A New Configuration of a Microstrip 180° Hybrid Reconfigurable Coupler

Abstract

In this paper, we have studied the characteristics of a 180° microstrip hybrid coupler at 2.45 GHz. The primary objective of this study is to validate the various design steps associated with this circuit. We analyze the coefficients of transmission, reflection, isolation, and phase shift at the output. The final structure undergoes validation using two electromagnetic solvers—one based on the moments method and the other on the Finite Integration Technique. The simulation results are found to be consistent in terms of performance and S-parameters. The proposed structure is validated on planar technology and implemented on an flame retardant-4 substrate. After that we have integrate a tuning technique based on varactor diode biased in reverse mode which behaves as a variable capacitor permitting to obtain a reconfigurable 180 microstrip coupler. The tuning technique was validated into simulation by modeling the varactor by capacitor.