Highly Linear RMS Microwave Power Sensor Joule-Heating-Based Using CMOS Technology

This article presents the design and implementation of a high-power handing capacity, wideband, and excellent microwave-dc linearity root-mean-square (rms) microwave power sensor (PS) in 180-nm standard RF CMOS technology. The detection technique utilizes two well-matched microwave power absorbers and a balanced Wheatstone full bridge (WFB) with thermistors to produce a dc output proportional to incident microwave power. The lateral spacing between the hot and cold zones of WFB with 80, 100, 120, 140,and
$160 {\mu }\text{m}$
has been investigated experimentally, which provides insight into the proper adjustment of the layout parameters. The experimental result of the vector network analyzer (VNA) shows that the input reflection loss is less than −22.3 dB in the frequency range of 0–20 GHz. This indicates that the designed microwave PSs have good impedance matching characteristics. Moreover, it is demonstrated that the inherent linear relationship between the output dc voltage and the incident microwave power is less than 1.6% over a dynamic range of 1–500 mW. The proposed microwave PS can be further integrated in
${X}$
-band RF transceivers, offering high microwave-dc linearity, acceptable sensitivity, small size, and low cost for improving power transfer efficiency and optimizing the performance of the transmitting and receiving chain.