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

Abstract

Planar periodic surface lattice (PSL) structures based on thin, subwavelength substrates have been studied experimentally and numerically. Coupled eigenmode resonances composed of partial volume and surface modes are observed for PSLs with lattice periodicities of 1.50 mm and 1.62 mm etched onto thin copper-backed, substrates. We show that the copper backing is essential for mode-selection in a multi-moded structure and demonstrate good agreement between the experimental results and coupled dispersion plots calculated using CST Microwave Studio. For the first time, evidence of a coupled eigenmode in a metadielectric PSL is presented. It is shown that metadielectric PSLs can support coupled resonances over a narrow bandwidth and are relevant to the innovation of tunable filters, absorbers and sources. Concepts discussed in this work are valid across the frequency spectrum from optical to THz and mm-wave frequencies and are fundamental to the innovation of novel mm-wave-THz sources as well as highly efficient solar cells, diagnostic instruments and antennae.

Investigation of dynamic behaviour of circular plates resting on Winkler and Pasternak foundations

“…Solving the simultaneous equation [Eqs. (20) and (21)] to find the unknowns and substitute back to Eq. (17).…”

“…Galerkin of weighted residual handles circular plate vibration problem without any manipulation of governing equation with very precise results compared to experimental with few iterations. Other recent publications reported on vibration are [20][21][22][23][24][25].…”

Excitation and coupling of volume and surface fields on complex electrodynamic surfaces at mm‐wave and THz frequencies

“…Periodic structures, both one-and two-dimensional (1D and 2D), have importance in 'fast-wave' and 'slow-wave' applications, for instance in free-electron lasers where they can be implemented as Bragg reflectors. Historically, periodic structures of coaxial, cylindrical, and planar geometries have been studied [1][2][3][4][5][6][7][8][9]. The current work, which concerns 2D planar and cylindrical periodic surface lattice (PSL) structures, is driven by the desire for highly overmoded high-power 'slow-wave' (Cherenkov) sources of electromagnetic radiation.…”

Highly Overmoded MM-wave Oscillator Experiments

“…Theoretical analysis [4,5,7,8] shows that by careful design of a two dimensional PSL situated on the inner surface of the cylindrical electron beam -wave interaction structure can result in a coupling of surface waves and volume waves in the interaction structure to produce a single frequency powerful output mm-wave. The concept of this coupling process has been experimentally demonstrated [9] using a planar two dimensional periodic lattice. The planar PSL can in principle be conformally mapped into a cylindrical PSL.…”