Low-Noise Dual-Way Magnetron Power-Combining System Using an Asymmetric H-Plane Tee and Closed-Loop Phase Compensation

• Published in: IEEE transactions on microwave theory and techniques Vol. 69; no. 4; pp. 2267 - 2278
• Main Authors: Chen, Xiaojie, Yang, Bo, Shinohara, Naoki, Liu, Changjun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analytical models; Asymmetry; Closed-loop system; Compensation; Couplings; injection locking; Jitter; magnetron (MGT); microwave power combining; Noise; Noise levels; Noise reduction; Numerical prediction; Optimization; Phase control; phase noise; Power generation; Subsystems; Technological innovation; Tuning; Vibration
• DOI: 10.1109/TMTT.2021.3056550
• ISSN: 0018-9480

To meet the increasing power demands of microwave industries and scientific innovations, a dual-way magnetron (MGT) power-combining system based on an asymmetric H-plane tee combined with closed-loop phase compensation (CLPC) was developed and tested. Only one external injection was used, which could lock both frequencies of the two MGTs via the port coupling of the asymmetric H-plane tee. Additionally, phase control was achieved simultaneously in both MGTs. By tuning the external frequency, the frequencies of both MGTs could be shifted to optimize the power-combining efficiency. The optimal combining efficiency was 95.7%. By adjusting the phase of the external injection, the phase for the combining output was adjusted with a control scope in the 0°-360° range. The phase noise level of the combined output was largely inhibited by implementing only one closed-loop phase compensation subsystem. The phase jitter was limited to approximately ±0.5°, and spur suppression ratios of −61.0 dBc/Hz at 10 Hz, −80.9 dBc/Hz at 100 Hz, −91.6 dBc/Hz at 1 kHz, and so on were achieved. Moreover, we deduced the corresponding power-combining theories in the asymmetric H-plane tee and noise reduction using the closed-loop compensation method. The numerical predictions qualitatively agreed with the experimental results. Additionally, this research reveals that the proposed techniques have great potential for future power-combining systems because they provide higher power output and noise reduction.