Dr. Rob Maaskant
 (A
ssociate Professor)

 

Brief CV - Curriculum Vitae


Rob Maaskant was born in the Netherlands on April, 14th, 1978. He received his MSc degree (cum laude) in 2003, and his PhD degree (cum laude) in 2010, both in Electrical Engineering from the Eindhoven University of Technology, The Netherlands. From 2003-2010 he was employed as a Researcher at the Netherlands Institute of Radio Astronomy (ASTRON), The Netherlands, and from 2010-2012 as a postdoctoral researcher at the Chalmers University of Technology, Sweden, for which he received a Marie-Curie (Rubicon) postdoctoral fellowship from the Netherlands Organization for Scientific Research (NWO). He won the 2nd best paper prize (best team contribution) at the 2008 ESA/ESTEC workshop, Noordwijk, and has been awarded the prestigious prize of the best PhD project in 2010 of the TU/e Electrical Engineering Department. He has published more than 100 journal and conference papers, and is holder of 8 patents or patent applications. He is the primary author of the CAESAR software; an advanced integral-equation based solver for the analysis of large antenna array systems, which is being used by several international research institutions. As an Assistant Professor he received the prestigious "Young Researcher" grant from the Swedish Research Council (VR) in 2011. He is currently an Associate Professor in the Antenna Group of the Electrical Engineering Department at Chalmers (Sweden) as well as in the Electromagnetics Group of the Eindhoven University of Technology (TU/e, The Netherlands). He has received a Vidi grant from NWO in 2016 for realizing novel mm-wave integrated antenna and microwave structures in collaboration with NXP and Ericsson. He has been elevated to Senior Member IEEE in 2013, and served the AP community as an Associate Editor for the IEEE Transactions on Antennas and Propagation, the IEEE Antennas and Wireless Propagation Letters, and the Forum for Electromagnetic Research Methods and Application Technologies (FERMAT, http://www.e-fermat.org).

 
PhD Thesis   : click here to view Maaskant's PhD Thesis



Chalmers University of Technology
Department of Electrical Engineering
41296 Göteborg
Sweden

Eindhoven University of Technology (TU/e)
Department of Electrical Engineering
Postbus 513
5600 MB Eindhoven
The Netherlands

Tel: +46 732 366 102
e-mail: rob.maaskant@chalmers.se | r.maaskant@tue.nl



Visiting our Group


  • Potential students: If you are a strong and motivated student you are more than welcome to join our research team. I will supervise students at both Master and PhD level. For PhD students: there is a dual degree arrangement in place between Chalmers and the TU/e. PhD candidates should apply via the Chalmers and TU/e websites (https://www.chalmers.se/en/about-chalmers/vacancies/Pages/default.aspx ; https://www.tue.nl/en/university/working-at-tue/jobs/ , respectively). If there are no vacancies listed, this means that there are no openings at that time.
  • Visiting MSc / PhD students: We continually have a limited number of openings for visiting MSc and PhD students. Recommended duration is 1-6 months. We cannot offer financial support, but will provide office space, access to University facilities, and a stimulating research environment. Feel free to contact me with a concrete research and publication plan.
  • Postdoctoral researchers: We have occasional opening for postdoctoral researchers, which will be announced here. However, you may consider applying for a Marie Curie fellowship (see http://ec.europa.eu/research/mariecurieactions/ and click "When to apply"). In addition, the Swedish Research Council (see https://www.vr.se/english.html) sometimes awards 2-year postdoctoral fellowships. Should you be interested in applying please get in touch and we can assist you. More information: post-doc funding Jan 2018.pdf
  • Visiting faculty: If you are interested in visiting the Department of Electrical Engineering for a short-term research stay, we can offer limited financial support. Feel free to get in touch for further information.

