An image-reject down-converter for 802.11a and HIPERLAN2 wireless LANs

An image-reject down-converter for IEEE 802.11a and ETSI HIPERLAN2 wireless local area networks was implemented in a low-cost 46-GHz-f _T silicon bipolar process. The circuit integrates a variable-gain low noise amplifier and a double-balanced mixer along with passive image rejection filters. It exhibits a 4-dB noise figure and a power gain of 23 dB. By reducing the low noise amplifier gain by 9 dB (thanks to a 1-bit gain control), the down-converter achieves an input 1-dB compression point of –14 dBm, while drawing only 23 mA from a 3-V supply voltage. The adopted filtering approach provides an image rejection ratio higher than 60 dB.