2.4/5.7-GHz CMOS Dual-Band Low-IF Architecture Using Weaver–Hartley Image-Rejection Techniques

A 2.4/5.7-GHz dual-band Weaver-Hartley architecture, using 0.18-mum CMOS technology, is demonstrated in this paper. The 2.4-GHz signal is set to be the image signal when the desired signal is at 5.7 GHz, and vice versa. Since the Weaver and Hartley systems are combined into this architecture, the demonstrated architecture rejects not only the first image signal, but also the secondary image signal. The image-rejection ratios of the first image signal and the secondary image signal are better than 40 and 46 dB, respectively. In this paper, a diagrammatic explanation is employed to obtain the image-rejection mechanisms of the Weaver-Hartley architecture.