Experiments and Simulations of the Recirculating Planar Crossed-Field Amplifier*

The Recirculating Planar Crossed-Field Amplifier (RPCFA) is a high-power microwave amplifier that has demonstrated amplification exceeding 13 dB and 2 MW of output power. The design is derived from the Recirculating Planar Magnetron [1] which has been a topic of research at the University of Michigan. The RPCFA was designed in simulation using two distinct codes, finite element frequency domain code ANSYS HFSS, and the particle-in-cell code MAGIC. Simulation showed up to 13.5 dB of gain with an output power of 29 MW, zero-drive stability, and a bandwidth of 10%, typical for commercial CFAs. An RPCFA prototype has been fabricated to verify the results of simulation. Greater than 10 dB of amplification is observed in a continuous band from 2.63 to 3.05 GHz for a bandwidth of 15.0%. Zero-drive stability has been confirmed experimentally. Significant (σ = 1.6 dB) shot to shot variation in gain is observed in experiment. Several sources of this inconsistency are considered. Future experiments will attempt to improve reproducibility and measure amplification at MW level RF drive.[1] R.M. Gilgenbach, Y.Y. Lau, D.M. French, B.W. Hoff, J. Luginsland, and M. Franzi, “Crossed field device,” U.S. Patent US 8 841 867B2, Sep. 23, 2014.