Asian Journal of Physics Vol 32, Nos 9 – 12 (2023) 659-669

RF behavior of a second harmonic photonic band gap cavity gyrotron oscillator

Ashutosh Singh1, Sandeep Kumar Prasad1, Sunil Kumar Mishra1, Rajnikant Ratnakar2, Anshu Arya2, and Pradip K Jain3
1Department of Physics, Mahesh Prasad Sinha Science College,
Babasaheb Bhimrao Ambedkar Bihar University, Muzaffarpur-843 146, India
2University Department of Physics, Babasaheb Bhimrao Ambedkar Bihar University, Muzaffarpur–842 001, India
3Department of Electronics and Communication Engineering, National Institute of Technology, Patna-800 006, India
Dedicated to Prof B N Basu

The beam-wave interaction behavior of a 35GHz second harmonic photonic band gap cavity (PBGC) gyrotron oscillator is presented operating in a higher order TE3,4,1 mode of operation . The PBGC is used as an interaction structure instead of the conventional tapered cylindrical cavity due to its promising feature of mode selectivity. The second harmonic operation has been chosen to reduce the large magnetic field requirement in the case of high-frequency operation. The RF behavior of the PBGC cavity is observed using multimode theory and the results are validated using a commercially available PIC code. The multimode theory provides the performance of a gyrotron in the presence of all competing modes. The momentum and phase of the electrons are studied in order to analyze the energy transfer mechanism to the RF wave. Around 80 kW of stable output power is achieved in TE3,4,1 mode with ~13% efficiency. The RF output powers obtained from theory and PIC simulation are compared and found in agreement within ~13% difference. The presence of competing modes in PBGC has been considerably reduced and single-mode operation has been achieved. © Anita Publications. All rights reserved.
Keywords: Beam-wave interaction, Photonic band gap, Gyrotron oscillator, Multimode theory, PIC simulation.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
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