A 71∼86GHz, 2.5Gbps high performance millimeter-wave direct up-conversion quadrature modulator

An ultra-wide bandwidth and high performance up-conversion quadrature modulator operating at 71 GHz ~ 86 GHz has been designed based on OMMIC GaAs 0.2 ¿m pHEMT technology. The core circuit is the monolithic I-Q vector modulator employing two bi-phase cold-pHEMT amplitude modulators. By optimizing and tuning, the results show the excellent performance at the whole bandwidth. With no baseband predistortion, 64QAM modulation can be produced at 500 MBps with EVM better than 8%. The communication capacity can reach 2.5 Gbps except for some coding redundancy. To date, this represents the highest reported ability for direct multilevel carrier modulation using monolithic technology.