Photonic Crystal-Coupler for Sheet Beam THz Vacuum Electron Tubes

Abstract

Fig. 1. Schematic diagram of a typical coupler for a sheet beam in a CRW. Abstract-Photonic Crystal (PhC) technology was recently proposed as a compact and effective solution to improve the performance and ease the fabrication of terahertz vacuum electron devices. In particular, the introduction of defects in a bidimensional, all metallic PhC provides very effective transmission of the useful signal in a compact input/output coupler where a novel tunnel for sheet-beam injection/collection is realized. Simulation results are here experimentally validated via measurements on a Ku-band scaled model of the PhC-coupler which confirm the validity of the concept.

Mode coupling in periodic surface lattice and metamaterial structures for mm-wave and THz applications

“…Efficient, high power millimetre and terahertz radiation sources are highly sought after for their diverse and farreaching applications in optics, imaging [1][2][3] and security [4], communications [4][5][6] medical technology, particle acceleration [7,8] spectroscopy [9][10][11] and scientific research [12][13][14][15]. Traditionally, sources were scaled according to their output frequency, requiring smaller interaction regions and consequently diminished power capabilities, at shorter wavelengths.…”

Millimeter-wave periodic surface lattices for mode control in vacuum electronic sources

“…To advance the performance parameters and extend the frequency range of vacuum electronic devices, electromagnetic structures that can enhance and control the mode selection process in the beam wave interaction region are being investigated. Various structures and materials such as diffractive surfaces [1], metamaterials [2], photonic structures [3], metadielectrics and periodic surface lattices [4] are being studied in different regimes of operation. The use of such diverse structures enables the wave dispersion to be engineered within its own discrete parameter space with often shared theoretical principles, and similar numerical modelling methods being used.…”

Application of planar helix slow-wave structure in backward-wave oscillators

“…Side walls with photonic crystals can provide more spacing around the central corrugations and thus reduce the difficulty in vacuum pumping. Photonic crystals have also been used for designing couplers with minimum loss in BWOs [22].…”