure,circuit size is only 27 mm×18 mm,suitable for all kinds of microwave integrated circuits or systems,etc.