Fast H-Waves in Double Comb Infinite Arrays

Abstract

Abstract-A rigorous approach to study the fast H-waves which propagate across an infinite double comb array (IDCA) is proposed. It is based on the Floquet theorem combined with the advanced moment method (Galerkin) scheme in which the basis explicitly satisfies the edge conditions at the rectangular wedge. An exhaustive analysis of the regular and singular modes of the IDCA is made. Normalized critical wave numbers and modal fields are investigated in terms of geometrical parameters. Coupling effects between different IDCA modes are found. For the singular modes a new analytical formula for the critical normalized wave numbers is obtained.

Diffraction Radiation Oscillator With Frequency Tuning on Mutual Coupled Modes in an Open Resonant System

“…where c is the speed of light in vacuum, λ cr ≈ 2a -the critical wavelength of fast H 10 -wave that propagates in the double comb along OZ [12]. The change of the shift s between the mirrors symmetry planes in this ORS allowed to control the value of mutual coupling between the even T EM 002 -mode and odd T EM 101 -mode.…”

“…At the shift between mirrors symmetry planes s = 2.5 mm, the zone of mutual coupled modes existence extended. This contributed to significant reduction of starting current at DRO tuning down the frequency on the lower branch of mutual coupled modes at f cr < f < f MCP , where f cr ≈ c/2a =26.88 GHz -cutoff frequency of the H 10 wave in a double comb array [12]. At DRO tuning on the upper branch of the mutual coupled modes T EM 002 ↔ T EM 101 , the calculated value of starting current at f > f MCP was only 1.5-2 times larger than the starting current of DRO on the lower branch of mutual coupled modes.…”