Broadband and compact complex ratio measuring unit

Abstract

This study designs and analyzes Complex Ratio Measuring Unit (CRMU) and a Six-port Reflectometer (SPR) at a center frequency of 2.4 GHz. CRMU is designed using a compact size and wideband 3 dB-branch line coupler (BLC) and 3 dB-Wilkinson power divider with enhanced series-diamond stubs. The usage of these compact components leads to a compact size and improves the operating bandwidth. The idea of designing SPR is based on integrating a CRMU with 2 directional couplers along with isolator rather than a single BLC; to get a signal balance that enhances the quality of the reflection coefficient measurement. From the measurement result, it is found that the bandwidth of the CRMU and SPR is 1.7 GHz and the dimension of the CRMU is 60 × 45 mm. The proposed CRMU is fabricated using RT/duroid 5880 substrate with thickness of 0.38 mm. The dimension of the CRMU is 13 × 6.5 mm. The simulation and measurement results for both CRMU and SPR show good agreement.