Applying Massively Parallel Computing to Multiscale Ka Dual-Band Transmit-Array Analysis Using FETI-2LM

Abstract

Transmit-arrays (TAs) are a popular cost-effective solution for high-gain antennas at millimeter waves (mmW). The design of these antennas relies on the fine tuning of the subwavelength unit-cells that compose the aperture. The intricacy of the unit-cells increases as new features are implemented, such as dual-band operation and wide-angle beam steering, making this antenna even more computationally challenging. In this work, a high gain (25 dBi @ 20 GHz and 28 dBi @ 30 GHz) multiscale Ka dual-band TA for beam-steering applications is analyzed using a massively parallel implementation on multicores clusters of the Finite Element Tearing and Interconnecting method, with a two Lagrange Multiplier (FETI-2LM) technique. The main contribution of this work is the implementation of 3D non-periodic grids with sub-domains of different scales, that is suitable for proper modelling of different regions of the antenna (horn feed, lens cells, air region). An automatic batch file procedure is proposed for the TA meshing, allowing the limited set of constitutive unit-cells of the TA to be meshed separately. Additionally, we are using a block-Krylov strategy to efficiently capture the TA beam-steering capability, without restarting from scratch the interface problem for each feed position. Since other Finite Element Method (FEM) results were not accessible due the size of the problem, the FETI-2LM numerical results provided in this work are compared with other MultiLevel Fast Multipole Method (MLFMM) [1] and Transmission Line Modeling Method (TLM) [2] of CST Microwave Studio solvers, as well as with the measured results of the corresponding Ka dual-band prototype. The computational infrastructure has been used only a fraction of its capacity. Therefore, a much higher gain design (40 dBi) can be assessed, opening a new realm of applicability of TAs in the space segment usually occupied by reflector-based solutions.

Manufacture and Measurement of Circularly Polarized Ka-Band Radiating Elements for SatCom Wide-Angle Phased Arrays Tiles

“…Infinite array simulations are performed with the CST Microwave Studio simulation software during the design and optimization phase of both Rx and Tx cells. The final analysis of the Tx arrays is carried out with FETI-2LM Domain Decomposition Method (DDM) [5] running on High Power Computed (HPC) computers through GENCI grants.…”

“…ONERA's FACTOPO electromagnetic simulator using Domain Decomposition Methods (DDM) [5] is used for finite array simulations using a triangular mesh. Even if the array is of small size (8x8), the implementation of these simulations is done on a High-Performance parallel Computer (HPC).…”

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

“…Dual and multi-band designs have also been reported recently [108]- [110]. As the complexity and size of transmitarrays grow, more effective analyses and computation techniques will become necessary [111], [112]. A mmWave multi-beam transmitarray for Ka-band applications was reported in [113].…”

Hybrid Numerical Methodology for Efficient Design and Optimization of Transmit-Array Antennas, X-Band Application

“…The maximum axial gain calculated by the hybrid tool for a 1-bit compensation model is 21.88 dBi. In order to confirm the efficiency of the TA before manufacture, full wave simulations are carried out with the Finite Element Tearing and Interconnecting (FETI) method in the frequency domain developed in [32] and briefly presented in section IV [15]. During the FETI simulation, the 20x20 physical array is completed by 2 empty elementary cells of the same size all around the array in order to remove the absorbing boundary surface far away from the physical array.…”

“…For instance in [14], using FEKO's Method of Moments (MoM), a full wave simulation of a 30×30 reflect-array (analogous problem to a TA) in the Ka band takes about 27 hours of CPU time and 29.56 GB of memory. The work presented in this paper aims to propose a design and simulation methodology for large TA antennas that greatly reduces the full wave simulation efforts, which are however essential for the final analysis [15], thus reducing the time and memory consumption in the design phase of these antennas. Furthermore, this work also proposes the use of optimization techniques to achieve very low profiles for the final antenna, reducing the total occupied volume and allowing space constrained applications.…”