2.45 GHz宽阻带高抑制腔体滤波器的研究设计

Research and Design of 2.45 GHz Cavity Filter with Wide Stopband and High Suppression

针对手持式谐波雷达发射机自身产生的谐波信号严重干扰接收到的探测目标谐波信号问题,该文设计了一种谐振器开路端加圆盘的结构,该结构能有效缩小滤波器体积和抑制高次谐振频率产生的寄生通带,并研究了圆盘半径、谐振杆长度、调谐螺钉长度和半径对腔体滤波器谐振频率的影响。结果表明,圆盘半径和调谐螺钉半径增大,则等效电容增加,谐振频率降低。忽略其他因数影响,随着谐振杆长度和调谐螺钉长度增加,等效电感增大,谐振频率降低。最后,利用HFSS软件优化设计了一款中心频率2.45 GHz、带宽0.1 GHz的腔体滤波器。测试结果表明,滤波器通带内插损小于1 dB,阻带为3~9 GHz内衰减优于90 dB,体积仅为51 mm×11 mm×27 mm,满足设计要求。

Aiming at the problem that the harmonic signal generated by the handheld harmonic radar transmitter itself seriously interferes with the received harmonic signal of the detection target,this paper designs a structure with a disc at the open end of the resonator,which can effectively reduce the size of the filter and suppress the parasitic passband generated by the high-order resonance frequency,and the influences of the radius of the disc,the length of the resonance rod,the length and the radius of the tuning screw on the resonance frequency of the cavity filter are studied.The results show that with the increase of the radius of the disc and the tuning screw increase,the equivalent capacitance increases,while the resonance frequency decreases.When the influences of other additional factors are neglected,the equivalent inductance increases and the resonance frequency decrease with the increase of the length of the resonance rod and the length of the tuning screw.Finally,a cavity filter with a center frequency of 2.45 GHz and a bandwidth of 0.1 GHz was optimized using HFSS software.The test results show that the insertion loss in filter passband is less than 1 dB,the attenuation in the stopband from 3 GHz to 9 GHz is better than 90 dB.The volume is only 51 mm×11 mm×27 mm,which meets the design requirements.