It’s a direct voltage readout method that uses the diode voltage and temperature relationship. Figure 1 Here’s the block diagram of a step-down converter that uses the PG N-channel MOSFET body. Source ...

The operated diodes block the “disconnected antennas” by about 30 dB. Signal losses at the closed diode is negligible. The signal to noise ration of the receiver deteriorates somewhat up to 1 dB.