Active antennas in medical microwave radiometry

The use of active antennas in microwave radiometric thermometry is investigated, where prospective applications are within biomedical diagnostics. By incorporating a tiny low-noise amplifier, with only marginal self-heating, in the antenna probe, it is shown that the temperature accuracy of a broadband radiometer can be improved as a consequence of a smaller overall system noise figure. Proof of concept is verified experimentally through increased detectability of a hot object within a lossy medium.