Direct quadrature phase shift keying modulator using six-port technology

A direct quadrature phase shift keying modulator based on six-port technology is presented. The modulator comprises a six-port circuit, a switch matrix and open and short terminations. Using this modulator, direct phase shift keying modulation was achieved. Six-port technology has the advantage of signal integrity, low power consumption and physical scalability to attain different frequencies of operation and extendibility to M-ary phase shift keying. Experiment results demonstrate performance with an output phase difference from 0.8 to 4.5° and an amplitude difference from 0.5 to 2.7 dB. A data throughput of 200 Mbits was attained.