Design of Large-Band Highly Directive Antenna in the Millimeter Waves Range at 80 GHz

This paper presents the design of a broadband highly directive antenna developed for point-to-point communications systems in the millimeter-wave band around 80 GHz (E-band domain). High directivity (about 38 dBi) and very few degrees opening angle are required for this application from 81 to 86 GHz. A Fabry-Perot cavity excited by primary source array (NxN standard WR12 waveguides) is coupled to a metamaterial dual-layer partially reflective surfaces (PRS). The designed PRS is used as a transmitting window and optimized in order to achieve a positive gradient phase (PGP) of the reflection coefficient over the entire considered bandwidth (≈5GHz). The goal is to compensate, even partially, the delay due to multiple interference paths in order to maintain the cavity resonance condition. The dimensions of the planar antenna are 100x100 mm
²
. The full wave numerical results show a positive linear gradient phase (PGP) of about 13 ° and a quasi-unchanged directivity with a peak value of about 38 dBi. The designed antenna is highly directive, ultra-compact and low profile with good performances over the entire E-band 81-86 GHz.