Wideband Six-Port Receiver using Elliptical Microstrip-Slot Directional Couplers

A prototype of a wideband six-port receiver is presented. It consists of three multilayer elliptical microstrips-lot directional couplers (MSDCs), a power divider and reactive-matching power detectors. To compose the receiver using MSDCs, a controlled-impedance via is required. The via, taken advantage of the multilayer structure, reaches a bandwidth of more than 190% and low insertion loss. 64-QAM signals with different data rates are fed for testing. From 0.5 GHz to 5 GHz the measured EVM is less than 4% with 1 Mbps data rate. The operation frequency covers many commercial standards and thus, the concept is suitable for cognitive radio application. A sensitivity of -52dBm and -58dBm is achieved at 0.9 GHz and 2.4 GHz, respectively, without LNAs.