Broadband mm-Wave Current/Voltage Sensing-Based VSWR-Resilient True Power/Impedance Sensor Supporting Single-Ended Antenna Interfaces

• Published in: IEEE journal of solid-state circuits Vol. 58; no. 6; pp. 1535 - 1551
• Main Authors: Munzer, David, Mannem, Naga Sasikanth, Lee, Jeongseok, Wang, Hua
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antenna arrays; Antenna measurements; Antennas; Beamforming; Broadband; built-in-self-test (BiST); Coupling; Couplings; current/voltage sensing; Dynamic range; Error analysis; Frequencies; Impedance; Loaded antennas; Millimeter waves; multiple input multiple output (MIMO); Optimization; Performance measurement; phased array; power amplifiers (PAs); Power generation; power sensing error (PSE); power/impedance sensor; Sensors; Voltage; voltage standing wave ratio (VSWR); Voltage standing wave ratios; Wave fronts
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2022.3211935

High-performance RF/mm-Wavefront ends often require in situ sensing circuitries to monitor performance metrics and drive their built-in-self-test (BiST) algorithms for performance recovery or optimization. In large-scaled integrated phased-arrays, antenna coupling often results in dynamic beam-dependent impedance variations [antenna voltage standing wave ratio (VSWR)] and front-end degradation, necessitating in situ load-invariant power/impedance sensors. However, the state-of-the-art mm-Wave sensors only demonstrate sensing at a single frequency, instead of the entire frequency band of interest with limited accuracy over antenna VSWR. Therefore, we propose a broadband current/voltage sensing-based VSWR resilient true power/impedance sensor supporting single-ended interfaces using the GlobalFoundries 45 nm CMOS SOI process. Comprehensive theoretical analyses of the coupling mechanisms and analog multiplier architectures are presented. Sources of error for power sensing are highlighted in detail. At 34 GHz, the proposed sensor measures the power sensing error <inline-formula> <tex-math notation="LaTeX">(\text {PSE}) \le \pm 1 </tex-math></inline-formula> dB for 3:1 VSWR and ±0.5 dB for 2:1 VSWR. Over 22-41 GHz, the measured PSE is <inline-formula> <tex-math notation="LaTeX">\le \pm 3.4 </tex-math></inline-formula> dB for 3:1 VSWR and ±1.5 dB for 2:1 VSWR. In addition, the proposed sensor under a 50 <inline-formula> <tex-math notation="LaTeX">\Omega </tex-math></inline-formula> load demonstrates a maximum dynamic range of 22.89 dB at 42 GHz and a dynamic range <inline-formula> <tex-math notation="LaTeX">>21.46 </tex-math></inline-formula> dB over 27-41 GHz. At 33 GHz, the measured <inline-formula> <tex-math notation="LaTeX">\vert \Gamma \vert /\angle \Gamma </tex-math></inline-formula> errors are <inline-formula> <tex-math notation="LaTeX">\le 0.072 </tex-math></inline-formula>/7.3° for 3:1 VSWR and <inline-formula> <tex-math notation="LaTeX">\le0.04 </tex-math></inline-formula>/7.13° for 2:1 VSWR, while demonstrating <inline-formula> <tex-math notation="LaTeX">\vert \Gamma \vert /\angle \Gamma </tex-math></inline-formula> errors of <inline-formula> <tex-math notation="LaTeX">\le 0.2 </tex-math></inline-formula>/34° for 3:1 VSWR and <inline-formula> <tex-math notation="LaTeX">\le 0.11 </tex-math></inline-formula>/27° for 2:1 VSWR over the entire 27-41 GHz BW. The chip die occupies an area of 0.97 <inline-formula> <tex-math notation="LaTeX">\times1.99 </tex-math></inline-formula> mm and a sensor core area of 0.48 <inline-formula> <tex-math notation="LaTeX">\times1.66 </tex-math></inline-formula> mm.