A Full-Passband Linear-Phase Band-Pass Filter Equalized With Negative Group Delay Circuits

Zhongbao Wang,Hongmei Liu,Zhi Ning Chen,Te Shao,Shaojun Fang

doi:10.1109/access.2020.2977100

Zhongbao Wang, Hongmei Liu + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.2977100

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Abstract

A full-passband linear-phase band-pass filter (BPF) equalized with negative group delay circuits (NGDC) is proposed. The NGDCs are utilized to suppress the salient group delay at the edge of the passband of the traditional BPF for achieving the full-passband linear-phase characteristic. To obtain input- and output-port impedance matching, two BPFs loading NGDCs are center symmetrically configured by Wilkinson power dividers. To verify the design concept, a 3-order full-passband linear-phase BPF is designed and fabricated. From the measured results, the GD fluctuation is reduced by 74% from 0.57 to 0.15 ns, return loss is better than 10 dB, and the insertion loss variation is less than 3 dB within the frequency range from 2.142 to 2.804 GHz. The proposed BPF achieves a flat group delay in the whole passband and realizes the full-passband linear-phase characteristic.

Highlights

As an essential device in the microwave communication systems, the band-pass filter (BPF) has been researched more and more widely
In this paper, a full-passband linear-phase BPF equalized with negative group delay circuits (NGDC) has been proposed
The NGDCs are respectively loaded at the input and output ports of the traditional BPF to suppress the salient group delay at the edge of the passband of the traditional BPF

Summary

INTRODUCTION

As an essential device in the microwave communication systems, the band-pass filter (BPF) has been researched more and more widely. With the development of the negative group delay circuit (NGDC), it provides a new idea to achieve GD equalization that is utilizing the negative GD to cancel the positive GD [21], [22] Based on this thought, the NGDCs have been applied in increasing the bandwidth and the efficiency of the amplifiers [23], [24], eliminating the beam squint in the serially fed antenna array [25], improving the signal integrity [26], and realizing signal synchronization [27]. The Z1 should be chosen as high as possible to achieve a low insertion loss and the R1 and Z2 are adjusted to achieve the desired GD

DESIGN PRINCIPLE OF THE TRADITIONAL BPF

FULL-PASSBAND LINEAR-PHASE BPF EQUALIZED WITH NGDCS

Findings

CONCLUSION