Reflective Antenna Arrays Research Articles

A RECONFIGURABLE METASURFACE IN THE FORM OF A FABRY-PÉROT RESONATOR, INVOLVING SEMI-TRANSPARENT MIRRORS AND A NONLINEAR DIELECTRICINSERT

Subject and Purpose. The paper is aimed at suggesting ways for implementing electromagnetic devices that would involve a nonlinear dielectric inside the structure for concentrating electromagnetic field within it at relatively low intensities of the excitation field. A representative example is offered by a Fabry-Pérot resonator with semi-transparent mirrors and a nonlinear dielectric inside. Methods and Methodology. The paper presents a fundamentally new approach to controlling the frequency response of a metasurface, and a method for protecting electronic modules from high excitation powers. The method is based on the use of nonlinear properties of a Fabry-Pérot "resonator-capacitor" containing a nonlinear dielectric in its volume. Thus, we propose a method for creating spatial filters and antenna protecting fairings capable of active reconfiguration. Results. Analysis of the results has shown that by changing the voltage across the resonator-capacitor plates it is possible to control the degree of electromagnetic field localization in the resonator volume. The frequency response of the metasurface based on the Fabry-Pérot resonator with a nonlinear dielectric inside can be reconfigured by changing the voltage applied to the resonator mirrors. The advantages provided by electrical control of the frequency-selective characteristics include an increased efficiency and possibility of integrating digitally controllable systems into antennas. Conclusions. The use of a Fabry-Pérot "resonator-capacitor"model, with a nonlinear dielectric inside, in the capacity of a reconfigurable metasurface, else as a power limiter in a variety of devices, has sufficient prospects for application in microwave transmitting systems. A special area of application for the reconfigurable Fabry-Pérot resonators is creation of broadband receive antenna systems for direction- finding. In essence, the proposed Fabry-Pérot resonator is a reflective antenna array with an ability to exhibit, conceal or alter its electrodynamic properties according to a certain algorithm. This opens up prospects for its application in "friend-or-foe" recognition systems, reflective beacons, navigation systems, etc.

POSIBILITY OF CREATING A PRINTED SINGLE-LAYER TRANSREFLECTOR WITH INCREASED PHASE EFFICIENCY

A new type of single‑layer transrefleсtor structure based on microstrip reflective antenna array is described. The developed device is a single‑layer printed circuit board on one side of which a system of printed reflectors is located, and on the other is a polarization structure consisting of parallel metal conductors, in contrast to a microstrip reflectarray antenna. The shape and geometrical dimensions of printed reflectors arranged in a rectangular or hexagonal (triangular) pattern are chosen in such a way that they transform a spherical front of an incident vertically polarized electromagnetic wave into a flat front of reflected wave. In the case of irradiation of the developed transreflector with a horizontal polarization wave, the printed structure makes minimal electromagnetic energy loss during its passage. The results of characteristics modeling (including phase curves) of an element of the reflective lattice in the W‑band for different angles of incidence of the wave on the planar structure under study are given. Based on the results obtained, the sizes of the reflective elements of the transreflector, which provide for the correction of the incident wave with the necessary phase discrete, are determined and an electrodynamic model of the transreflector antenna is built. The simulation of the main radiation characteristics of the antenna with the developed single‑layer transreflector was carried out.