A High-Gain Antenna Based on Ultrathin Planar-Feed Air-Filled Resonant Cavity

This paper presents the antenna characteristics of the high gain and low-profile planar configuration at 10 GHz. The antenna structure is based on a 3-D air-filled cavity between parallel surfaces consisting of a square patch array and perfect ground conductor. The patch array behaves as a partially reflective surface to interact with a perfect conductor plane in order to control a reflection-phase response. Its property enables a resonant transmission associated with a metamaterial by applying the electromagnetic image theory. The narrow aperture source was embedded into a perfect ground conductor fed by a short-end coplanar waveguide (CPW) as a driven radiator. The patch array and planar CPW-fed aperture are patterned on an μm-thin liquid crystal polymer (LCP) film to form a resonant cavity antenna. The overall thickness of the proposed antenna is ~1.0 mm with respect to ~λ/30. The radiation aperture of ~55×55 mm
²
corresponds to ~1.83×1.83λ
²
for the effective antenna structure. The investigation shows that the effect of a finite-size lateral structure of 4×4 unit cell was observed for enhanced gain and radiation response. That of the proposed cavity antenna results the directive characteristics of 13.7 dBi which is useful for telemetry applications.