Wideband Chebyshev Impedance Transformer Set with Very Low Reflection Coefficient

Abstract

In various electronic and electrical devices for communication systems, impedance transformers with wide bandwidths are important. In this article, Chebyshev impedance transformers for ohmic loads with order 3 are presented at different frequencies and load impedance values using Duroid and FR4 substrates (εr = 2.2 and εr = 4.4 respectively). Simulated results are shown using the software Advanced Design System (ADS). The thickness of the substrate for FR4 dielectric material is 1.544 mm and for Duroid material is 1.27mm. The matching transformers were performed at 1 GHz, 1.5 GHz, 2 GHz, and 1.5 GHz for two load impedance 100 Ohms and 75 Ohms from 50 Ohms showing a reflection coefficient Γm = 0.05. The S11 scattering parameter was obtained.