Design and Fabrication of a Dielectric-Supported Symmetric Dual Meander-Line Slow Wave Structure

A novel dielectric-supported symmetric dual meander-line (DS-SDML) slow wave structure (SWS) at Q-band is proposed in this article. Simulation results demonstrate that this symmetric double-layer SWS operates in two fundamental modes, each corresponding to distinct electric field distributions. Among the modes, the even mode has a higher coupling impedance. A stepped ridge waveguide type input/output coupler is designed to achieve even mode and standard waveguide mode conversion, and the results indicate that SWS has excellent transmission characteristics. Particle-in-cell (PIC) simulations are employed to evaluate the performance of the high-frequency circuit. Under the condition of 9300-V voltage, 0.08-A current, and 0.56-W saturated input power, the maximum output power can reach 84.9 W. Furthermore, the phase of the output signal at various frequencies within the desired bandwidth is presented, considering a small signal output gain of 25.2 dB. Over 11% electronic efficiency and 1-dB bandwidth of 10% centered at 39 GHz can be realized with an interaction length of 36.5 mm. Besides, a concise description of the fabrication and assembly method of this DS-SDML SWS is provided to accomplish cold tests while maintaining small deformations. After modifying the SWS model, the range of experimental and simulation results is basically the same, the insertion loss observed is explained in detail, and subsequent solutions are given.