Design &Developement of Monolithic IQ mixer using UMS PH25 GaAs process at 5400±125 MHz

Design and development of a C band monolithic passive IQ mixer using $0.25 {\mu} \mathrm{m} -\mathrm{p}-$HEMT process of UMS foundry is presented here. In the Mixer design, power divider and rat-race coupler are based on lumped element approach to reduce the chip area, Quadrature hybrid is designed using power divider approach, where required phase difference obtained using equivalent lumped model of RH/LH transmission line at the output ports of power divider. This topology reduces the size of circuits at low frequency as well as provides wide bandwidth operation of hybrid. The on-wafer measurements of fabricated large production of MMIC mixer shows typical conversion loss of 13dB with 0.8 dB flatness over the RF frequency $5400 \pm 125$ MHz and IF frequency DC-125 MHz, along with LO to RF isolation better than 35 dB. The mixer was simulated, ruggedized for improved yield and tested at three different LO powers to ensure less sensitivity of mixer with temperature dependent LO power variation. The obtained yield is very good and 100% fabricated MMIC’s are fully functional and validates high production yield.