An Ultra Wideband (UWB) Mixer with 0.18UM RF CMOS Technology

In this paper a CMOS down-conversion mixer for UWB applications is presented. The mixer circuit, designed using a standard 0.18¿m RF CMOS technology, is an integral part of an entire UWB transceiver chip, working at the 3.1-10.6 GHz frequency range. The core of the mixer has been designed based on Gilbert cell architecture and uses a current injection method for increasing the linearity. For matching of RF and LO inputs to 50¿ a wideband matching circuit, using passive on-chip components, has been designed which provides a good match over the entire frequency range. A simple buffer is incorporated at the IF output. The simulated conversion gain of the mixer is greater than 10dB. The 1dB compression point, referred to input, is ¿10dBm and the IIP3 point is 4dBm. The RF return-loss is well below ¿10dB. Also, the LO-IF isolation is greater than ¿30dB, while the NF is about 10dB. The DC power consumption of the mixer is only 10mW. All characteristics are achieved for the entire frequency range of 3.1-10.6 GHz and meet the UWB standard requirements. In the paper it is shown that this mixer, which uses only a 1.8V supply, has considerable advantages over previously published mixers designed for this purpose.