Compact wideband five‐port reflectometer based on symmetrical waveguide ring junction for synthetic microwave imaging applications

Abstract

SummaryA compact and symmetrical five‐port reflectometer (FPR) for microwave imaging application is introduced in this paper. The proposed FPR shows a wide operational impedance matching bandwidth in the frequency span of 1.55–5.31 GHz (about 109.6%). It consists of three layers with a compact size of 42.4 × 42.4 × 3.2 mm3 and comprises five symmetric branch lines which were designed and optimized as a star junction topology and placed at the middle layer to realize an equivalent value of 70 dB for reflection coefficients at a center operating frequency of 2 GHz. Moreover, the measured results indicate that the FPR prototype has realized accuracies of approximately ± 120° in phase, 0.04 and 0.5 magnitudes of reflections and transmission coefficients, respectively, which are relative in parallel to the simulated and theoretical results. The proposed FPR proves higher efficacious capabilities to be used in microwave imaging for biomedical application systems.