A Tiled C-Band Dual-Polarized 1-Bit Transmitarray

Abstract

An original structure of tiled transmitarray is presented, comprising a number of topologically similar unit cells arranged in arbitrary pattern within a planar array frame. Each unit cell represents a passive receiver-transmitter structure with integrated phase-shifter, fabricated in commercial 5-layer printed circuit board process, which can take either of two coding states corresponding to 0° or 180° phase shift imparted to the signal transmitting through the device. The unit cell design supports two orthogonal linear polarizations. An example of a 10x10 element 1-bit beam steering transmitarray operated in C-band is demonstrated by simulations and measurements. The proposed structure represents a cost-efficient solution for scalable transmitarrays and also for proof-of-concept experiments in research and education.

Characterization of Tiled Architecture for C-Band 1-Bit Beam-Steering Transmitarray

“…The model of a transmitarray, first presented by the authors in [10], is given below for consistency. In a spatially phase-modulated transmitarray, the normalized wave amplitude received by a unit cell from the focal source reads:…”

“…The effects of the element coupling Figure 1. One-bit dual-polarized tiled transmitarray architecture: (a) design of the array tile (vertically exploded view), comprising two identical proximity-coupled square-ring radiators on the opposite sides of the tile connected via two U-shaped feed loops; (b,c) schematic view of the surface currents on the proximity coupled feed loops and square-ring patches in two phase states, respectively (the ground plane is not shown); (d) a section of the tiled transmitarray partially assembled; (e) a section of the integral single-panel transmitarray; (f) proposed device architecture, [10], including individual unit cells (different colors indicate one of the two phase states) to be mounted in the plastic grid frame and spatially fed by a focal-source patch antenna.…”

“…Our research is aimed at adopting the transmitarray architecture for MIMO communications in C-band. In our previous publications [ 10 , 11 ], we reported on a low-frequency prototype of novel 1-bit dual-polarized tiled transmitarray, whereby the required phase distribution across the array aperture was built from standalone unit cells manufactured individually and assembled in the required pattern using a rectangular latticed plastic frame, Figure 1 . Some preliminary simulation and measurement results were presented, and it appeared that the tiled architecture can be a viable solution for fast prototyping and teaching experiments, without significant performance deterioration, as compared with a similar single-panel transmitarray.…”

Small-Size Square Ring 1-Bit Reconfigurable Transmitarray Unit Cell for C-Band Applications

“…The gain is 5.5 dB at the central frequency, while the gain loss due to mismatching is about 2.5 dB in 200 MHz (3.4%) frequency bandwidth. It should be noted that the structure can be modified by placing an additional coupling element to the vertical arm of the square ring antennas to provide dual-polarization operation [12]. The unit cell has been fabricated using a standard PCB process and characterized inside the waveguide.…”

“…Alternatively, the antennas can be coupled to each other asymmetrically, depending on the required phase shift. The interlayer connections can be implemented by aperture coupling or the plated vias [11,12]. The last one provides a more simplified way for phase switching.…”