Direct heating through patch antennas

A microwave heating apparatus comprising:

• a cavity arranged to receive a load;
• at least one microwave generator;
• at least two patch antennas coupled to the at least one microwave generator, wherein each of the at least two patch antennas is configured to radiate microwaves into a predefined direct heating zone within the cavity proximate the respective patch antenna;
• and
• a control unit configured to select energy levels for each of the at least two patch antennas,
• wherein the at least two patch antennas each include a patch element separated from a ground plane element with an air gap, and wherein the patch element is rectangular with a width ranging from 5 cm to 10 cm and a length ranging from approximately 5 cm to 10 cm.

A microwave heating apparatus comprising:

• a cavity arranged to receive a load;
• at least one microwave generator;
• at least two patch antennas coupled to the at least one microwave generator, wherein each of the at least two patch antennas is configured to radiate microwaves into a predefined direct heating zone within the cavity proximate the respective patch antenna;
• and
• a control unit configured to select energy levels for each of the at least two patch antennas,
• wherein the at least two patch antennas each include a patch element separated from a ground plane element with an air gap, and wherein the separation between the patch element and the ground plane ranges from approximately 5 mm to 10 mm.