Abstract: Microstrip traveling wave tubes (TWTs) have garnered significant attention due to their potential applications in communication, defense, and industrial systems. This paper presents a compact W-band dual-channel TWT, utilizing a U-shaped microstrip meander-line slow-wave structure (SWS). High-frequency characteristics are analyzed through simulation and cold tests. The results demonstrate that adjusting structural parameters effectively optimizes the S-parameters. Particle-in-cell (PIC) simulations with an 18.8 kV, 0.1 A electron beam predict an output power of 18 W with a gain of 14 dB. Experimental measurements of S-parameters are conducted using three substrate materials: Rogers 5880, quartz, and diamond. The quartz substrate exhibits the closest agreement with simulation results. The results advance the development of the microstrip-based TWTs for high-data-rate communication systems.