Ultra-Wideband Front-End With Tunable Notch Filter

Abstract

This paper presents the design of an LNA with integrated tunable notch filter targeted for UWB receivers. Impulse-based UWB systems suffer from an increased BER in the presence of strong interferers due to reduced SNR. The first stage of the LNA achieves a wideband input match while the second stage employs an integrated bridged-T filter for interferer cancellation. The LNA has been implemented in a standard 0.18mum CMOS process. Simulated results show the notch filter is tunable from 3.5GHz to 7.0GHz with greater than 40dB of rejection. For a notch frequency of 5.3GHz, the noise figure and gain at 3.5GHz are 4.1dB and 12.1dB respectively