A novel Ka-band coaxial transit time oscillator with internal extraction

Area of Science:

• Physics
• Electrical Engineering
• Microwave Engineering

Background:

• High power microwave sources are crucial for various applications.
• Extending the operating frequency of these sources to higher bands like Ka-band is an ongoing challenge.
• Traditional designs often face issues with mode competition and extraction efficiency.

Purpose of the Study:

• To propose and investigate a Ka-band coaxial transit time oscillator (TTO) with internal extraction.
• To achieve high output power and efficiency at higher microwave frequencies.
• To suppress asymmetric mode competition for improved device performance.

Main Methods:

• Utilized particle-in-cell (PIC) simulations to model the TTO.
• Investigated device performance under specific operating conditions (voltage, current, magnetic field).
• Conducted preliminary experiments to validate simulation findings and assess mode competition suppression.

Main Results:

• Achieved an output power of 0.75 GW at a frequency of 31.4 GHz.
• Obtained a high efficiency of 42% with a saturation time of approximately 25 ns.
• Demonstrated suppression of asymmetric mode competition in preliminary experiments.

Conclusions:

• The proposed Ka-band coaxial TTO with internal extraction is a promising high power microwave source.
• Internal extraction effectively reduces the over-mode ratio, suppressing asymmetric mode competition.
• This design advances the capability of high power microwave sources to operate at higher frequencies.