Compact Six-port Junction using Broadside-Coupled CPW Couplers for a Broadband Six-port Receiver

This paper presents the design and implementation of a wideband, compact six-port junction suitable for single-layer PCB technologies. It uses broadside-coupled coplanar waveguide (CPW) copulers to achieve compact size while maintaining good phase and amplitude imbalance from 1.5 GHz to 2.5 GHz. The q-points of the six-port junction show maximum measured phase and amplitude imbalance of +/- 10 degrees and 2.8 dB, respectively over the specified bandwidth. The proposed six-port junction is demonstrated to be used in a six-port receiver application. The proposed six-port receiver is shown to work between 1 GHz and 3 GHz. It is able to successfully demodulate up to 300 Mbps 64 QAM signals with a minimum EVM of 3.34%.