Miniature Antenna Using Printed Coupled Lines Emulating Degenerate Band Edge Crystals

A miniature printed antenna design that exploits higher-order dispersion behavior in degenerate band edge (DBE) crystals is proposed. First, the unit cell of a DBE crystal is emulated using a simple combination of uncoupled and coupled microstrip (MS) line sections printed on a low loss dielectric substrate. Subsequently, a resonant antenna is formed by cascading two such MS-DBE unit cells in a circularly periodic fashion. The first part of the paper is devoted to the antenna/array design and characterization using a low contrast dielectric substrate (Rogers Duroid, isin_r = 2.2). Next, fabrication and design verification using a high dielectric constant substrate (alumina: Al₂O₃, isin_r = 9.6) is given. The manufactured antenna was measured to have a broadside gain of 4.5 dB at 1.48 GHz with 3.0% bandwidth. For this gain and bandwidth, we demonstrate that the proposed MS-DBE antenna has a lambda₀/9 times lambda₀/9 footprint and is among the smallest in the literature.