Broadband and high-power terahertz radiation source based on extended interaction klystron

Area of Science:

• Physics
• Electrical Engineering
• Applied Electromagnetics

Background:

• Terahertz (THz) applications demand high-performance radiation sources with high output power and broad bandwidth.
• Extended Interaction Klystrons (EIKs) show potential for generating hundreds of watts in the THz band.

Purpose of the Study:

• To improve the bandwidth and output power of THz EIKs.
• To investigate the impact of multiple gap cavities and unequal-width slots on EIK performance.

Main Methods:

• Design and analysis of a THz EIK featuring multiple gap cavities with unequal-width slots.
• Particle-in-cell (PIC) simulations to analyze electromagnetic field distribution and beam-wave interaction.
• Implementation of stagger-tuning and dynamic-tuning techniques.

Main Results:

• The unequal-width slots structure enhances frequency separation and effective characteristic impedance.
• Initial G-band EIK design achieved a bandwidth of 550 MHz.
• Stagger-tuning extended the bandwidth to 1-1.5 GHz.
• Dynamic-tuning further broadened the bandwidth to over 2 GHz, with 560 W output power, 11.3% efficiency, and 47.5 dB gain.

Conclusions:

• Multiple gap cavities with unequal-width slots are crucial for improving THz EIK bandwidth.
• Stagger-tuning and dynamic-tuning are effective strategies for bandwidth enhancement.
• The proposed EIK design offers a promising solution for high-power, broad-bandwidth THz radiation sources.