Intracavity directional microwave heating based on a single-source multifrequency phased array

Microwave directional heating is typically realized by the control of multi-channel solid-state sources, which increases both system complexity and cost. In this work, a dual-zoned heating method based on a single-channel solid-state source with a power-division feed network is proposed. By merely tuning the output frequency of the solid-state source, the heating target area can be switched to realize zoned heating. A one-part-nine power-division feed network cascaded by a coaxial line and a one-part-three power divider is designed to achieve heating in different target regions with a beam deflection of ±18° (total 36°) at 2.4 GHz for left zone and 2.5 GHz in two areas, respectively. A multiphysics field model is established to verify the feasibility of realizing frequency-controlled zonal heating, with 100 ml, 200 ml, and 250 ml water loads. The simulation results show that under three volume water loads, the temperature rise in the target area is approximately twice that of the non-target area. The experiment confirmed these results, with an average error of approximately 3.5°C. The system proposed in this paper provides a microwave directional heating system with simplified phase modulation processes and system configuration, paving the way for broader application of targeted heating technologies.