ANALYSIS AND DESIGN OF 2.5D AND 3D STRUCTURES OF FREQUENCY SELECTIVE SURFACES FOR APPLICATIONS IN MODERN WIRELESS COMMUNICATION SYSTEMS
Frequency Selective Surfaces; Fractal; miniaturization.
This work presents a study on Selective Frequency Surfaces (FSS) 2,5 D and 3D, for applications in modern wireless systems. Initially, 2.5D, patch-like structures are analyzed. The simple FSS are formed by elements in square and spiral turns based on the Minkowski fractal. The use of the fractal curve resulted in a miniaturization of the circuit, the appearance of a new transmission band and a decrease in bandwidth. The 2,5D FSS are formed from the simple structures that, for the formation of their elements, the coils were sectioned in eight parts, where four were printed on the upper face of the dielectric, four on the underside of the dielectric and were connected with cylindrical jumpers of 0.5 mm in diameter. The 2.5D surfaces provided miniaturization of the circuit without the appearance of new transmission bands and without decreasing the relative bandwidth. All HSS were stable with respect to the angle of incidence of the plane wave on the surface of the circuit. The simulated numerical results for the projected prototypes were obtained by Ansoft HFSS software. The prototypes were constructed and the experimental measurements of the transmission coefficients were performed, the values obtained were compared and discussed with the results of the simulations, which showed good agreement.