High gain low noise folded CMOS mixer

A folded double-balanced mixer has been implemented in a 0.18 mum BiCMOS technology for wireless local positioning applications. Operating in the unlicensed ISM band centred at 5.8 GHz with a 150 MHz bandwidth and with a very low IF frequency band from 500 kHz up to 5 MHz, the mixer achieves 17 dB voltage conversion gain, 8.5 dB noise figure and input IP3 of - 6 dBm. The mixer power consumption is only 18 mW, excluding the output buffers, with 1.8 V supply voltage. These excellent results demonstrate the suitability of the folded mixer architecture for low power, wireless local positioning applications.