A simple method for estimating the quality factor of cylindrical re-entrant cavity of Klystrons

ABSTRACT

A simple method for estimation of the unloaded quality factor of single and double re-entrant cylindrical cavities was developed based on Wheeler’s incremental inductance rule. The proposed approach was benchmarked for a Ka-band re-entrant cavity against 3D electromagnetic simulation using CST Studio and also with measurements. The analysis is general and unlike the approach of Fujisawa, it could be extended to analyze the re-entrant cavity comprising dissimilar materials. The effect of surface roughness on the quality factor of the cavity also could be estimated using the present analysis.

KEYWORDS:

• Conductive loss
• cylindrical re-entrant cavity
• Klystron
• quality factor
• surface finish
• Wheeler’s incremental inductance rule

Acknowledgement

Authors would like to thank Director, MTRDC to give permission to carry out this study and publish the same and to BM Fazalunnissa for her support in making the cavity assembly and carrying out the measurements. Authors are also thankful to the reviewers for the many valuable suggestions to improve the work.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Ashok Bansiwal http://orcid.org/0000-0002-2226-9364

K. J. Vinoy http://orcid.org/0000-0003-0677-2901

Subrata Kumar Datta http://orcid.org/0000-0001-6618-7232

Additional information

Notes on contributors

Ashok Bansiwal

Ashok Bansiwal received his B.E. degree in Electronics Engineering from the Engineering College, Kota, India, in 1999 and M.Tech. degree in Electronics and Communication with specialization in Microwaves from the Indian Institute of Technology, Roorkee, India, in 2001. He has been working as a scientist at the Microwave Tube Research and Development Centre (MTRDC), DRDO, India, since 2001. Presently, he is perusing Ph.D. from the Indian Institute of Science (IISc), Bangalore, India, and his areas of research are circuit analysis of cavity interaction structure, coupling circuits and large signal analysis of Klystrons.

Sushil Raina

Sushil Raina received his B.Sc.(H) Physics, M.Sc. (Physics) and M.Tech. (Microwave electronics) from the University of Delhi, India, in 1989, 1991 and 1993, respectively. He joined the Microwave Tube Research and Development Centre (MTRDC), DRDO, India, in 1993, and since then he has been working toward the research and development of various microwave tubes such as TWTs, magnetrons and klystrons.

K. J. Vinoy

K.J. Vinoy received the bachelor's degree from the University of Kerala, India, master's degree from the Cochin University of Science and Technology, India, and Ph.D. degree from the Pennsylvania State University, USA, in 1990, 1993, and 2002, respectively. He is currently working as a professor in the Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore, India. He was a research assistant at the Center for the Engineering of Electronic and Acoustic Materials and Devices (CEEAMD) at the Pennsylvania State University from 1999 to 2003.

Subrata Kumar Datta

Subrata Kumar Datta received the B.E. degree in Electronics and Telecommunications Engineering from Bengal Engineering College, Calcutta University, Kolkata, India, in 1989 and the M.Tech and Ph.D. degrees in Microwave Engineering from the Institute of Technology, Banaras Hindu University, Varanasi, India, in 1991 and 1999, respectively. Since 1991, he has been a Scientist with the Microwave Tube Research and Development Centre, Defence Research and Development Organisation, Bengaluru, India.