A Common-Mode Noise Suppression Filter for Gigahertz Differential Signals Based on Substrate Integrated Waveguide Resonators

Xiao-Lai Li,Guomin Yang,Qinzhuo Chen

doi:10.1109/access.2020.3025935

Xiao-Lai Li, Guomin Yang + Show 1 more

Open Access

https://doi.org/10.1109/access.2020.3025935

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Abstract

A common-mode noise suppression filter for microstrip differential lines based on substrate integrated waveguide resonator (SIWR) is proposed in this article. The proposed common-mode filter (CMF) consists of cascaded SIWR units with different size. The equivalent characteristic impedance circuit model of the proposed CMF is given to predict the common-mode suppression characteristics by introducing the spectral domain approach (SDA). Simulated results show that the common-mode noise is decreased more than 35 dB from 4.5 GHz to 11.4 GHz, and −30 dB rejection band is obtained in the frequency band of 4.3-15 GHz. Moreover, the insertion loss and the group delay in the frequency domain show that there is little degradation for differential signals. In the time domain, 86.5% amplitude suppression of common-mode noise is achieved. In addition, the eye diagrams in the time domain are investigated to explain the effectiveness of the proposed CMF and indicate that the CMF can maintain the differential signal integrity. The prototype is fabricated to verify the validity of the proposed structure, and the measurement results show good agreement with the simulation results.

Highlights

Differential signals have played an important role in the signal transmission of modern high-speed circuits
For further investigating the characteristic of the proposed common-mode filter (CMF), the equivalent characteristic impedance circuit model of the proposed CMF is given to explain the principle by using the spectral domain approach (SDA), and the group delay in the frequency domain and the eye diagram in the time domain are studied to prove the effectiveness of the proposed structure
A common-mode noise suppression filter for high-speed differential signals based on substrate integrated waveguide resonators (SIWR) is presented in this article

Summary

INTRODUCTION

Differential signals have played an important role in the signal transmission of modern high-speed circuits. Li et al.: Common-Mode Noise Suppression Filter for Gigahertz Differential Signals Based on SIWRs reach 87% and 118% in literatures [6] and [7], respectively. A common-mode noise suppression filter for high-speed differential signals based on substrate integrated waveguide resonator (SIWR) is presented. The fractional bandwidth of rejection band for the common-mode noise below −35 dB can reach over 86% and the common-mode noise suppression less than −30 dB can be obtained in the frequency band of 4.3-15 GHz. For further investigating the characteristic of the proposed CMF, the equivalent characteristic impedance circuit model of the proposed CMF is given to explain the principle by using the SDA, and the group delay in the frequency domain and the eye diagram in the time domain are studied to prove the effectiveness of the proposed structure. The values of Q4 and Q10 are given in literature [31]

CHARACTERISTIC IMPEDANCE OF BROADSIDE-COUPLED LINES

TWO CASCADED CMF UNITS ANALYSIS

FABRICATION AND MEASUREMENTS

Findings

CONCLUSION