A 2.41 GHz ISM receiver using an IQ VCO-mixer

This paper presents an inductorless 2.41 GHz ISM receiver, implemented in a standard 130 nm CMOS technology. The receiver consists of a feedback LNA and an IQ VCO-mixer, designed for low area and low power. The VCO-mixer is based on an IQ cross-coupled RC relaxation VCO, where two single oscillators are coupled through active loads. This topology consumes approximately 20 % less power and reduces the area, in comparison to the commonly used soft-limiter coupling. The mixing function is incorporated in the IQ VCO, benefiting from an increased gain. The LNA is based on a shunt-shunt topology, where feedback is used for input impedance matching and gain desensitization. The LNA works both as RF signal amplifier and VCO-mixer´s current mirror, reducing a third of the total VCO-mixer´s power consumption. The receiver front-end has a gain of 22.26 dB and a noise figure of 7.98 dB, occupying an area of 0.145 mm² and consuming 7.58 mW from a 1.2 V power supply.