Investigation of a miniaturized reflectarray antenna radiating in unusually tilted directions

Abstract

We investigate the overall performance of a miniaturized reflectarray antenna radiating in unusually inclined directions. In our previous work, we successfully reduced an overall electrical volume of a conventional reflectarray antenna by more than hundreds of times. In the previous work, beam scan directions were strictly limited on only one plane, i.e., an H‐plane which is a general beam scan plane for the used source half‐wavelength dipole antenna. However, for unrestricted beam control required to cover entire hemispherical radiation space, beam scanning on an E‐plane is also much required. Accordingly, we examine antenna gain and aperture efficiency for inclined radiation on an E‐plane, which is disadvantageous for the source dipole antenna. To minimize expected antenna gain decrease, each cell of the reflectarray is designed to present desired reflection phase which is required to provide constructive interference between direct and reflected waves coming from the dipole and the reflectarray, respectively. Consequently, even though the proposed antenna scans on an unusual E‐plane including a dipole axis, we can show our miniaturization method can still provide relatively high aperture efficiency, which is important to scan a main beam in any arbitrary directions collaborating on our previous work.