5/60 GHz $0.18~\mu m$ CMOS Dual-Mode Dual- Conversion Receiver Using a Tunable Active Filter for 5-GHz Channel Selection

A dual-mode dual-conversion receiver with two far-apart carrier frequencies, 5 and 60 GHz, and two very different channel bandwidths, tens-MHz and GHz, is demonstrated in a standard 0.18 μm CMOS technology. The dual conversion architecture receives 60-GHz mode using Schottky diodes at the first conversion stage and merges 5-GHz mode at the second conversion stage. The 5-GHz RF channel selection is achieved by inserting a 20-MHz bandwidth tunable active filter after a 5-GHz low-noise amplifier for the noise concern and before the second down-conversion mixer to relax the linearity requirement of subsequent stages. A tunable active filter with improved linearity using a transformer-coupled scheme is employed. As a result, the narrow 20 MHz channel bandwidth selection at 5-GHz mode shows a 500 MHz tuning range with noise figure of 9 dB and conversion gain of 28 dB. For 60-GHz operation, the 3-dB IF bandwidth is 1 GHz with noise figure of about 20 dB and conversion gain of -3 dB.