Abstract- Criteria for Determining Maximum Theoretical Oscillating Frequency of Extended Interaction Oscillators for Terahertz Applications

 Hooman Bahman Soltani, Habibollah Abiri

http://ieeexplore.ieee.org/document/8307245/

Extended interaction oscillators (EIOs) are high-frequency vacuum-electronic sources, capable to generate millimeter-wave to terahertz (THz) radiations. They are considered to be potential sources of high-power submillimeter wavelengths. Different slow-wave structures and beam geometries are used for EIOs. This paper presents a quantitative figure of merit, the critical unloaded oscillating frequency ( fcr ) for any specific geometry of EIO. This figure is calculated and tested for 2π standing-wave modes (a common mode for EIOs) of two different slow-wave structures (SWSs), one double-ridge SWS driven by a sheet electron beam and one ring-loaded waveguide driven by a cylindrical beam. The calculated fcrsare compared with particle-in-cell (PIC) results, showing an acceptable agreement. The derived fcr is calculated three to four orders of magnitude faster than the PIC solver. Generality of the method, its clear physical interpretation and computational rapidity, makes it a convenient approach to evaluate the high-frequency behavior of any specified EIO geometry. This allows to investigate the changes in geometry to attain higher frequencies at THz spectrum.

Abstract-Experimental demonstration of a terahertz extended interaction oscillator driven by a pseudospark-sourced sheet electron beam

G. X. Shu, L. Zhang,   H. Yin, J. P. Zhao,   A. D. R. Phelps, A. W. Cross, G. Liu, Y. Luo, Z. F. Qian,  W. He

http://aip.scitation.org/doi/abs/10.1063/1.5011102

We have recently proposed to combine the advantages of a pseudospark-sourced sheet electron beam (PS-SEB) with a planar slow wave structure to generate high power terahertz radiation. To verify this idea, experimental investigation of an extended interaction oscillator based on the PS-SEB has been conducted and presented. A PS-SEB of approximately 1.0 mm × 0.17 mm in size with 21.5 A peak current (1.26 × 104 A/cm2 beam current density) and 34.5 kV peak voltage was measured after propagating a distance of 10-mm without the need of an external focusing magnetic field. A radiation pulse of ∼35 ns in duration and an output power of over 10 W at a frequency of ∼0.2 THz were measured.