A Single-Ended Coupler-Based VSWR Resilient Joint mm-Wave True Power Detector and Impedance Sensor

This letter presents the design of a coupler-based VSWR-resilient mm-wave joint impedance/true-power detector integrated together with a wideband power amplifier (PA) in a 45-nm CMOS SOI process. At 38 GHz, the sensor measures the antenna impedance for up-to 3:1 VSWR with a maximum |Γ| and ∠Γ error of 0.238° and 28.9°, respectively. The coupler network also measures the real power delivered to the standard 50- Ω antenna load with an error within ±0.5 dB for a 16-dB dynamic range, as well as sensing the real power delivered to a complex antenna load (up-to 3:1 VSWR) with less than ±3.35-dB error. The PA testbed has a 3-dB bandwidth of 37.5% (26-38 GHz) and OP1dB bandwidth of 36.3% (27-39 GHz). The PA achieves a peak Psat of 17.29 dBm, OP1 dB of 16.33 dBm, and peak PAE of 29.77% at 37 GHz. The PA with a sensor occupies an area of 1.31×1.36 mm
²
, while the sensor takes an area of 0.47×0.971 mm
²
. This work enables future built-in-self-testing (BiST) and in situ machine learning-based rapid performance optimization of mm-wave transmitter (TX) elements or TX arrays with element couplings.