Abstract: A quadrature modulator and an up-conversion mixer for an 802.11a wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology.A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the up-conversion mixer to improve its gain and increase the voltage swing.The measurement results show that the input P1dB achieves -3.6dBm,the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.

Key words: RFIC, CMOS technology, quadrature modulator, up-conversion mixer, Gilbert cell