Beam Steering Conformal Transmitarray Employing Ultra-Thin Triple-Layer Slot Elements

Abstract

A novel conformal transmitarray with beam steering ability is presented. First, an ultra-thin transmitarray element consisting of three layers of identical square ring slots is developed. The element has a thickness of 0.508 mm (0.04 wavelength in the free space at 25 GHz), achieving a transmission phase range of 330° with a maximum 3.6 dB loss. The element is then applied to a curved transmitarray conformal to a cylindrical surface fed by a standard gain horn with about a 10-dBi gain. A prototype is fabricated radiating a boresight beam with a peak measured gain of 19.6 dBi and an aperture efficiency of 25.1%. Second, when the transmitting surface of the above array is divided into two parts from the middle with different main beam directions, the combined beam can be radiated to an oblique angle with respect to the boresight direction. Using this method, a mechanical beam scanning conformal transmitarray antenna is designed. Its size is about 2.5 times larger than the fixed-beam one and consists of six transmitting surfaces with main beams directed to different angles. By rotating the feed horn to different positions, the main beam of the array can be switched to ±15°, ±10°, ±5° and 0°. A prototype is fabricated with a stable gain of about 18.7 dBi at all beam angles.

Quasi-Optical Multi-Beam Antenna Technologies for B5G and 6G mmWave and THz Networks: A Review

“…Two novel high-efficiency, and ultra-thin conformal transmittarray were introduced in [117], [118]. The ultra-thin conformal transmitarray consisted of three-layers of identical square ring slots.…”

An Elliptical Cylindrical Shaped Transmitarray for Wide-Angle Multibeam Applications

“…In this paper, the unit cell employed for the transmitarray is a triplelayer structure with three identical square ring slots printed on two substrates [30], as shown in the inset of Fig. 3.…”

“…A curved cylindrical transmitarray is demonstrated in [29], providing a simulated beam scanning range of 82° with a 3.9 dB scanning loss. Another cylindrical transmitarray [30] achieves a mechanical beam scanning range of ±15° using a superposition method. More specifically, its transmitting aperture is divided into six sectors with different beam directions.…”

True-Time-Delay Mechanical Phase Shifter in Gap Waveguide Technology for Slotted Waveguide Arrays in Ka-Band

“…One family of solutions achieves beam scanning by the relative movement of printed phase-shifting surfaces (PSS) or lenses over a primary feed. Firstly, as with parabolic reflectors, a mere translation or rotation of the feed produces the desired beam scanning performance [4]- [7]. Note that these solutions, as well as many others mentioned later, provide one-dimensional beam scanning along elevation plane whereas full azimuth sweep would be achieved by the antenna rotation.…”