High-Efficiency Dielectric Reflectarray Antennas With Ultra-Wideband Characteristics

Eun-Cheol Choi,Sangwook Nam

doi:10.1109/access.2021.3125458

Eun-Cheol Choi, Sangwook Nam

Open Access

https://doi.org/10.1109/access.2021.3125458

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Abstract

In this study, a K-band offset dielectric reflectarray antenna, having high aperture efficiency and ultra-wideband characteristics, was designed. A column-type dielectric unit cell was employed for the dielectric reflectarray elements. To obtain the ultra-wideband characteristics, an effective arrangement of the dielectric elements was implemented by considering the relative phase requirement. In addition, the real phase error and element patterns were calculated and analyzed using the equivalence principle and full-wave simulations. The prototype of the dielectric reflectarray antenna was fabricated by milling a dielectric sheet. The performance of the proposed antenna was measured and observed to be in good agreement with the simulation results. The measured results demonstrate that the maximum aperture efficiency was 63% at 22 GHz and bandwidth for an aperture efficiency exceeding 40% was 42.5%. The achieved results signified the importance of the arrangement strategy of the elements to achieve better efficiency and wider bandwidth performances.

Highlights

A reflectarray antenna combines the advantages of a parabolic reflector antenna and phased-array antenna [1]
The reflectarray antenna could achieve a high gain performance because the radiating elements compensate for the spatial phase delay from the feed horn at any target frequency
This bandwidth limitation is caused by two different factors viz., the narrow band of the radiating elements and the differential spatial phase delay according to the different paths from the feed horn to each position of the array surface [3−5]

Summary

Introduction

A reflectarray antenna combines the advantages of a parabolic reflector antenna and phased-array antenna [1]. The parabolic reflector antenna compensates for the phase delays of the different paths from the feed horn through the curved surface [2]. The reflectarray antenna could achieve a high gain performance because the radiating elements compensate for the spatial phase delay from the feed horn at any target frequency. When the frequency changes the gain of the reflectarray could significantly deteriorate This bandwidth limitation is caused by two different factors viz., the narrow band of the radiating elements and the differential spatial phase delay according to the different paths from the feed horn to each position of the array surface [3−5]. Various unit-cell structures have been used to obtain wideband characteristics [6−8] In these cases, widegain bandwidth was achieved by improving the parallel slope of the reflection phase with reference to the frequency variation rather than the S-shape reflection phase response

Objectives

Results

Conclusion