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In this article, we propose a monostatic radiometry system for measuring the internal temperature of human tissue, while simultaneously performing radio frequency (RF) hyperthermia treatment. To demonstrate the adequacy of the proposed scheme, we present the results of experiments conducted on pork samples, which have a biological structure and electrical characteristics that are quite similar to those of the human body. We propose to use S‐band total power radiometry. The radiometry frequency was set at 3.85 GHz, with an operating bandwidth of 220 MHz, system gain of 66.95 dB, total system noise figure of 1.75 dB, and a sensitivity of 0.27 K. In order to prevent damage to the radiometry system, an RF switch and a low‐pass filter were added at the front‐end of the monostatic radiometry system to obtain sufficient isolation from the heating system. Using the skin, fat, and muscle tissue models, we performed both experiments and numerical simulations for a biological tissue model using a single dual‐band rectangular waveguide antenna operated at 5.725 GHz for microwave heating. In addition, we tested the proposed monostatic radiometry system in real‐time using pork samples, with an experimental setup capable of simultaneous microwave heating and radiometric temperature measurement. The system performance was verified by comparing the experimental radiometric results with the actual measured temperatures and simulation results.

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This paper proposes a measurement method of the complex relative permittivity of semi-solid materials using a new cavity structure. Semi-solid materials are positioned in the proposed cavity where an aperture exists on each corner of the upper part and a ground plane is separated. In order to show the validation of the proposed method, we measured the complex relative permittivity of distilled water and 0.9 % saline by sensing a shift of resonant frequency and using Critical-Points Method, and compared the results with those derived from the Cole-Cole equation.