A BPSK modulator using a ring-hybrid and HFET switches

摘要

A binary phase-shift keying(BPSK) modulator using a microstrip ring-hybrid and HFET switches is proposed here. The fabricated BPSK modulator works from 3.2GHz to 3.5GHz with output amplitude balance less than 1dB and phase balance within 2° of ideal 180°. Its conversion loss is around 6.7dB and relative flat across this frequency range. Around its center frequency, the amplitude balance is less than 0.1dB and the phase balance is almost ideal 180°. This results in a perfect squarewave modulation spectrum with carrier suppression over 40dB and spurious suppression over 33dB. The fabricated modulator has better power performance than the previously-published modulators.