Projects



 


VIDI project  

Packaging and Integration of mm-Wave Antennas and Chips


The research into mm-wave technology is being pushed by a world-wide need to develop next generation wireless systems. These systems are small in size, offer large frequency bandwidths, are cost-effective and allow for high degree of electronic system integration. The current integration and packaging concepts of antennas and electronics are plagued by cross-talk effects and cavity resonance issues and a limited overall performance. Ultra low-loss metal-only antennas are preferred, but these cannot be connected directly to integrated circuits. A breakthrough in the mm-wave domain is urgently needed to overcome these problems. Innovative system integration concepts are proposed that are based on the hybridization of circuit and quasi-optical wave models. The proposed solution avoids the use of RF bondwires (contactless interconnects) which may otherwise lead to spurious radiation, increased mismatch effects and power losses. Furthermore, recently developed low-loss metamaterial technologies has now enabled us to allow for a cross-talk and resonance-free packaging of circuits and antennas. In-house specialized numerical techniques will be used to develop new and fast optimization approaches for electrically large antenna arrays packaged with front-end electronics. Several prototypes will be designed to showcase the newly proposed system integration concepts and the impact thereof for many mm-wave applications and future research into sub-mm wave systems. The project makes use of the excellent infrastructures in both the Netherlands and Sweden: TU/e + NXP + ASTRON; Chalmers + Ericsson + Gapwaves.

Project Leader    : Assoc. Prof. Rob Maaskant
PhD1                 : Alhassan Aljarosha (EM group, TU/e; Antenna group, Chalmers)
PhD2                 : Piyush Kaul (MsM group, TU/e)
Promotor 1         : Prof. Bart Smolders (TU/e)
Promotor 2         : Prof. Marion Matters-Kammerer (TU/e)
Promotor 3         : Prof. Marianna Ivashina (Chalmers)
Image result for nwo logo    Image result for tue logo


Project period: 2017 -- 2021



 
 
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The SILIKA Training and Research Program

Silicon Based Ka-band massive MIMO antenna systems for new telecommunication services

http://silika-project.eu/

The continuously growing need for higher data-rates and, therefore, more signal bandwidth in wireless communications, requires the use of multi-antenna base stations employing the recently introduced massive Multiple-Input-Multiple-Output (MIMO) concept and operating at millimeter-wave frequencies, e.g. 30 GHz. However, the implementation of such complex antenna systems into highly-integrated, energy- and cost-effective solutions is very challenging. Therefore, we propose an innovative antenna system concept utilizing silicon semiconductor electronics that can generate or receive at millimeter-wave frequencies in order to truly expand wireless communications into the outer limits of radio technology. 

The main research objectives of SILIKA is to develop innovative integrated antenna systems for future 5G base stations operating at millimeter wave (mm-wave) frequencies utilizing highly-integrated and cost-effective silicon (Bi-) CMOS technologies. These antenna systems will rely on the use of multi-antenna massive MIMO concepts in which the number of individual antenna elements in the base station is much larger than the number of users. In state-of-the-art phased arrays, only a limited number of identical antenna beams are used, usually operating in a single frequency band. Multi-antenna massive MIMO systems, however, can generate multiple beams, each with different shape operating at different frequencies, using polarization agility and adaptive waveforms.

Multi-element antenna systems are expected to increase the energy efficiency of future base stations, while achieving high data rates with indoors and out-door coverage both for line-of-sight and non-line-of-sight propagation conditions, by sending out many independent data streams to simultaneously serve many users. The proposed design methods in SILIKA aim at synthesizing energy-efficient multi-beam array antennas, while minimizing the detrimental effects of electromagnetic mutual coupling between the array antenna elements.


Project period: 2017 -- 2020


 

 


A ChaseOn Research Centre Project

Integrated Array Antennas

The aim of this project is to develop the required interdisciplinary design methodologies for integrated array antennas (iAAs) that are capable of accounting for critical interactions between antennas and electronics and to explore practical and fundamental limitations of large-scale, beam-steering array antennas for wireless and space communication and defense applications. To achieve the aims, we consider three objectives:

  • Determine physical fundamental limitations of iAAs bounding their main parameters to predict their impact on the system performance
  • Develop accurate and computationally efficient models to include the effects of array front-end electronics in the optimization of iAAs
  • Investigate novel antenna array integration concepts and test their potential


Project period: 2017 -- 2020





My Research Team Members



 


Ph.D. Student     : Alhassan Aljarosha (Vidi project)
Project title         : Packaging and Integration of mm-Wave Antennas and Chips

Please see the above Vidi project description for more information. Alhassan is an electromagnetics (EM) specialist focusing on the wave propagation and radiation from mm-Wave antenna and waveguide structures. He works in close collaboration with PhD student Piyush Kaul, see below, to facilitate a contactless transition from waveguide to Silicon-based integrated circuits via quasi-optical techniques.


