A Frequency Multiplexing Patch Antenna Array for Space Selectable Microwave Heating

Space-selectable microwave heating is a new trend of customized heating at present and in the future. Controllable antenna array (CAA) can effectively achieve space-selectable heating, which has drawn wide attention. In this article, a novel CAA approach of frequency multiplexing patch antenna array (FMPA) is proposed, with which the constituted patch elements have totally different resonant frequencies and each patch element exclusively takes charge of the heating task for certain subarea of entire planar area under heating. An all-metal four-element FMPA is designed as an example. It is integrated with a metal chamber where the target heating area is enclosed. Simulation results verify that the proposed FMPA has the function of independent space-selectable heating. Then, a controllable microwave heating system is built for the subsequent heating experiment. The experiment shows that, after the corresponding patch element being activated, the coverage ratio of each target heating subarea is more than 90%, and the error ratio is less than 1.5%. The proposed CAA technique of the FMPA enjoys vast potential in customized heating applications that has higher requirements for resolution of the subareas under heating. Its advantages include low cost, low loss, and high space utilization rate.