A balanced vector modulator for LMDS applications

The design and performance of a monolithic microwave I-Q type vector modulator operating at 26 GHz is presented. The MMIC chip which measures 1.75 mm /spl times/ 2.1 mm, employs direct carrier modulation to reduce hardware complexity and cost. The static constellation was obtained with swept bias voltage control, with this, modulation of 16-quadrature amplitude modulation (QAM) is demonstrated. Baseband input levels were applied at 2.5 MSample/s, by an arbitrary waveform generator to demonstrate a 10 Mbits/s data rate transmitter operating at 26 GHz.