Enhanced measurement sensitivity using near-field antenna with MMIC low-noise amplifier for deep tissue microwave thermometry

• Published in: IEEE sensors journal 2023-08, Vol.23 (15), p.1-1
• Main Authors: Issac, Jeslin P, Arunachalam, Kavitha
• Format: Article
• Language: English
• Subjects: Active antenna; Amplifiers; Antenna design; Antenna measurements; Antennas; Bandwidths; Design optimization; Design parameters; Dicke radiometers; Ground plane; High gain; Impedance matching; Integrated circuits; low-noise amplifier; measurement sensitivity; Microwave antennas; Microwave circuits; Microwave measurement; Microwave radiometers; Microwave radiometry; MMIC; MMIC (circuits); Near fields; Noise levels; Noise measurement; Patch antennas; Performance enhancement; Radiometers; Receivers & amplifiers; S parameters; Sensitivity enhancement; switch-circulator radiometer; Temperature measurement; Thermometry; tissue thermometry
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2023.3288274

A monolithic microwave integrated circuit (MMIC) low-noise amplifier (LNA) is incorporated in a passive antenna for non-invasive deep tissue thermometry using near field microwave radiometer. An internally impedance matched high-gain (30 dB) monolithic microwave integrated circuit (MMIC) LNA with 1 dB noise figure (NF) is integrated on the ground plane of a multi-layered microstrip patch antenna with a 1.27 mm thick superstrate. The antenna design parameters were optimized for non-invasive power reception with a sensing depth of 40 mm, return loss ≥ 30 dB at 1.3 GHz, and a -10 dB bandwidth of 200 MHz. A 1.3 GHz switch-circulator single reference Dicke radiometer with 200 MHz bandwidth was implemented to assess the performance of the active antenna. Microwave circuit simulations were used to optimize the scattering parameters, gain, and NF of the radiometer for unconditional stability. The fabricated microwave radiometer has 38 dB gain, 2.6 dB NF, and input and output port return loss greater than 15 dB over 1.2-1.4 GHz. Radiometer measurements of temperature-controlled tissue phantom indicate improved measurement accuracy with sensitivity of ±0.18°C for the proposed active antenna. Enhanced performance observed with the integration of MMIC LNA in the passive antenna is expected to improve non-invasive detection of deep-tissue temperature.