The gain effects of air gap quadratic aperture-coupled microstrip antenna array

This paper describes the concept of air gap structure to enhance the antenna's gain. The structure of the planar antenna array consisting rectangular16 elements is comprised based on corporate feed network. The advanced of this antenna design is the antenna's feeding network is etched on a difierent layer from the elements by certain of air gap distances. The air gap antenna was separated and measured from 0mm to 20mm, in 0.5mm increments respectively. Quadratic slots enabled most of the induced current and power from source to the radiating patches. The magnetic characteristics of quadratic allowed absorbing the re∞ected electrical flelds around the slots. The conflguration of air gap is competent in∞uencing a stronger fringing fleld at the edge of the patches. The fringing flelds become stronger as the distance is getting increased. A strong fringing flelds leads for the patches to radiate even further. The air gap increased the radiated power and reduced conductor loss. The gap coupling is more feasible to reduce surface wave excitation between elements which are separated by a ground plane. The combination of air gap structure with quadratic slots the gain grooming 400% times larger than a quadratic aperture coupled microstrip array antenna without an air gap. The proposed antenna also has signiflcant 50% of gain compared to the conventional transmission line antenna array. The air gap has successfully increased the level of isolation up to 1.5 times bigger than without air gap. The efiects of the gap on parameters such as radiation patterns and gain are observed. Good agreement between simulations and measurements is also obtained. These results extend the validity of the analysis and will be useful for higher gain applications.