Highly Efficient, Wideband Microstrip Patch Antenna With Recessed Ground at 60 GHz

The effects of finite air-filled recessed ground on the reflection and radiation characteristics of a microstrip patch antenna at 60 GHz are investigated. The recessed ground patch antenna is analyzed using a 2-D capacitance model to understand the effect of the dimensions of the recessed ground plane on the effective dielectric constant. A detailed parametric study of the dimensions of the recessed ground plane is carried out to optimize the performance of the patch antenna at 60 GHz. Prototypes of a conventional and optimized recessed ground patch antenna at 60 GHz are fabricated on alumina ceramic substrate of height 0.127 mm with ε
_r
= 9.8. The measured results indicate that with the recessed ground plane, an enhancement in -10 dB impedance bandwidth by 9.48% (58.2-65 GHz) and in radiation efficiency by 24.97% over conventional patch antenna can be achieved at 60.1 GHz. A gain enhancement of 2.64 dB is achieved with the recessed ground plane in the measurements. A good agreement between theoretical and measured results confirms the advantage of using the recessed ground plane.