Design of a phase splitter for 3/sup rd/ ISM band

This paper describes the design of a differential phase splitter, which is used as a RF building block for the 3rd Industrial Scientific and Medial (ISM) band (5.1-5.9 GHz) Wireless Local Area Network (WLAN). Utilizing the concept of RC feedback, the circuit achieves a 180 degree phase difference and gain balance, without sophisticated tuning or compensation methods. With the use of Cadence Spectre RF Simulator and the 0.18 /spl mu/m CMOS Process Design Kit (PDK) from Chartered Semiconductor, the topology adopted in this paper is able to exhibit a gain of 2.93 dB to 3.57 dB within 5.1 GHz and 5.9 GHz. From a supply of 1.5 V, the circuit provides a phase error of 0.523 degree and a gain difference of 0.019 dB between its two output ports.