Image-rejection receiver using on-chip active notch filters for 2.4-GHz band wireless communication applications

This paper presents the design and experimental results of image-rejection (IR) receiver front-end for 2.4-GHz band applications. The proposed IR-receiver front-end integrates a third-order active notch filter into each of conventional cascode low noise amplifier and down-conversion mixer to achieve high image-rejection ratio (IRR). The image signal is suppressed and the wanted signal is maximized due to series and parallel resonator effects of the notch filter, respectively. Consequently, the proposed IR-receiver front-end implemented in a standard 0.18 μm CMOS technology has the power gain of 21.5 dB, the noise figure of 3.5 dB, the input third order intermodulation product of −15 dBm and the IRR of 56 dB. The IR-receiver front-end dissipates a total of 5.5 mA from supply voltage of 1.8 V.