Multiband FSS with Fractal Characteristic Based on Jerusalem Cross Geometry

H V H Silva Filho,E M F De Oliveira,A Gomes Neto,M R T De Oliveira,M T De Melo,T R De Sousa,C P N Silva

doi:10.1590/2179-10742017v16i4984

Abstract

This paper proposes a new device with modifications on the Jerusalem Cross (JC) geometry to provide a multiband Frequency Selective Surface (FSS). Fractal iterations are created by introducing concentric self-similar JC copies in the original unit cell. This modification results in new dipoles at the structure which allows for the appearance of new bands proportional to these diploles' lengths, while maintaining total unit cell size. Four iterations of the JC FSS are studied in this paper. Simulation results for the insertion loss (S 21 ), surface current distribution and measurement results are presented.

Highlights

Interest in the potential application of fractal geometries has increased
This paper proposes the use of fractal characteristics to design a set of four orientation insensitive (OI) multi-band Frequency Selective Surfaces (FSSs)
This paper investigates the behavior of a modification in the Jerusalem Cross FSS (JC-FSS) [1113]

Summary

INTRODUCTION

Interest in the potential application of fractal geometries has increased. Some fractal shapes are highly convoluted geometries, giving the possibility to embed resonant elements into small areas. When an incident electromagnetic wave encounters a FSS, resonance effects can occur on the grid elements in a given frequency band, depending on the elements’ geometry and periodicity, and the properties of the dielectric substrate [5]. This paper investigates the behavior of a modification in the Jerusalem Cross FSS (JC-FSS) [1113] This modification consists in replicating the JC geometry in different scales to provide a multiband structure without changing the area occupied by the primary structure, hereby called Modified Jerusalem Cross Frequency Selective Surface (MJC-FSS). These modifications present auto-similarity fractal characteristics where each fractal level consists in adding a rescaled JC geometry. The simulation results for insertion loss (S21) and surface currents distribution were obtained using CST Microwave Studio software 2016®

JERUSALEM CROSS FSS

RESULTS AND DISCUSSION

Measurements for incident wave angle sensitivity test

Current Distribution

CONCLUSION