L-band dual-frequency recirculating planar magnetron

Dual-frequency oscillators have been used in many technical disciplines on account of the phase correlation between two output signals or the feasibility of producing beat wave effect. The mechanism to generate two different-frequency microwave outputs from one magnetron was discussed and simulated. Strapping technique and phase velocity modulation were adopted to generate random frequency ratio and adequate output power. The relationship between phase velocity difference and total output power was investigated and the proper variation range of phase velocity difference was discussed. The conclusion above will accelerate the design flow of dual-frequency magnetron in various frequency demand. A method of optimal E/B distribution was also applied to reduce electron recirculating loss and obtained a notable power enhancement. To fulfill the demand of producing two microwave outputs with a desirable 3:4 frequency ratio in L-band, a conventional vacuum electronic device called Dual-Frequency Recirculating Planar Magnetron (DFRPM) was modeled. There was a significant difference between planar magnetron and cylindrical magnetron, one large shared planar cathode provided better thermal stability and separated the cavity into two slow-wave structures (SWSs), consequently, each SWS arose an oscillation at their own operating frequency. The primary frequencies of two output signals were at 1.30 GHz/1.70 GHz and overcame the frequency ratio limitation happened in other design scheme.