Dual-Mode Reltron

We propose exciting two modes concurrently inside a reltron's modulating cavity to increase the microwave power generated. From the harmonic components of the beam, we demonstrate that a multiharmonic beam has a higher peak and steeper gradient compared to a single-harmonic beam. We design a modulating cavity and an extraction cavity that are able to excite the TM 010 mode (2.395 GHz) and TM 110 (3.579 GHz) modes separately or concurrently. Particle-in-cell simulations show that the total microwave generated for the single TM 010 mode is 81 MW (efficiency of 23%) and the single TM 110 mode is 40.5 MW (efficiency of 17%). The total microwave power generated by exciting both modes is 128 MW (efficiency of 35%) and is higher than the power generated by individual modes.