Broadband reconfigurable matching network using a non‐uniform transmission line

Abstract

In this study, the authors propose the use of distributed elements interconnected with switches to construct a reconfigurable matching network (RMN). Several RMNs are constructed using tunable lumped elements. However, this technique increases the system complexity because of the use of digital-to-analogue converters and synthesis algorithms. In this study, the proposed RMN employs a non-uniform transmission line with adjustable characteristic impedances, which are controlled by opening or closing the switches. While previous studies on non-uniform transmission lines have aimed to investigate the fixed configurations, this topology is designed to be an RMN that satisfies the design challenges. The maximum dimension is 0.2 times the guided wavelength of the low operational frequency, and five switches are used; however, the matchable impedances cover an extensive range of the Smith chart, and the RMN successfully tunes inherently unmatched antennas to operate at a target frequency band that depicts a fractional bandwidth of 60%. Additionally, the evaluated results depict that the fabricated RMN illustrates low insertion loss and high transducer gain and that it achieves both antenna-mismatch compensation and antenna-bandwidth extension.