基于耦合传输线多陷波超宽带滤波器的设计

Design of Multiband Notched UWB Filter Based on Parallel-Coupled Line

为滤除窄带信号对超宽带通信系统的干扰,提出了一款具有多陷波特性的超宽带滤波器。采用λ/4平行耦合线构造结构紧凑的滤波单元节,并通过单元节级联的方式实现三陷波特性。将扇形枝节接入短路枝节匹配线,有效抑制了高次谐波。将环形谐振腔引入带阻单元,获得了良好的矩形系数。该滤波器的体积仅为25.5 mm×49.9 mm×0.6 mm,结构紧凑。仿真结果显示:滤波器的工作带宽为3~10 GHz,三个陷波频段为3.5~3.6 GHz、5.7~5.9 GHz和7.9~8.1 GHz,有效滤除了WiMAX(3.3~3.6 GHz)、WLAN(5.7~5.8 GHz)以及X波段卫星通信系统(7.9~8.4 GHz)的干扰。该滤波器通带内插入损耗较小且带外谐波抑制良好,抗干扰能力强,适用于各种超宽带系统。

To eliminate the interference of narrow band signals to UWB communication systems,an UWB filter with multiband notched property is proposed.The triple band notched characteristics are achieved by cascading the compact filter unit sections composed ofλ/4 parallel coupled lines.The higher harmonics are effectively suppressed by connecting the fan-shaped branch with the short-circuit branch matching line and the excellent rectangular coefficient is obtained by embedding a ring resonator into the band-stop unit.The proposed filter has a compact volume of 25.5 mm×49.9 mm×0.6 mm.Simulated results show that the filter has bandwidth of 3-10 GHz,it realizes band-notched characteristics of triple stop-bands at 3.5-3.7 GHz,5.7-5.9 GHz and 7.9-8.1 GHz,and efficiently rejects the jamming from WiMAX(3.3-3.6 GHz),WLAN(5.7-5.8 GHz)and X-band(7.9-8.4 GHz)satellite communication system.The filter exhibits small pass-band insertion loss and excellent out-of-band harmonic rejection and preferable anti-jamming ability,making it suitable for all kinds of UWB communication system.