A 60-GHz-band compact IQ modulator MMIC for ultra-high-speed wireless communication

A 60-GHz-band compact IQ modulator MMIC with a double-balanced mixer configuration is developed for ultra-high-speed wireless transceivers. The IQ modulator includes asymmetric baluns and an LO driver amplifier in a 2.5 mm x 1.15 mm chip to obtain differential signals in a CPW scheme and to mitigate the requirements for LO input power, respectively. The chip size of the CPW balun is markedly reduced by introducing CPS transmission lines in place of lambda/2-lines. When the fabricated modulator MMIC is operated as an SSB mixer, it shows a conversion gain of -11.1 dB at an LO input power of 0 dBm. Under the vector signal measurements, the fabricated modulator shows EVM values of less than 4 % and 5.5 % for QPSK and 16QAM at a symbol rate of 15 Msps in the carrier frequency range of 59 to 66 GHz.