Исследование свойств и возможности выделения обратных волн в неоднородных псевдопериодических слоистых средах
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.