This thesis utilizes the TSMC 3P3M 0.35um SiGe technologies to design the front-end chip including Power Amplifier(PA)、Micromixer and transmitter for WLAN 802.11g and Wimax 802.16d System. The linearizer is added for PAs to satisfy high power and high linearity demands and the wideband matching have been designed to approach dual-band PA. A Gilbert micromixer is demonstrated in this paper ,the RF, LO, and IF ports of the micromixer are all single-ended using the on-chip active LO balun,we use transistor to get wideband matching. Finally,the differences between simulations and measurement results are addressed with some possible improvement directions.