Design of 2.4-GHz CMOS reconfigurable dual-function switch network and its application on array beamforming

This paper proposed a 2.4-GHz monolithic switch network, which can be reconfigured with two functionalities, serving as a single-pole-quadruple-throw (SPQT) switch or a 3-dB Wilkinson power divider (PD). The circuit consists of numbers of MOS switches in order to select the desired signal path as well as to terminate the unused ports. In SPQT switch operation, the experimental results show that the insertion and return losses are 2 dB and >15 dB, respectively. For 3-dB Wilkinson PD operation, the measurements exhibit that, with all ports matched to 50 Ω, the return loss and the output ports isolation are better than 19 dB with an insertion loss of ~ 1.6 dB. This circuit is fabricated in 0.18-μm CMOS technology with chip size of 0.78 mm² (excluding the I/O pads). To demonstrate its applicability, an example of single/twin-fed Butler matrix driven by the proposed device for array beamforming is presented.