Project period: 2017 -- 2020
 


 
 


Ph.D. Student     : Piyush Kaul (Vidi project)
Project title         : Packaging and Integration of mm-Wave Antennas and Chips

Please see the above Vidi project description for more information. Piyush is an integrated circuit (IC) specialist focusing primarily on the mm-Wave power generation of Silicon-based MMICs employing both series and parallel on- and off-chip power combining techniques. He works in close collaboration with PhD student Alhassan Aljarosha, see above, to facilitate a contactless transition from waveguide to Silicon-based integrated circuits via quasi-optical techniques.


Project period: 2017 -- 2020


 
 


Ph.D. Student     : Wan-Chun Liao (ChaseOn project)
Project title         : Integrated Array Antennas

The goal is to develop a design flow to optimally impedance-match a power amplifying Integrated Circuit (GaN IC) directly to an array antenna element, thereby avoiding relatively lossy 50-Ohm matching networks while potentially increasing the frequency bandwidth at the same time. This requires a co-optimization approach of both the IC and the antenna, each having their own mutually-dependent design constraints. We will consider linearity, radiated output power (EIRP), power efficiency, cooling aspects, and array mutual coupling effects. The project focuses on 15--40 GHz applications. Yet, Wan-Chun is also involved as a consultant to the project of Divya Jayasankar which focuses on <6 GHz frequencies, see below.



Project period: 2017 -- 2020


 

 


Ph.D. Student     : Navid Amani (Silika project)
Project title   : Advanced System-Level Design Approaches for Irregular Array Architectures

The goal is to examine the most promising irregular sparse array (ISA) architectures in order to identify both fundamental and practical limitations of such antenna systems for Massive MIMO applications. To achieve this goal we will employ a holistic system-level approach to characterize MIMO transceiver base station antennas in two extreme propagation scenarios of a 'real-life' channel, i.e., the so-called edge reference environments: Rich Isotropic Multipath and Random Line-of-Sight. Experimental system-level validation will be done using a system-level test-bed using a quad-mode antenna which when placed in an array environment is capable of detecting two orthogonal field components over a nearly hemispherical coverage, while providing four independent data streams per antenna element. The element geometry and array layout will be optimized by using the compressive sensing approach for the synthesis of maximally sparse arrays in the presence of antenna mutual coupling. The optimization goal is to achieve maximum MIMO throughput bandwidth, defined based on the MIMO efficiency in both edge environments. Integration of concepts into the yet to be developed Silika system simulation platform is planned as well.



Project period: 2017 -- 2020


 

 


Ph.D. Student     : Artem Roev (Silika project)
Project title       : Contactless Passive and Active Connections Between Antennas and Transmitter Integrated Circuits

This project aims to examine mm-wave power transmitters using emerging low-loss dielectric-free metamaterial technologies for the integration and packaging of array antennas and electronics to mitigate the problems of conventional approaches causing cross-talk effects and cavity resonances. We will employ these novel technologies to design a mm-wave distributed silicon-based power grid amplifier with high-gain performance. This design process will include the following steps: (i) conceptual studies of distributed silicon amplifiers to decide on most promising architectures; (ii) semi analytical-numerical simulations to select the best topology that is suited for large scale deployment of metal-only antenna arrays; (iii) Optimized design and prototype of transmitters based on efficient silicon ICs and splitter/combiners using the contactless packaging concept, where specifications from the other Silika sub-projects are used, and (iv) experimental verification of the contactless EM packagning concept and integration into the development platform (Silika system simulator).


Project period: 2017 -- 2020



 
 

M.Sc. Student   : Divya Jayasankar (Initiate project)
Project title       : An Active Planar Inverted-F Antenna

This project explores the possibilities of designing a compact and low-cost planar inverted-F antenna for wireless communication applications. The design supports the direct integration with electronics (see the above PhD project Wan-Chun Liao) and offers harmonic tuning possibilities for achieving high power added efficiency. The effect of the antenna array mutual coupling will be examined afterwards. The project focuses on frequencies below 6 GHz.


Project period: 2017



Finalized Projects / Alumni


 


Ph.D. Student     : Carlo Bencivenni (Chase project)
Project title   Next Generation Array Antennas for Satellite and Mobile Communication Systems

The goal of this PhD project is to develop a generic design methodology for sparse aperiodic array (SAA) antennas for future satellite and mobile communication systems. This work is part of the CHASE Research Center project termed "Next Generation Array Antennas" and is a joint collaboration between the Royal Institute of Technology (KTH) and two industrial partners: Ericsson AB and RUAG Space AB.

This PhD project consists of the development of iterative algorithms to synthesize SAA antenna configurations, where the key novelties are: (i) antenna mutual coupling is included during the optimization; (ii) domain-decomposition-based EM simulations are combined with array signal processing techniques; (iii) optimal arrays can be synthesized for arbitrary complex excitations or those having equal amplitudes; (iv) arrays are optimized for multiple scan angles at once; (v) a mask on the side-lobe level is imposed as a constraint in the optimization approach; (vi) multiple element types and multi-mode antenna elements can be considered; and (vii) optimal arrays can be synthesized for multiple beam shapes.




Project period: 2012 -- 2017



 
 


Ph.D. Student : Oleg Iupikov
Project title     : Sensitivity Modeling of Imaging Antenna Array Systems

The goal of this PhD project is to develop fast numerical approaches for the analysis and optimization of phased array feeds (PAFs) for reflector antennas to be used in radio telescopes and passive remote sensing systems, such as spaceborne microwave radiometers. This work is funded by the Swedish Research Council (VR, Vetenskapsrådet) and supports the radio astronomy research in the context of the next generation radio telescope, known as the Square Kilometer Array (SKA, http://www.skatelescope.org). It is also supported by the European Space Agency (ESA) through the Earth Observation programme, and is carried out in collaboration with TICRA (Denmark) and DTU-Space (Denmark).

The challenge of designing PAFs for radio telescopes is to account for the effects of array element mutual coupling and feed-reflector interaction in the analysis and optimization of the overall system performance. The challenge of the PAF design for spaceborne radiometers is to optimally match the array performance to the highly complex reflector configuration (such as a torus reflector) as well as to realize a very clean beam shape. Both application areas require multiple simultaneously formed and closely overlapping beams over a wide field of view. 

The research involves the development of an iterative hybrid method-of-moments (MoM) and physical optics (PO) formulation, which is further enhanced by FFT and near field interpolation techniques, as well as the Characteristic Basis Function Method (CBFM). This modeling framework allows for a detailed analysis of the EM characteristics of entire antenna (array) feed reflector systems; novel iterative Krylov subspace methods. The current activities focus on the design of optimal array layouts and beamforming algorithms for different types of spaceborne radiometers, including traditional conical scanner and more complex pushbroom systems.

Link to Licentiate Thesis


Project period: 2011 -- 2017




  



M.Sc. Student : Nikolaos Kollatos
Project title      : 
A Deeply Integrated Active Antenna

This project goes beyond what is commonly called 'strongly integrated antennas systems'. When the system becomes so strongly integrated it becomes impossible to separate antenna-amplifier-beamformer components from one another. In this project we will realize the system in a distributed sense to yield a single multifunctional EM component through what we call: 'deep integration'. This M.Sc. project is on realizing the first active prototype antenna based on the deep integration concept. It will form the foundation for what could become the next step in integrated antenna systems and associated modeling methods. Highly power efficient active antenna systems overcoming fundamental bottlenecks in terms of power generation/handling at mm-wave/sub-THz frequencies are among the possibilities.

Project period: 2017




 



M.Sc. Student : Waqar Ali Shah
Project title    : 
Millimeter-Wave Spatial Power Splitting and Combining for use in Gap-Waveguide-Integrated Grid Amplifiers and Antenna Arrays

Conventional power splitters and combiners employing substrate-based transmission lines suffer from both conductor and dielectric losses, in particular at mm-wave frequencies. These losses increase when the number of channels increase, thereby reducing the efficiency even further. The primary aim the thesis work is to minimize these losses by spatially power combining (or splitting) the electromagnetic fields in air-dielectrics. This will be done in a planar fashion and be packaged at the same time using gap-waveguide technology. Spatial power combining techniques are also used in grid amplifiers. Conventional grid amplifiers typically employ different feed networks including both dielectric lenses and polarizers, which are bulky and lossy and suffer from DC biasing problems. To overcome these problems, we propose to split and combine the power through a reflector-wall-based back-to-back gap waveguide structureThis work is important because it represents a low-loss power splitting and combining solution for mm-wave systems. It also forms the basis for a mm-wave grid amplifier in gap waveguide technology and in the long run -- at sub-mm wavelength frequencies -- it becomes a cost-effective solution as an all-integrated system on chip. Moreover, a low-loss transition from the chip to the outside world becomes unfeasible, so that waves on chips are the future, and these are the first steps toward that technology. Combining wave and particle models will lead to a breakthrough in the mm- and sub-mm wave domain. The proposed concept has been validated through numerical simulations and measurements with a prototype system as shown below.

Project period: 2015







 




M.Sc. Student : Alhassan Aljarosha
Project title   : 
A Packaged mm-Wave Contactless Microstrip Line to Groove Gap Waveguide Transition Suited For MMIC Integration

Realizing a low-loss transition of the electromagnetic fields from a metal-only waveguide structure to a transmission-line on a chip is a major challenge at mm-wave frequencies. Such transitions typically suffer from Ohmic losses, impedance mismatch effects, a limited frequency bandwidth, and spurious radiation of bondwires and cross-talk effects inside an enclosure when packaged. This project considers a contactless metal waveguide to chip transition which is very low loss. It also represents a resonance-free packaging solution of integrated circuits. The animation shows how the field is guided through the ridge waveguide structure. Note the guided waves-on-chip phenomenon and the similarity with fibers in the optical domain; the simulated port reflection is smaller than 1% and the power transmission coefficient is larger than >99% over the entire W-band. It is foreseen that this technology is going to lead to a breakthrough in the mm- and sub-mm wave frequency bands. At sub-mm wave frequencies it is envisioned that the entire technology can be integrated in a cost-effective manner onto a physically small (but electrically large) chip through a micromachining process. Such technologies will enable low-loss mm-wave systems, high SNR receiving antenna systems, and ultra fast communication links.

Project year: 2015





  

 


Ph.D. Student : Aidin Razavi
Project title     : Near Field Detection of Foreign Objects in Homogeneous Media

The goal of this PhD project is two-fold: (i) to develop an RF antenna detection system to identify foreign objects in homogeneous media. The targeted application is "food radar", where potential hazardous foreign objects need to be detected, so that appropriate action can be taken afterwards. The detection system comprises of both receiving and transmitting antenna arrays that need to be designed such as to maximize the probability of detection. To this end, the transmitting and receiving antennas are maximally coupled and, in conjunction with suitable array signal processing techniques, an optimal antenna array detection system is synthesized. (ii) the characterization of radio channels for over-the-air (OTA) applications. A typical scattering environment is emulated and characterized using in-house developed computational electromagnetics software. The percentage of RIMP (rich isotropic multipath) and RLOS (random line of sight) are quantified as a function of frequency, scattering positions, and the positions and types of receiving and transmitting antennas.



Project period: 2011 -- 2017




 

Ph.D. Student  : Andre Young
Project title  : Improving the Direction-Dependent Gain Calibration of Reflector Antenna Radio Telescopes

(Stellenbosch University, South Africa, group of Prof. David Davidson)

Development of several beam modeling methods, among which the newly proposed physics-based Characteristic Basis Function Pattern Method (CBFPM). This type of parametric beam modeling is essential for the efficient beam calibration of imaging array systems and constitutes a new research field. It is pointed out that, since the proposed modeling framework is generic, it can be applied to many other beamforming array systems, both in the receiving and transmitting situation.

Furthermore,
the concept of a shaped PAF which conforms electrically and/or geometrically to the focal arc of a reflector antenna has been examined, thereby eliminating intrinsic deformations of off-axis beams due to the presence of the parabolic reflector. Uniformity of the beams will ease the beam calibration and, in turn, lead to a higher dynamic range (sensitivity). The overlap of uniform beams improves the intrinsic continuity of the field of view. As a result, many degrees-of-freedom in the beamformer can be used for beamforming purposes other than for beam-distortion correction.


PhD Thesis   : click here to view Andre's PhD Thesis

Project period: 2011 -- 2013



 

Post. Doc.     : Dr. Andre Young
Project title    : Direction-Dependent Gain Calibration Using the CBFP Method

(Stellenbosch University, South Africa, group of Prof. David Davidson)

Further development and practical application of the newly proposed physics-based Characteristic Basis Function Pattern Method (CBFPM). This type of parametric beam modeling is essential for the efficient beam calibration of imaging array systems and constitutes a new research field. It is pointed out that, since the proposed modeling framework is generic, it can be applied to many other beamforming array systems, both in the receiving and transmitting situation.

In this project, the CBFP Method will -- for the first time ever -- be applied in practice to the LOFAR radio telescope at the Onsala Space Observatory.

Project period: 2014





M.Sc. Student : Majid Naeem
Thesis title      : Scattering and Absorption Analysis of Radomes Using the Method of Equivalent Dipole Moments
 
In radio astronomy applications, it is often essential to accurately evaluate the electromagnetic scattering and power dissipation losses of nearby dielectric objects, such as radomes. However, the numerical analysis becomes a burdensome task for most commercially available CEM tools when the dielectric becomes thin, complex shaped, and electrically large. To mitigate these problems, we propose to employ high-resolution basis functions for the accurate modeling of the volume equivalent currents. These basis functions are fractions of wavelengths in size and therefore called micro-domain basis functions. Because of their small sizes, each micro basis function can be simply represented by a cubic volume of uniform current with the advantageous property that the self term can be computed analytically by accounting for the static part of the Green's function only. Moreover, the coupling terms (off-diagonal moment matrix elements) can be computed through the dipole representation of the source basis functions in conjunction with the collocation method for testing this field (this is equivalent to Galerkin's method when selecting the midpoint integration rule). All together, these simplifications ease the code implementation significantly, however, the penalty is an increased memory storage requirement and a larger moment matrix fill-time due to an increased number of basis functions. The Multi-Level Characteristic Basis Function Method (MLCBFM) is then used to reduce the size of the moment matrix equation such that it can be solved in a direct manner, and in-core, for multiple right-hand sides, while the moment matrix filling is speeded up through the Adaptive Cross Approximation (ACA) algorithm. In conclusion, the proposed method allows for a fast and accurate solution of scattering problems for large and complex-shaped objects.

Project duration: 2010 -- 2011

Naeem's MSc Thesis
 
Figure: MoM (numerical) and MIE (analytical) scattering solution for a dielectric sphere (R = lambda/50, epsr = 6), for an x-polarized plane wave traveling along z. 12507 micro-basis functions are employed for the plain MoM approach, i.e. the zeroth level of a MLCBFM.

ICEAA 2011 conference paper




 

M.Sc. Student : Pegah Takook
Thesis title      : Fast Analysis of Gap Waveguides using the Characteristic Basis Function Method and Advanced Green's Function Approaches
 

There is an urgent need to develop customized computational electromagnetic (CEM) codes to expedient the numerical analysis of the next generation waveguiding structures. These so-called gap waveguides are novel low-loss low-cost nondispersive transmission lines that are well-suited for various future high-frequency applications. At this moment, however, the numerical analysis using commercially available CEM software tools is a very time-consuming - if not impossible - task. This is caused by the tiny geometrical details that the gap waveguide exhibits which, in turn, requires a fine discretization of the geometrical structure and Maxwell’s field equations. On the contrary, the whole structure itself can be electrically large and thus represents a multiscale problem. This leads to an extremely large matrix equation requiring huge amounts of RAM memory and very large solve times.

 

To allow for a fast numerical analysis (and optimization) of these gap-waveguide structures, it is proposed to employ advanced Green’s function approaches to analytically account for the EM fields generated by an elementary current inside a perfect electrically conducting enclosure (rectangular box and/or parallel plates). Accordingly, an integral equation is formulated for the total unknown current. The method-of-moments is then used to discretize the integral equation to arrive at a relatively small matrix equation. The size of this matrix equation can be reduced further by employing the Characteristic Basis Function Method. The resulting system of linear equations can then be solved very rapidly.

 

It is important to develop this dedicated software tool as it is key to the research and development of this novel gap-waveguide technology.
 
