双频带通滤波器的优化设计

Optimized Compact Dual-band Bandpass Filter for WLANs

利用阶跃阻抗谐振器优化,设计了一个工作在无线局域网(2.4/5.2GHz)的双频带通滤波器。通过奇、偶模分析,在阶跃阻抗谐振器理论计算公式基础上,根据不同的阻抗比条件,阶跃阻抗谐振器谐振频率比与阶跃阻抗高、低阻抗电长度之比的关系曲线,可以方便地确定阶跃阻抗谐振器的谐振频率和电长度,通过sonnet电路仿真软件验证了设计的合理性,并给出了用于无线通信2.4、5.2 GHz双频带通滤波器的设计结果。该带通滤波器可以分别在2.4、5.2 GHz处得到较好的通带性。由于交叉耦合的存在,该双频带通滤波器在两个通带端各有一个传输零点,以此来提高滤波器的通带频率选择性。最后,测量结果与仿真结果基本吻合。

In this letter,a compact dual-band bandpass filter using stepped impedance resonators is optimized for WLAN（2.4/5.2GHz） applications.By analyzing odd-mode and even-mode and stepped impedance resonator formula,curves are got by matlab simulation.It is easy to design the electric length of SIRs and the dual-band frequency.It is also not difficult to optimize resonators circuit by using sonnet soft which gives designed results in 2.4/5.2 GHz wireless communication.The BPF has good dual-band passband performance at 2.4/5.2 GHz.Since the existing of the cross coupling,the dual-band BPF has two transmission zeros on either side of both passbands that improve the frequency selectivity of passband.Finally,the measured results validate the proposed design.