A complex image rejection circuit with sign detection only

The orthogonal property of I/Q channels is applied to adaptively correct path gain and phase errors using four sign detectors. A complex baseband S/H chip achieves an image rejection of 65dB while sampling at 40MS/s. The chip occupies 0.8times0.45mm
²
in a 0.18μm CMOS process and consumes 23mW at 1.8V