Broadband three-mode balanced band-pass filter based on interdigital multi-mode resonators

Abstract

The invention discloses a broadband three-mode balanced band-pass filter based on interdigital multi-mode resonators, comprising a dielectric substrate, an input port feeder, a first output port feeder, a second output port feeder, a first interdigital multi-mode resonator and a second interdigital multi-mode resonator which are arranged on the upper surface of the dielectric substrate, and a metal grounding plate which is disposed on the lower surface of the dielectric substrate. The first interdigital multi-mode resonator and the second interdigital multi-mode resonator are respectively disposed at the two sides of the input port feeder, and are symmetrical stub-loaded multi-mode resonators. The broadband three-mode balanced band-pass filter of the invention has the characteristics of wide stop band, miniaturization, high common-mode rejection, high selectivity, low loss, and the like, and is very suitable for modern wireless communication systems.

Description

technical field [0001] The invention relates to the technical field of microwave passive devices, in particular to a broadband balanced bandpass filter based on a cross-type multimode resonator. Background technique [0002] In recent years, with the development of Modular Building Block (MBB) and Monolithic Microwave Integrated Circuit (MMIC), low cost, high integration, and miniaturization have become an important part of the integrated design of modern wireless communication systems. very important consideration. The balanced filter is an independent microwave passive device. Compared with the single-port filter, it has higher environmental noise immunity, better dynamic range, and lower electric field interference. Therefore, it plays an extremely important role in the construction of modern high-speed wireless communication systems. It functionally realizes the differential mode signal transmission in the passband range of the radio frequency circuit, and the common m...

AI Technical Summary

Problems solved by technology

Although the design theory of this design method is relatively simple, because the structure needs to be loaded with lumped elements, the structure processing is complicated and the error increases

The bandwidth of the balanced filter designed from the outside is relatively narrow, and the 3dB relative bandwidth is only 8.92%

[0005] In 2012, Wenjie Feng and Wenquan Che were in IEEE Transaction. Microwave Theory Technique (vol.60, no.6, pp.1560-1568, 2012) published "Novel Wideband Differential Bandpass Filters Based on T-Sharped Structure", proposing a T-shaped structure to achieve balanced signal output and dual Although the structure of this design method is relatively simple, the common-mode rejection effect is only 14.5 dB, and the differential-mode out-of-band rejection is poor.

However, the common mode rejection is only limited to the corresponding differential mode frequency band, and the out-of-band rejection of both common mode and differential mode is poor, and the insertion loss is large

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