Experimental Study of Realizing a Low-Noise Injection-Locked Magnetron Based on a Switch-Mode Power Supply

Injection-locked magnetrons (ILMGT) are potential candidates in various industrial applications, for example, wireless power transmission. Generally, the output phase and amplitude stability of an ILMGT are influenced by the voltage or current ripple of its power supply. Thus, a high-performance ILMGT cannot exist without an excellent power supply. Switch-mode power supply (SMPS) has the advantages of being compact, high-efficiency, and high-controllability, but it also has a high-ripple and noisy output. Our study is to depress anode voltage ripple without excessive volume and complexity increase. A novel ripple reduction method is proposed. The peak-to-peak value of the SMPS’s voltage ripple is reduced from 282 V to 29 V. The output phase jitter of the ILMGT is suppressed from 49° to 0.7° when the injection ratio is 0.13. Besides, the 100-Hz noise is almost completely eliminated without any 100-Hz LC filter. This study provides a reference to establish a compact and low-noise ILMGT system based on commercial SMPSs.