Design of a Ka-band gyro-TWT for radar applications

Abstract

Abstract-The design of a Ka-band gyrotron traveling wave tube (TWT) amplifier capable of operating over a wide range of peak powers and bandwidths is presented. The amplifier operates in the TEn mode at the fundamental cyclotron harmonic. Instantaneous bandwidths in the range of 2.5 to 3.9 GHz (at 1 dB below saturation) with corresponding peak powers between 92.2 and 57.9 kW can be achieved by simply adjusting the mod-anode voltage of the electron gun. The corresponding gains range from 57.1 to 36.0 dB. The design performance is obtained with a high quality, 6 A, 70 kV electron beam generated with a double-anode magnetron injection gun. This wide range performance capability in the design is achieved via the use of the distributed loss approach in the interacting circuit, which also guarantees zero-drive stability. A diffractive loading scheme is employed in the lossy section of the circuit to ensure high average power operation of the amplifier.

Stability analysis of a coaxial-waveguide gyrotron traveling-wave amplifier

“…11-17. Most of the gyro-TWTs developed in the past have used either cylindrical or rectangular waveguides as interaction structures. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Mode competition problems in a high-power gyrotron oscillator can be reduced using coaxial structures, [18][19][20][21][22] so several recent studies have examined the possibilities of using a coaxial waveguide as the interaction structure of a gyro-TWT. In Ref.…”

Design and Measurement of a Novel Overmoded TE01 Mode Converter for a Rectangular Gyro-TWT

“…The gyro-TWT as a millimeter-wave source has the characteristics of high power, high frequency, and wide bandwidth. It has promising prospects in high-resolution imaging radar, electronic countermeasures, and subsequent generations of communication systems beyond 5G/6G [1][2][3][4][5].…”

Nonlinear full-wave-interaction analysis of a gyrotron-traveling-wave-tube amplifier based on a lossy dielectric-lined circuit

“…11 With the efforts of Chu and his co-workers, 2 the cornerstone experiment based on the distributed loss technique carried out at National Tsing Hua University, Taiwan achieved 93 kW peak power, 26.5% efficiency, 8.6% bandwidth, and a surprising 70 dB gain with zero-drive stability. This induced the latest upsurge in gyro-TWT research actives, and a series of novel and highaverage power compatible interaction circuits with distributed loss ability are proposed, including the lossy dielectricloaded and metal ring-intercepted circuit, 5,12 the radial-sliced radiation circuit, 6,13,8 and the partial side wall-opened confocal waveguide. 14 The delightful results achieved in these experiments have proved that the distributed loss technique is a general applicable method to stabilize the spurious oscillations in the circuit, and continuously promoted the gyroTWTs developing toward practical applications.…”

“…14 The delightful results achieved in these experiments have proved that the distributed loss technique is a general applicable method to stabilize the spurious oscillations in the circuit, and continuously promoted the gyroTWTs developing toward practical applications. [1][2][3][5][6][7][8][11][12][13][14] The dielectric-loaded waveguide has been widely applied in gyrotron devices. [15][16][17][18][19] It is normally adopted as a drifting tube in a gyrotron or a gyroklystron, and functions as an important component to absorb the spurious oscillation power and strengthens the system stability.…”