Double-Staggered Grating Waveguide Slow Wave Structure for Terahertz Traveling Wave Tube.

Area of Science:

• Physics
• Electrical Engineering
• Microwave Engineering

Background:

• Traveling Wave Tubes (TWTs) are essential for high-frequency signal amplification.
• Designing efficient slow wave structures (SWS) for millimeter-wave frequencies presents significant challenges.
• Optimizing impedance matching between components is critical for device performance.

Purpose of the Study:

• To design and simulate a novel double-staggered grating waveguide slow wave structure (DSGW-SWS) for a 340 GHz traveling wave tube (TWT).
• To develop input and output couplers for electromagnetic (EM) signal isolation.
• To enhance circuit-coupler matching through height tapering in transition sections.

Main Methods:

• Design of a DSGW-SWS optimized for 340 GHz operation.
• Development of specialized input and output couplers for EM signal isolation.
• Particle-in-cell (PIC) simulations using an ideal sheet electron beam (SEB) source with a 50% filling factor.

Main Results:

• Achieved a wide reflection coefficient bandwidth from 326 GHz to 364 GHz below -15 dB.
• Simulated signal amplification from an average input power of 0.19 W to 17.4 W.
• Obtained a significant gain of 19.55 dB for the 340 GHz signal.

Conclusions:

• The designed DSGW-SWS demonstrates effective performance for high-frequency TWT applications.
• The integrated design of SWS, couplers, and transition sections ensures efficient signal transmission and amplification.
• PIC simulations validate the potential of this structure for achieving high gain at 340 GHz.