Six-port demodulator in homodyne direct conversion receiver

Abstract

A six-port demodulator in homodyne direct conversion receiver is presented in this paper. The direct-IF or zero-IF conversion process is performed by several circuit designs in the demodulator such as six-port correlator and proposed power detector circuit. They are able to produce baseband signals and constellation diagram of QPSK operation. Six-port correlator contains double-stage Wilkinson power divider and quadrature coupler which employs wideband characteristics. Six-port demodulator is the best choice for replacing conventional mixer in Ultra-wideband (UWB) frequency range from 3.1 GHz to 10.6 GHz in homodyne architecture. The operating principle of proposed homodyne receiver and six-port demodulator results based on QPSK demodulation are presented and discussed in this paper.