Abstract: A radio frequency (RF) receiver frontend for single-carrier ultra-wideband (SC-UWB) is presented. The front end employs direct-conversion architecture, and consists of a differential low noise amplifier (LNA), a quadrature mixer, and two intermediate frequency (IF) amplifiers.The proposed LNA employs source inductively degenerated topology. First, the expression of input impedance matching bandwidth in terms of gate-source capacitance, resonant frequency and target S₁₁ is given. Then, a noise figure optimization strategy under gain and power constraints is proposed, with consideration of the integrated gate inductor, the bond-wire inductance, and its variation. The LNA utilizes two stages with different resonant frequencies to acquire flat gain over the 7.1-8.1 GHz frequency band, and has two gain modes to obtain a higher receiver dynamic range. The mixer uses a double balanced Gilbert structure. The front end is fabricated in a TSMC 0.18-μm RF CMOS process and occupies an area of 1.43 mm². In high and low gain modes, the measured maximum conversion gain are 42 dB and 22 dB, input 1 dB compression points are -40 dBm and -20 dBm, and S₁₁ is better than -18 dB and -14.5 dB. The 3 dB IF bandwidth is more than 500 MHz. The doublesideband noise figure is 4.7 dB in high gain mode. The total power consumption is 65 mW from a 1.8 V supply.

Key words: radio frequency receiver front end, CMOS, low noise amplifier, inductively degenerated, single-carrier ultra-wideband