Holographic transmitarray antenna with linear polarization in X band

Mahdi Salehi,Homayoon Oraizi

doi:10.1016/j.aeue.2022.154115

Abstract

For the first time, we present the design and demonstration of holographic transmitarray antennas (TAs) based on the susceptance (reactance) distribution in this paper. According to the holographic theory, the amplitudes and phases of electromagnetic waves can be recorded on a surface, and then they can be reconstructed independently. This concept is used to design single-beam and multi-beam linearly polarized holographic TAs without using any time-consuming optimization algorithms. Initially, an impedance surface is analyzed for both transmission and reflection modes. As there are differences between the susceptance (reactance) distribution of these modes, a new approach (different from reflectarray designs) is proposed to apply the holographic technique to transmitarray designs. Then, interferograms are described based on the scalar transmission susceptance distribution according to the number and direction of the radiation beams. Subsequently, a transmission metasurface of dimensions equal to 0.26λ0 is hired to design holographic TAs at 12 GHz. Several holograms are designed using the unit cell to verify the proposed method. Finally, as a proof of concept, a linearly polarized circular aperture wideband holographic transmitarray antenna with a radius of 13.3 cm is manufactured and tested. The antenna achieves 12.5% (11.4-12.9 GHz) 1-dB gain bandwidth and 23.8 dB maximum gain, leading to 21.46% aperture efficiency. Furthermore, the antenna achieves 95.94% simulated radiation efficiency mainly due to using subwavelength elements, which becomes possible by applying the holographic technique.

Highlights

Transmitarrays have attracted much interest in recent years because of their inherent advantages such as high gain, high radiation efficiency, lightweight, low profile, and simple manufacturing procedure, making them the right candidate for satellite communication, microwave imaging system, and radar applications
We present the design and demonstration of transmitarray antennas (TAs) based on the holographic technique for the first time
A holographic TA using the unit cell shown in Fig.3a, and Fig.3b is designed and manufactured

Summary

Introduction

Transmitarrays have attracted much interest in recent years because of their inherent advantages such as high gain, high radiation efficiency, lightweight, low profile, and simple manufacturing procedure, making them the right candidate for satellite communication, microwave imaging system, and radar applications. As a transmitarray is illuminated directly from the back of the aperture, it does not experience the blockage losses expected with reflectarray antennas. In2, two holographic reflectarray antennas with linear and circular polarizations are proposed. In3, a multi-beam linearly polarized holographic reflectarray antenna is proposed. It achieves 22.2% 1-dB gain bandwidth and 53.09% aperture efficiency for dual beam radiating. In4, a circular polarized holographic reflectarray antenna is proposed. The antenna can produce multiple beams with independent circular polarizations. It achieves 19.23% 1-dB gain bandwidth and 45.8% aperture efficiency. The antenna can produce multiple beams with arbitrary shapes. In [6-10], holographic leaky wave antennas are proposed

Methods

Results

Conclusion