Generalized Design Technique of Ultra-Wideband Transitions for Quasi-TEM Planar Transmission Lines Based on Analytical Models

Gwan Hui Lee; Sachin Kumar; Wahab Mohyuddin; Hyun Chul Choi; Kang Wook Kim

doi:10.1109/ACCESS.2021.3069870

IEEE Access (Jan 2021)

Generalized Design Technique of Ultra-Wideband Transitions for Quasi-TEM Planar Transmission Lines Based on Analytical Models

Gwan Hui Lee,
Sachin Kumar,
Wahab Mohyuddin,
Hyun Chul Choi,
Kang Wook Kim

Affiliations

Gwan Hui Lee: ORCiD; School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, South Korea
Sachin Kumar: ORCiD; School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, South Korea
Wahab Mohyuddin: ORCiD; Research Institute for Microwave and Millimeter-Wave Studies, National University of Sciences and Technology, Islamabad, Pakistan
Hyun Chul Choi: ORCiD; School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, South Korea
Kang Wook Kim: ORCiD; School of Electronic and Electrical Engineering, Kyungpook National University, Daegu, South Korea

DOI: https://doi.org/10.1109/ACCESS.2021.3069870
Journal volume & issue: Vol. 9
pp. 52619 – 52633

Abstract

Read online

A generalized design technique of ultra-wideband planar transitions using EM-based analytical models is presented in this paper. Among various planar transmission lines, each transmission line has unique advantages over other line types, and a microwave component in a system can be designed to perform much better if it is implemented on a certain type of transmission line. Therefore, low-loss and high-performance transitions between transmission lines, with easy integrability with the main circuit board, are needed. The proposed transition design technique uses the Schwarz-Christoffel transformation, which is one of conformal mapping methods, and can be applied to design any planar transition between a pair combination of planar transmission lines based on TEM or quasi-TEM waves. To optimally match the characteristic line impedance and smoothly transform the electromagnetic field distribution between the planar transmission lines, entire cross-sections through the planar transition should be analyzed with proper models. In this paper, the cross-sections of planar transitions are categorized into 4 cross-sectional models, where each cross-section is divided into multiple regions for the analysis to obtain line capacitance. Therefore, for the 4 cross-sectional models, 7 types of basis structures are identified to obtain their capacitances by applying conformal mapping. By adding capacitances of a combination of the 7 analysis types, the total line capacitance, thus the characteristic line impedance, of any cross-sectional model of the planar transition can be obtained. The characteristic line impedance of each cross-sectional model calculated with the proposed analytical formulas is compared with the 3D EM calculations, and it is found that the deviated values are mostly well under 6%. This proposed technique enables to design various planar transitions efficiently and quickly for the maximum performance without parameter tuning trials, by providing optimal impedance matching and smooth field transformation up to mm-wave frequencies.

Published in IEEE Access

ISSN: 2169-3536 (Online)
Publisher: IEEE
Country of publisher: United States
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering
Website: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=6287639

About the journal

Abstract

Keywords