Study on Improving Microwave Heating Uniformity Based on Phase-Frequency Simultaneous Modulation Technique

TL;DR

This paper introduces a phase-frequency simultaneous modulation technique to improve microwave heating uniformity by expanding the locking bandwidth of magnetrons, validated through numerical and experimental results.

Contribution

It presents a novel injection-pulling method that enhances heating uniformity by simultaneously modulating phase and frequency, expanding the locking bandwidth significantly.

Findings

Expanded locking bandwidth from 8 to 18 MHz

Improved heating uniformity in experiments

Validated effectiveness through numerical calculations

Abstract

Conventional microwave heating techniques are limited due to inherent thermal point residency effects and inadequate control over the heating process. A novel method is proposed to enhance microwave heating uniformity using the injection-pulling technique. In this method, the injection-pulling technique is used to achieve simultaneous modulation of both the output phase and frequency of the magnetron, thereby extending the locking bandwidth of the injection-locking technique. The output characteristics of the injection-pulled magnetron were validated through numerical calculations and experiments. Microwave heating experiments were conducted under both a five-cup water load and an absorbent paper load. Compared with conventional injection-locking frequency sweeping, the proposed method not only expands the sweeping bandwidth from 8 to 18 MHz but also further improves heating uniformity, offering more options for magnetron applications in microwave heating.