The development of broadband millimeter-wave and terahertz gyro-TWA

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He, W. and Zhang, L. and Donaldson, C. R. and Yin, H. and Ronald, K. and Cross, A. W. and Phelps, A. D. R. (2020) The development of broadband millimeter-wave and terahertz gyro-TWA. Terahertz Science & Technology, 13 (3). pp. 90-110. ISSN 1941-7411

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Abstract

The gyrotron travelling wave tube amplifiers (gyro-TWAs) presented in this paper can operate with high efficiency (30%), huge powers and wide bandwidths at high frequencies that no other amplifier can provide. In principle, this is a technology that can be scaled to >1 THz and operate with 20% bandwidths. Resonant coupling of two dispersive waveguide modes in a helically corrugated interaction region (HCIR) can give rise to a non-dispersive eigenwave over a wide frequency band. The synchronism between the ideal wave and an electron cyclotron mode, either fundamental or harmonic, of a large orbit electron beam contributes to the broadband amplification. An electron beam of 55 keV, 1.5 A with a velocity pitch angle of ~1 generated by a thermionic cusp gun is used in our 100 GHz gyro-TWA experiment, which achieves an unsaturated output power of 3.4 kW and gain of 36–38 dB. The design and experimental results of the many components making the gyro-TWA will be presented individually and then the whole system will be introduced. The amplification of a swept signal by the W-band gyro-TWA is demonstrated showing its capabilities in the field of telecommunications. Furthermore, the design studies of a cusp electron gun in the triode configuration and the realization of a 3-fold HCIR operating at 372 GHz will also be displayed.

ORCID iDs

He, W., Zhang, L. ORCID logoORCID: https://orcid.org/0000-0002-6317-0395, Donaldson, C. R. ORCID logoORCID: https://orcid.org/0000-0001-6627-2461, Yin, H. ORCID logoORCID: https://orcid.org/0000-0002-6635-9759, Ronald, K. ORCID logoORCID: https://orcid.org/0000-0002-8585-0746, Cross, A. W. ORCID logoORCID: https://orcid.org/0000-0001-7672-1283 and Phelps, A. D. R. ORCID logoORCID: https://orcid.org/0000-0002-1100-1012;
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