一种小型化宽阻带发夹型微带滤波器的设计

Design of a Miniaturized Wide-stopband Hairpin Microstrip Filter

摘要:

本文提出了一种新型的小型化宽阻带发夹型滤波器设计，旨在克服传统微带发夹滤波器在设计频率倍频处遇到的寄生通带问题。通过在传统发夹型滤波器的输入输出端上增加3个1/4波长的开路微带线，有效抑制了寄生通带，同时采用交叉耦合的方式实现了整体器件的小型化。通过设计、加工和测试等步骤，完成了一个工作带宽为400 MHz，中心频率为3 GHz的带通滤波器，插入损耗为2.5 dB，同时实现对13 GHz以下频段寄生通带的有效抑制，带外抑制达到24 dB。本文所提出的新型滤波器结构简单，设计难度低，尺寸仅为23 mm×27.7 mm，满足当前通信领域对高性能、小型化滤波器的需求，展现了良好的应用前景。

Abstract:

This paper introduces a novel design for a miniaturized wide-stopband hairpin filter that aims to overcome the challenges of parasitic passbands at the harmonic frequencies encountered in traditional microstrip hairpin filters. By incorporating three 1/4-wavelength open-circuit microstrip lines at the input and output of the conventional hairpin filter, the design effectively suppres-ses parasitic passbands. Additionally, the application of cross-coupling techniques facilitates the miniaturization of the device. The design, fabrication, and testing phases culminated in the development of a bandpass filter with a 400 MHz bandwidth and a center frequency of 3 GHz. The filter demonstrates an insertion loss of 2.5 dB and achieves effective suppression of parasitic passbands below 13 GHz, with an out-of-band suppression of 24 dB. The new filter design is characterized by its simplicity and low complexity, with dimensions of just 23 mm by 27.7 mm, meeting the current demands in the communications field for high-performance, miniaturized filters, and demonstrating significant potential for future applications.