To Use or Not to Use the Effective Medium Approach for Designing Performance-Enhanced Small Antennas - That is the Question

Performance enhancement of small conformal antennas, e.g., microstrip patch antennas (MPA´s) is often accomplished by adding a superstrate or a substrate, comprising of artificial dielectrics that are also referred to as metamaterials, especially when the effective parameters differ substantially from those of the constituent media. These embellishments to the MPA are designed to increase its effective aperture area, broaden its impedance and pattern bandwidths, improve its side or back lobes, to name just a few. Typically, these metamaterial (or EBG) superstrates, as well as substrates, are designed to have DNG characteristics.