Defrosting apparatus with low-loss load detection and methods of operation thereof

A thermal increase system, comprising:

• a radio frequency (RF) signal source configured to supply an RF signal to an electrode to cause the electrode to radiate RF electromagnetic energy;
• power detection circuitry configured to repeatedly measure RF power values of the RF electromagnetic energy to generate a plurality of RF power values;
• and
• a controller configured to determine that a load proximate to the electrode is a low-loss load based on a rate of change of the plurality of RF power values, and to determine one or more signal parameters of the RF signal in response to determining the load is the low-loss load.

A method, comprising:

• supplying, by a radio frequency (RF) signal source, one or more RF signals to a transmission path that is electrically coupled between the RF signal source and one or more electrodes that are positioned proximate to a cavity to cause the one or more electrodes to radiate RF electromagnetic energy;
• periodically measuring, by measurement circuitry, an RF power value of the RF signal along the transmission path, resulting in a plurality of RF power values;
• determining, by a controller, a rate of change of the plurality of RF power values;
• determining, by the controller and based on the rate of change, that a load in the cavity is a low-loss load;
• and
• modifying, by the controller, an operation of RF signal source in response to determining that the load is the low-loss load.