一种双频带独立可调带通滤波器的设计

Design of a bandpass filter with independently tunable dual-band

提出一种新型的、中心频率可独立调谐的双频带通滤波器(bandpass filter,BPF).该滤波器由加载双端短路枝节的阶梯阻抗谐振器(stepped-impedance resonator,SIR)和双模开口环谐振器构成.二者共用输入输出耦合线,产生额外的传输零点,提高了滤波器的选择性.通过奇偶模的分析方法,在谐振器末端加载变容二极管,以调节奇偶模谐振频率来达到电调的效果.结果显示,第一通带的可调范围为1.93～2.20 GHz,第二通带的可调范围为2.78～3.10 GHz.比较仿真与测试结果,证明了该方法的有效性.

A dual bandpass filter （BPF） with two center frequencies tuned asynchronously and independently is presented. The proposed filter consists of a stepped-impedance resonator （SIR） with two-terminal shorted stubs and a dual-mode open-loop resonator. To generate additional transmission zeros and improve frequency selectivity, the common input and output coupling lines are used for these two structures. Using the odd-even mode analysis method, resonant frequencies of odd-even mode are electrically tuned due to the loaded vaxactors at the end of transmission line. The measured performance shows that the first passband can be tuned in a frequency range of 1.93-2.20 GHz, whereas the second passband varies from 2.78 to 3.10 GHz. Comparisons of simulated and measured results show effectiveness of the method.