A high gain ultra-wideband low noise amplifier with 802.11a interference rejection

Abstract

A high gain ultra-wideband (UWB) low noise amplifier (LNA) with notch filter for 5.8 GHz interference rejection is presented in this paper. For extending the bandwidth with a considerably gain flatness, the UWB LNA uses the stagger tuning technique of two stages with different resonant frequencies. The notch filter with extremely high quality factor provides high rejection ratio to eliminate the in-band interference from nearby wireless local area network systems. The proposed circuit was simulated with TSMC 0.18 μm 1P6M CMOS process technology with 1.8 V power supply. The maximum power gain is 15.43 dB. The minimum noise figure is 4.36 dB with full bandwidth of 3.1-10.6 GHz. The input reflection coefficient S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> and the output reflection coefficient S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">22</sub> are both less than -10dB. The maximum interference rejection ratio (IRR) is over 44.7 dB at 5.83 GHz of interference. The chip size including I/O pads for further measurement is 0.877×0.985mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .