Oscar Borries

Head of Mathematics & AI Team

Education: PhD, MSc in Mathematics Specialization: Method of moments, scientific computing With TICRA since: 2011

Oscar is head of Mathematics & AI Team where he works on algorithm development for TICRA’s main software packages. Additionally, Oscar is Product Lead for Antenna Placement and Scattering. Oscar received his PhD in 2015, focusing on implementing the Multi-Level Fast Multipole Method (MLFMM) as well as accelerated evaluation of fields from surface current densities.

High-frequency CubeSat platform scattering using higher-order method of moments

We present a 10 cm offset reflector antenna mounted inside a 6U CubeSat platform and analyze the bare reflector and three reflector + CubeSat platform configurations in W band (86 GHz), where the CubeSat platform is electrically large. Using higher-order…

Reflector antenna optimisation with multi-level coordinate search

We review the key aspects of an optimisation algorithm when applied to challenging antenna design problems, and highlight the Multi-level Coordinate Search (MCS) global optimisation algorithm as an option in some scenarios. We present two comparisons which illustrate that MCS…

Uncertainty quantification for modern antenna systems

Many modern antenna systems, particularly for applications in telecommunication or earth observation, have significant mechanical complexity. This entails an often lengthy and detailed design process, where the design is carefully revised to ensure the best performance for the intended application….

RF Design Tool for end-to-end Optimisation of High-performance Multibeam Antenna Systems

This paper describes a new integrated RF design tool for analysis and optimisation of reflector-based multibeam antenna systems. The new tool combines several powerful algorithms into a flexible software framework that allows end-to-end optimisation of antenna systems comprising of passive…

Robust Optimization for Shaped Reflector Antennas

The shaping of reflector antennas in geostationary orbit to attain contoured beams on earth is most often done by solving a minimax optimization problem based on a Physical Optics analysis of the reflector antenna gain, cx-pol, e.t.c. Unfortunately, this optimization…

Uncertainty quantification for reflectarrays

Reflectarray antennas for space applications involve a large number of elements with varying sizes to be printed on a dielectric substrate. Due to the manufacturing process, the fabricated reflectarray might have significant deviations from the desired design. This paper demonstrates…

Direct optimization of quasi-periodic surfaces in multi-reflector systems

In recent years, there has been an increasing interest in replacing traditional periodic surfaces, e.g., frequency selective surfaces, with quasi-periodic surfaces (non-identical elements) in multi-reflector systems for satellite applications. Quasi-periodic surfaces can be used to improve existing antenna solutions or…

Advances in commercial software for high-gain antennas and electrically large platforms

We present the latest enhancements in the GRASP software package for analysis and design of electrically large antennas and platforms. The focus is on the hybridisation of efficient and accurate methods which allows antenna systems with very high complexity to…

Design of high-performance antenna systems with quasi-periodic surfaces

Periodic surfaces (identical array elements) have existed for several decades. However, in recent years, there is an interest in replacing such surfaces with quasi-periodic surfaces (non-identical array elements). Quasi-periodic surfaces provide additional degrees of freedom and can be used to…

Uncertainty quantification for reflector antennas

Large reflector antennas for telecommunication or space observation purposes often require a lengthy and detailed design process, where the design is carefully revised to ensure the best performance for the intended application. For many modern reflector antennas, quantification of the…

Efficient Monostatic RCS Calculation with Higher-Order MLFMM

The traditional O(f6) computational time scaling when using Method of Moments for monostatic Radar Cross Section calculations is circumvented by applying the Multi-Level Fast Multipole Method (MLFMM) along with a number of modifications. The performance of the modified MLFMM-based algorithm…

Efficient Surface Optimization of Large Dual Reflector Systems

Surface shaping of reflector antennas for creating a contoured beam is an ubiquitous task in the design of modern communication satellites. In this paper, we highlight two major improvements to the state-of-the-art that provides a major increase in computational efficiency—a…

Monostatic RCS Analysis of Electrically Large Structures using Integral Equations

The monostatic radar cross section (RCS) is an important design parameter for many applications but accurate RCS prediction of an electrically large structure continues to be a challenging task. High accuracy demands and a complicated geometry often mean that asymptotic…

High-Performance Curved Contoured Beam Reflectarrays with Reusable Surface for Multiple Coverages

An investigation of curved contoured beam reflectarrays with reusable surface for multiple coverages is presented. The main advantage of curved reflectarrays over shaped reflectors is that they allow the possibility of reusing a standard parabolic mold for multiple missions. To…

