Experimental Results on the Harmonic Recirculating Planar Magnetron with All Cavity Extraction*

Harmonic-frequency locking was originally observed on the Multi-Frequency Recirculating Planar Magnetron (MFRPM) [1], which is a high power microwave source that can generate multi-MW power levels at two frequencies simultaneously. To understand harmonic-frequency locking, the Harmonic Recirculating Planar Magnetron (HRPM) has been designed with oscillators at L-Band and S-Band (LBO and SBO, respectively). In the harmonic locked state, the SBO frequency locks to the harmonic of the LBO's frequency. Power is extracted from the SBO using coaxial-all-cavity-extraction [2]. Under certain operating parameters, the SBO has been observed to generate 9.3 $+$/- 1.4 MW when driven by MELBA-C, which applies -300 kV and 1-5 kA for 0.3-1.0 $\mu $s. The completed design, relevant simulations, and experimental results will be presented. [1] Greening et al, ``Harmonic Frequency Locking in the Multi-Frequency Recirculating Planar Magnetron'', IEEE T-ED, vol. 65, 2347, (2018). [2] Franzi et al, ``Coaxial All Cavity Extraction in the Recirculating Planar Magnetron,'' IEEE International Vacuum Electronics Conference, 2014.