multi-band high impedance surfaces using progressively magnified ebg structures

Electromagnetic band gap (ebg) structures are widely used in antenna engineering, low-rcs surfaces and electronic devices. in this paper, the effect of magnifying dimensions of an ebg structure on its bandwidth (bandgap) is explored and multi-band high impedance surfaces (his) built by the magnified ebg structures are presented. the proposed structures are applicable to uwb antennas for improving radiation performance, as well as designing low-rcs surfaces. the main idea is to achieve a multi-band his by combining single-band ebg structures. the advantage of this combination is achieving multi-band surfaces, while it results in multi-band surfaces with narrower bandgaps compared with the bandgaps of unit cells which construct the combined surfaces. the disadvantage is due to the parasitic effects of combining ebg structures.