Efficient Optimization of High-Performance Contoured Beam Reflectarrays with Reusable Surface Shape for Multiple Coverages

This paper describes the design of high-performance contoured beam reflectarrays using a direct optimization technique with an improved optimization engine. In Ku-band, curved reflectarrays allow the reuse of a standard mold for multiple missions and thereby reduce cost and delivery…

Fast and Memory-Efficient Method for Full-Wave Analysis of Electrically Large Reflector Antennas and Satellite Platforms

We present a method that enables full-wave analysis of electrically large antennas and platforms, e.g., a detailed telecommunication satellite at Ka-band. Owing to the efficient formulation, even large problems can be solved on relatively modest computing platforms such as laptops…

Large-scale Optimization of Contoured Beam Reflectors and Reflectarrays

Designing a contoured beam reflector or performing a direct optimization of a reflectarray requires a mathematical optimization procedure to determine the optimum design of the antenna. A popular approach, used in the market-leading TICRA software POS, can result in computation…

Memory-efficient, full-wave analysis of waveguide scattering parameters for multiple reflector feeds mounted on electrically large satellite platforms

A Higher-Order Multilevel Fast Multipole Method (HO MLFMM) is presented for the efficient calculation of waveguide scattering parameters in cases where several reflector feeds are mounted on electrically large satellite platforms. The efficiency is obtained by: 1) using a Block…

New Analysis Capabilities for Electrically Large Antennas and Platforms

We present recent advances in the RF modelling of electrically large antennas and platforms, with an emphasis on reflector antennas and satellite platforms. The Higher-Order Multilevel Fast Multipole Method (HO MLFMM) was introduced recently in the commercial software tool GRASP,…

Full-wave Optimization of Large Compact Antenna Test Ranges

The challenges related to the increasing physical size of satellite platforms carry over to a number of related areas, including the design of Compact Antenna Test Ranges (CATRs) capable of handling such structures. In the present paper, we consider the…

Design and Validation of Compact Antenna Test Ranges using Computational EM

The design of modern Compact Antenna Test Ranges (CATRs) is a challenging task, and to achieve strong performance, simulation using computational electromagnetics is a vital part of the design process. However, the large electrical size, geometrical complexity and high accuracy…

Full-Wave Modeling of the PLANCK Space Telescope

Modeling the optical system on the Planck Space Telescope pre-launch was a very demanding task, with the huge electrical size, the strict accuracy requirements and the complicated feed arrangement all posing complications for efficient modeling. Pre-launch, the only viable option…

Higher-Order Method of Moments Analysis for Unconnected Quadrilateral Meshes

A higher-Order (HO) quadrilateral mesher is presented along with a HO method of moments formulation for unconnected meshes. A numerical example is presented to validate the new formulation. Publication: Proc. 2015 IEEE AP-S Symposium on Antennas and Propagation Place: Vancouver, British…

Design and Optimization of a Single-Layer Planar Transmit-Receive Contoured Beam Reflectarray with Enhanced Performance

This paper presents the design and optimization of a 1.2-meters single-layer planar contoured beam reflectarray in Ku-band. The reflectarray is optimized to fulfill the requirements of a Direct Broadcast Satellite mission, which covers a South American coverage in both transmit…

Analysis and Optimization of a Curved Transmit-Receive Contoured Beam Reflectarray

This paper presents the analysis and optimization of a 1 meter single-layer curved contoured beam reflectarray in Kuband. The curved reflectarray is designed to radiate a contoured beam over a European coverage in both transmit and receive frequency bands for…

New Fast and Robust Modelling Algorithms for Electrically Large Antennas and Platforms

This paper presents two new modelling algorithms that were recently added to the commercially available GRASP software package for electrically large antenna and scattering problems. In particular, a new higher-order multilevel fast multipole solver (HO-MLFMM) provides very high simulation accuracy…

Fast and Accurate Analysis of Reflector Antennas with Struts and Satellite Platform Scattering

This paper presents two methods related to modelling of reflector antenna struts and surrounding structural features such as satellite platforms. One method is a MoM-based strut model and represents an improvement of an existing PO-based model, thus enabling analysis of…

Detailed Pattern Computations of the UHF Antennas on the Spacecraft of the ExoMars Mission

