Gain enhancement of a slot antenna using multiple metasurfaces

We present in this paper a design of a high gain antenna for radar-based non-contact measurement systems in the k-band frequency. The proposed antenna consists of a slot on a multi-grooved metal structure (flange) and a frequency selective surface (FSS) acting as a flat lens. Often, grooved (or corrugated) surfaces and frequency selective surfaces are used to enhance antenna gain features. The combination of these two techniques could provide more gain with a small size antenna. In this sense, dimensions of both grooves and FSS are optimized to reach the maximum gain without increasing the size of the antenna. All simulations and optimizations are carried out using electromagnetic full-wave tools. Next, a prototype of the proposed antenna is manufactured and characterized. More than 15 dB of gain is obtained over the whole bandwidth with a peak gain of about 17.5 dB is measured around the frequency 24.5 GHz.