Abstract
In this thesis, two CMOS RF front-end circuits are proposed for WiMAX applications. These circuits are realized in TSMC 0.18 um 1P6M CMOS process technology can be applied to direct conversion receivers for high integration. For the first RF front-end circuit, the negative-resistance loading are used to increase the gain and the noise performance. Moreover, there is a DC-offset cancellation loop to solve the DC-offset problem. According to the measurement results, the RF front-end has a voltage conversion gain (CG) of 11 dB, a 1-dB gain compression point (P1dB) of -27.5 dBm, an input third-order intercept point (IIP3) of -14 dBm, an input second-order intercept point (IIP2) of 23 dBm, and a noise figure (NF) of 6.13 dB. The power consumption is 35.3 mW from a 1.8 V supply and its area is 1 mm2. With the help of the DC-offset cancellation loop circuits, the output DC-offset is smaller than 6 mV and the IIP2 improvement is 6dBm. For the second circuits, a flicker-noise reduction circuit is added to increase the low-frequency noise performance. The simulation results show that this RF front-end has a voltage conversion gain of 33.68 dB, a 1-dB compression point of -33.7 dBm, and a flat noise figure curve. From the simulation results, the improvement of NF at 10 KHz is 13.8 dB. It dissipates 33.1 mW from a 1.8 V supply.