This paper describes the pattern computations of the UHF antennas mounted on the spacecraft of the EXOMARS mission. The analyses are made by the higher-order Method of Moments (MoM) add-on to GRASP and are computed twice. In the first computation,…

Integral Equation Modelling of Reverberation Chambers using Higher-Order Basis Functions

Reverberation chambers (RCs) are important measurement facilities, and thus it is often required to simulate their behaviour numerically. However, due to their special characteristics, especially for high Q factors, they are often considered too challenging for application of standard numerical…

Adaptive Grouping for the Higher-Order Multilevel Fast Multipole Method

An alternative parameter-free adaptive approach for the grouping of the basis function patterns in the multilevel fast multipole method is presented, yielding significant memory savings compared to the traditional Octree grouping for most discretizations, particularly when using higher-order basis functions….

Multilevel Fast Multipole Method for Higher Order Discretizations

The multi-level fast multipole method (MLFMM) for a higher order (HO) discretization is demonstrated on high-frequency (HF) problems, illustrating for the first time how an efficient MLFMM for HO can be achieved even for very large groups. Applying several novel…

Gaussian Translation Operator for Multi-Level Fast Multipole Method

Results using a new translation operator for the Multi-Level Fast Multipole Method are presented. Based on Gaussian beams, the translation operator allows a significant portion of the plane-wave directions to be neglected, resulting in a much faster translation step. Publication:…

Reflector Antenna Analysis using Physical Optics on Graphics Processing Units

The Physical Optics approximation is a widely used asymptotic method for calculating the scattering from electrically large bodies. It requires significant computational work and little memory, and is thus well suited for application on a Graphics Processing Unit. Here, we…

Improved Multilevel Fast Multipole Method for Higher-Order Discretizations

The Multilevel Fast Multipole Method (MLFMM) allows for a reduced computational complexity when solving electromagnetic scattering problems. Combining this with the reduced number of unknowns provided by Higher-Order discretizations has proven to be a difficult task, with the general conclusion…

Improved Multilevel Fast Multipole Method for Higher-Order Discretizations

Higher-Order Basis Functions Applied to the Inverse Method of Moments for Inverse-Source Problems

Higher-order basis functions are commonly used for discretization of surface integral equations, which are typically solved by the Method of Moments (MoM). This leads to higher accuracy and lower memory requirements when compared to a simple piecewise linear discretization, e.g.,…

New Modelling Capabilities in Commercial Software for High-Gain Antennas

This paper presents an overview of selected new modelling algorithms and capabilities in commercial software tools developed by TICRA. A major new area is design and analysis of printed reflectarrays where a fully integrated design environment is under development, allowing…

Antenna Diagnostics on Planar Arrays Using a 3D Source Reconstruction Technique and Spherical Near-Field Measurements

In this paper, we apply a recently developed 3D source reconstruction algorithm to perform antenna diagnostics on a planar array configuration. The test case is a planar X-band slot array measured in a spherical near-field facility and two slots were…

A Novel Accurate Pattern Fitting of Noisy Irregular Beam Data for the Planck Space Telescope

Kriging fitting, originally developed for geological exploitation, is here applied for fitting an expected pattern to noisy, irregular in-flight measurements of a satellite antenna. The noise level in in-flight measurements is often so high that only the central part of…

Processing of Measured Fields Using Advanced Inverse Method of Moments Algorithm

A higher-order inverse method of moments algorithm, employing smooth current and geometry representations, as well as a very noise-robust solution algorithm, was presented at last year’s ESA workshop. The fundamental properties of the algorithm, including quantitative results for the RMS…

Grating-Lobe Pattern Retrieval from Noisy Irregular Beam Data for the Planck Space Telescope

In-flight measurements of satellite antenna patterns are often given in a highly irregular grid and the data may be influenced by severe noise such that an accurate pat-tern determination is difficult. In this paper, a two-step fitting algorithm for retrieval…

Accurate Fitting of Noisy Irregular Beam Data for the Planck Space Telescope

Accurate fitting of the noisy irregular amplitude only main beam data is essential for the retrieval of the Planck space telescope geometry. Therefore, a novel two-step fit-ting algorithm which focuses on the spatial dependency of the in-flight measurements has been…

Model-Based System Engineering Components of Antennas

Very sophisticated antenna models are available today for the accurate prediction of antenna performances, in particular those included in the European Antenna Modeling Library in which GRASP, ADF and SATSim are key components. However these models are not directly suitable…

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