Design and Fabrication of 200-GHz Oversized Surface-Wave Oscillator

Annaka, Yuta; Ogura, K.; Rachi, Keiichiro; Hoshi, Y.; Kubo, S.; Shimozuma, Τ.; Kobayashi, S.; Okada, Kohji

doi:10.1109/tps.2020.2998119

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…The 2D corrugation provides the additional benefit of mitigating charge accumulation and RF breakdown. Employing 2D geometry (in place of the 1D corrugation typically favored in conventional surface wave and backward wave oscillators (BWOs) [12][13][14][15][16]) can enhance the spectral purity, output power and electronic efficiency of the device [11]. Diverse, highimpact applications of the pulsed 2D-PSL sources include: communications, environmental sensing, dust cloud monitoring, enhancing nuclear magnetic resonance (NMR) spectroscopy using dynamic nuclear polarization (DNP-NMR), long range imaging, pulsed high-frequency electron paramagnetic resonance (EPR) for biomolecular characterization, non-destructive testing, plasma scattering diagnostics and radar systems [17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Electron Cyclotron Absorption in Powerful Narrow-Band Sub-THz Oscillators Exploiting Volume and Surface Modes

MacLachlan

Robertson

Cross

et al. 2023

IEEE Trans. Electron Devices

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We present the theory, design and numerical modeling of novel, pulsed sub-THz oscillators based on cylindrical, two-dimensional (2D) periodic surface lattice (PSL) interaction cavities. Investigation of the electronic efficiency and power dependence on the magnitude of the magnetic guide field and the electron beam current is investigated. While cyclotron absorption effects have been studied in low order, 1D BWOs, few studies have considered cyclotron absorption in highly overmoded, 2D-PSL oscillators. Here we investigate certain behavior associated with cyclotron absorption in 2D-PSL devices with over 400 modes. This electron cyclotron absorption is shown to be a universal process, independent of frequency and transverse cavity size. Dispersive behavior shows minimal group velocity at the point of interaction and demonstrates similarities with degenerate band edge phenomena. In this work, the fundamental mode selection mechanism relies on the coupling of high-order volume and surface waves. Good agreement between theory and modeling is presented.

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Section: Introductionmentioning

confidence: 99%

The Effects of Electron Cyclotron Absorption in Powerful Narrow-Band Sub-THz Oscillators Exploiting Volume and Surface Modes

MacLachlan

Robertson

Cross

et al. 2023

IEEE Trans. Electron Devices

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“…Spanning the 'THz gap' using vacuum electronic sources, whilst maintaining HP output, poses significant challenges, namely: (i) the avoidance of RF breakdown, (ii) the provision of adequate cooling and (iii) manufacturing limitations [8] associated with the small cavity dimensions. One promising type of slow-wave device where these difficulties can be resolved by making the interaction cavity diameter D several times the free space operating wavelength 𝜆, whilst introducing a cosinusoidal corrugation at the inner wall, is a surface wave oscillator (SWO) [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In contrast to standard sources where 𝐷~𝜆, the interaction cavity of the SWO is oversized and therefore highly overmoded.…”

Section: Introductionmentioning

confidence: 99%

“…The generation of HP radiation is enabled by the excitation of a localized surface field at the inner cavity wall. SWOs based on one-dimensional (1D) periodic structures have been designed at 0.14, 0.319-0.349 THz [16,17] by Wang et al and 0.2 THz by Annaka et al [18]. We present theoretical, analytical and numerical results for a SWO with a complex, two-dimensional periodic surface lattice (2D-PSL) interaction cavity and demonstrate high-order mode selection, achieved by coupling volume and surface fields to form a hybrid cavity eigenmode.…”

Section: Introductionmentioning

confidence: 99%

Efficient, 0.35-THz Overmoded Oscillator Based on a Two-Dimensional Periodic Surface Lattice

MacLachlan

Robertson

Cross

et al. 2022

IEEE Trans. Electron Devices

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We present the theory, design and numerical modeling of a cylindrical, two-dimensional (2D) periodic surface lattice (PSL) intended for use as the interaction region of an electron beam driven, pulsed source. The production of 1.95MW peak, pulsed 0.35THz radiation with an electronic efficiency of 24% is reported. Mode selection in the oversized cavity, where the diameter D is almost 3.5 times larger than the operating wavelength 𝝀, is achieved by coupling volume and surface fields to form a coupled cavity eigenmode.We demonstrate the advantages (including enhanced output power and improved spectral purity) of using a 2D-PSL over a simpler 1D structure. The cylindrical 𝑫 𝝀~𝟑. 𝟓 ⁄ 2D-PSL demonstrates the 'proof-of principle' high-order mode coupling with the potential to increase 𝑫 𝝀 ⁄ to values of 20 or more for the realization of CW 2D-PSL sources or very powerful pulsed sources. The theory is applicable over a broad frequency range.

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Applications of Surface Wave Propagation

Гірка

Thumm

2022

Surface Flute Waves in Plasmas

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Design and Fabrication of 200-GHz Oversized Surface-Wave Oscillator

Cited by 8 publications

References 25 publications

The Effects of Electron Cyclotron Absorption in Powerful Narrow-Band Sub-THz Oscillators Exploiting Volume and Surface Modes

The Effects of Electron Cyclotron Absorption in Powerful Narrow-Band Sub-THz Oscillators Exploiting Volume and Surface Modes

Efficient, 0.35-THz Overmoded Oscillator Based on a Two-Dimensional Periodic Surface Lattice

Applications of Surface Wave Propagation

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