Study of the properties and the possibility of allocation of backward waves in inhomogeneous pseudoperiodic-layered media
I. S. Omelchuk, V. A. Solntsev
Moscow Institute of Electronics and Mathematics of
National Research University "Higher
School of Economics"
The paper is
received on September 7, 2015
Abstract.
Periodical electrodynamic structures are widely used to create powerful
electronic devices, microwave filters, antennas. A wider class of heterogeneous
media and slow-wave systems (SWS) is a pseudoperiodic structure proposed for
the selection of waves, including the suppression or amplification of backward
waves. These are, for example, synchronous helix (Solntsev Spiral-SS),
including as a special case of a logarithmic spiral, with the suppression of
pseudoperiodic waveguides parasitic backward waves. The principle of
constructing pseudoperiodic-layered media is similar to the principle of
creating pseudoperiodic waveguides and based on a consistent change in the
thickness of the media’s layers along with the change of electric permittivity
and magnetic permittivity, determining the phase shift of the electromagnetic
field on the layer. According to this principle, the distribution pitch of the
layers and the phase of the field along the structure are selected so as to
maintain the phase velocity and amplitude of the selected spatial harmonics of
the field the same as in the original periodic layered media and the amplitude
of the other spatial harmonics decrease; selection takes spatial harmonics
(spatial selection). In the pseudoperiodic-layered media expected to get a
selection of backward spatial harmonics, which is the production of media with
a backward wave having the opposite direction of propagation phase and energy
flow. Investigation of the properties of electromagnetic waves in
pseudoperiodic-layered media and slow-wave systems opens the possibility of
creating on this basis new microwave devices. Media with a backward wave in recent
years attracted the attention of many researchers, because they have new
unusual laws of reflection and refraction and allow to obtain focus over beams
in the microwave and optical ranges. The well-known works are
"metamedia" based on the use of periodic electrodynamic structures
(photonic or electromagnetic crystals). This paper presents a method and a
program for calculating the properties of electromagnetic waves in a
pseudoperiodic-layered media. Also some possibilities of allocation of backward
waves in an environment that determine the properties of propagation of
electromagnetic waves are shown.
Keywords:
microwave, layered media, slow-wave systems, backward waves, selection.