Design of a wide-band, in-phase, highly reflecting surface for application in a low-profile EBG-resonator antenna

The height of an EBG-resonator antenna is reduced from half-wavelength to quarter wavelength by employing a highly-reflecting surface (HRS) with in-phase reflection characteristics as the superstrate. A HRS, which has in-phase reflection at 11.8 GHz, is presented. Over a 34% bandwidth, its reflection phase is between -90deg and 90deg, and its reflection magnitude is between -1.5 dB and -0.2 dB. A lambda₀/4 tall, 42times42 mm² EBG-resonator antenna, designed with this HRS surface as the superstrate, is expected to have 12 dB gain and 14.5 dB directivity with 6.8% gain bandwidth.