Extended Interaction Circuit Based on two Beams with Arbitrary Uniformity for High Power Sub-Terahertz Applications

The use of two and multiple beams in extended interaction oscillators (EIOs) provides an efficient solution to significantly increase the power level at millimeter and THz frequency 1 , 2 . One of the most important factors determining stable operation of such oscillators with this solution is to eliminate the negative effect of the non-uniformity of two or more beams on the stable operation of the devices 1 , 2 . To achieve this point, we propose a novel extended interaction circuit based on two beams with arbitrary uniformity for stable, high power sub-THz EIOs. In contrast to conventional EIOs, which are depended on the interaction between the fundamental mode and a single beam in typical ladder-type resonant cavities, the novel circuit with the TM 13 mode mechanism duplicates the electromagnetic characteristics of conventional EI O circuits through establishing three sections of half-wavelength, standing-wave fields across the interaction gaps. Among them, one section distributed across the gaps with coup ling cavities reproduces the conventional TM 11 mode and the rest two sections provide the interaction conditions for two beams with arbitrary uniformity. Simulations results show that the output power of a G-band EIO based on this novel circuit is changed within a small difference in the currents of two beams at a given voltage and then tends to be saturated with a large difference in those of two beams. This demonstrates the EIO has the ability of operating stably even with two extremely non-uniform beams. Thus the novel circuit is promising in generating high power millimeter-wave, and THz wave for many technique applications.