小型化宽频带宽阻带微带滤波器的设计

Design of a Miniaturized Wideband Microstrip Filter with Broad Stopband

目前研究宽频带微带滤波器的文献很多,但普遍不能同时具有宽频带和宽阻带的性能,且带内回波损耗大,带外抑制差。为此,提出了一种新型的宽频带微带滤波器。该滤波器采用在E型阶跃阻抗谐振器(SIR)中引入U型结构的方法,实现其宽频带宽阻带的性能。对滤波器进行仿真、加工与实测,仿真结果与实测结果吻合良好。加工得到的滤波器3 dB带宽为7.1 GHz,低于-20 dB的高频阻带为9.3 GHz,带内回波损耗低于-23.2 dB,实物尺寸为15 mm×8.5 mm,具有小型化的特点。实测数据表明,提出的滤波器具有良好的性能,在工程领域具有实际的应用价值。

At present,there are lots of literatures for wideband microstrip filter research,but they generally can not have both wide band and wide stopband performance,and their band return loss is large and band rejection is poor. This paper presents a novel wideband microstrip filter in which the U-shaped structure is introduced to the E- shaped stepped impedance resonator（ SIR） to achieve wideband and wide stopband performance. The microstrip filter is simulated,fabricated and measured. The simulation results are in good agreement with the experimental results. The final filter＇s 3 dB bandwidth is 7. 1 GHz,less than -20 dB stopband bandwidth is 9. 3 GHz,and the return loss is less than -23. 2 dB,its size is 15 mm × 8. 5 mm, which has the characteristics of miniaturization. Measured data shows that the proposed filter has good per-formance so that it will have practical applications in engineering.