Project duration: 2011 -- 2012




 

Ph.D. Student : Danie Ludick
Project title    : 
Efficient Numerical Analysis of Finite Antenna Arrays Using Domain Decomposition Techniques

(Stellenbosch University, South Africa, group of Prof. David Davidson; EMSS FEKO)

The numerical analysis of large and finite array geometry is of interest to various research groups – not just in the industry, but also in the academic sector. An example of such a project is the Square Kilometre Array (SKA) radio telescope being constructed in South Africa and Australia. Simulating these structures can often place a considerable burden on computational resources in terms of both memory and run-time. This PhD dissertation is focused on alleviating this cost by applying efficient domain decomposition techniques, such as the Numerical Green’s function (NGF), the Domain Green’s Function Method (DGFM), the well-known Characteristic Basis Function Method (CBFM), as well as to develop an hybridized approach that combines the benefits of the aforementioned methods.

Project period: 2010 -- 2014




 

Ph.D. Student : David Prinsloo
Project title     : 
Mixed-Mode Sensitivity Analysis of Active Antennas

(Stellenbosch University, South Africa, group of Prof. Petrie Meyer)

This project considers antennas fed differentially with differential low noise amplifiers (dLNAs). In dense antenna arrays, such as the aperture arrays (AAs) proposed for the mid-frequency band of the Square Kilometre Array telescope, the AAs and the dLNAs feeding the individual elements cannot be considered separate from one another and neither can the differential and common-modes that propagate between them. In order to quantify the effect both propagation modes have on the system sensitivity a mixed-mode, multi-port signal and noise analysis of the differentially fed active antennas has to be performed. The design and analysis of a new type of dual mode (common + differential mode) antenna having an almost hemispherical field-of-view coverage pattern forms an important part of the project.

Project period: 2011 -- 2014




 

Ph.D. Student : Theunis Beukman
Project title     : 
Differential Quad-Ridged Horn Antenna and Amplifier Integration

(Stellenbosch University, South Africa, group of Prof. Petrie Meyer)


This project consists of the investigation and design of microwave networks that allow integration of differential low-noise amplifiers (dLNAs) and single-pixel feeds proposed for the 1--10 GHz band of the Square Kilometre Array (SKA) radio telescope. A new type of reflector antenna feed has been proposed: a differentially excited quad-ridged horn antenna, providing a more constant beamwidth over frequency as well as demonstrates an improved symmetrical beam properties as opposed to more conventional coaxial-probe-excited horn feeds.

The project involves a detailed theoretical analysis of the modal content of the fields in the horn antenna, amplifier-antenna integration aspects, and a sensitivity analysis when used in a reflector antenna system.

Project period: 2011 -- 2014





 

M.Sc. Student : Carl Toft
Project title      : 
Moment Method Analysis of Slot Coupled Waveguides

Satellite communication systems employ waveguide technology to transport signals from one microwave component to another. This project specifically is about the accurate numerical analysis of the electromagnetic coupling of waves between waveguide sections through slots. The method of moments code to be developed should account for both polarizations of the field in the slots and also include the thickness of the slot metals. This code is very efficient and accurate and forms a smaller though important part in the full system optimization software that is being used at RUAG Space.

Project period: 2014



 

M.Sc. Student : Stellan Johansson
Project title      : 
Sparse Antenna Array Synthesis for Satellite Applications

This thesis work aims at the design, manufacturing, and measurement of a demonstrator employing sparse antenna array technology within the Chase Research Center project called "Next Generation Array Antennas (NGAA)". This work is carried out in collaboration with RUAG Space AB. Our in-house numerical software tool (CAESAR) is used for the electromagnetic array design. It has been developed specifically for analyzing large antenna arrays in a time-efficient manner. It also interfaces with our in-house developed array thinning toolbox (see Carlo's project above), which renders the simulation package totally unique. Validation of subcomponents is partially done through the commercially available software FEKO.

Project period: 2014




 

Post. Doc.  : Dr. Elena Redkina
Project title : 
Wide Bandwidth Wide Scan Antenna Array

This project explores the possibility to utilize a multi-mode antenna element in an array environment in order to electronically scan the beam over the entire hemisphere. This project involves the optimization of the antenna geometry and mode excitation coefficients through a combination of array signal processing techniques and electromagnetic simulations, over both frequency and scan angle. Finally, a sparse antenna array configuration study will be performed to obtain a final design.

Project period: 2014