L波段带双零点的窄带LTCC滤波器设计

An L-Band Narrow Band Filter with Double Zeros in LTCC Technology

本文应用LTCC技术设计了一个L波段二阶Chebyshev窄带带通滤波器。该滤波器集成在9层LTCC介质中,采用等效集总元件(电容电感)结构,充分利用LTCC的三维封装结构减小滤波器体积,通过谐振单元中集总元件的串并联产生两个带外传输零点,同时调整谐振单元耦合间距控制带宽。滤波器输入输出利用金属通孔将带状线过渡到微带上。滤波器(带过渡结构)的仿真结果为:中心频率1.42GHz,1dB相对带宽2.1%,插入损耗通带内最低0.5dB,回波损耗优于20dB,整个滤波器体积为:4.5×4×0.87mm3。

In this paper,an L band narrowband band-pass filter of Chebyshev-type with Low Temperature Co-fired Ceramic(LTCC)technology is proposed.The filter in nine substrate layers of Dupont 951 adopts the lumped-element inductors and capacitors in order to miniature the size of the filter.In order to realize the narrowband filter and produce two finite transmission zeros of the stop-band,lumped-elements in series and parallel are used.Coupling coefficient between the neighboring resonators is controlled by the coupling space.A broadband microstrip line to stripline transition is proposed in this paper too.The filter(with the transition) exhibits a simulation performance of a minimum insertion loss of 0.5 dB and return loss better than 20 dB in the passband,and the relative bandwidth of 2.1%at a center frequency of 1.42 GHz.