This paper presents the design of a single-chip FM transceiver at 935 MHz and a AQPSK transceiver at 2.45 GHz. The fully integrated FM transceiver design in standard 0.18μm CMOS process incorporates a transmit/receive switch, a single-ended input differential output low noise amplifier, differential input single-ended output power amplifier, an LC tuned quadrature voltage controlled oscillator, mixer, IF amplifier, a g m-C based oscillator and a chopper stabilized amplifier used for wireless sensor applications. The power output is about 50mW. The AQPSK transceiver design in standard 0.25 μm CMOS process incorporates a baseband input processor, a low frequency quadrature modulator, a quadrature RF VCO, an upconverter and a linear power amplifier.