Dr. Rob Maaskant

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 20032010 he was employed as a Researcher at the Netherlands Institute of Radio Astronomy (ASTRON), The Netherlands, and from 20102012 as a postdoctoral researcher at the Chalmers University of
Technology, Sweden, for which he received a MarieCurie (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
integralequation 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 mmwave 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.efermat.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
email: 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/aboutchalmers/vacancies/Pages/default.aspx ; https://www.tue.nl/en/university/workingattue/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 16 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 2year postdoctoral fellowships. Should you be
interested in applying please get in touch and we can assist you. More information: postdoc funding Jan 2018.pdf
 Visiting faculty:
If you are interested in visiting the Department of Electrical Engineering
for a shortterm research stay, we can offer limited financial support.
Feel free to get in touch for further information.
Projects

VIDI project Packaging and Integration of mmWave Antennas and ChipsThe research into mmwave technology is being pushed by a worldwide need to develop next generation wireless systems. These systems are small in size, offer large frequency bandwidths, are costeffective and allow for high degree of electronic system integration. The current integration and packaging concepts of antennas and electronics are plagued by crosstalk effects and cavity resonance issues and a limited overall performance. Ultra lowloss metalonly antennas are preferred, but these cannot be connected directly to integrated circuits. A breakthrough in the mmwave domain is urgently needed to overcome these problems. Innovative system integration concepts are proposed that are based on the hybridization of circuit and quasioptical 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 lowloss metamaterial technologies has now enabled us to allow for a crosstalk and resonancefree packaging of circuits and antennas. Inhouse specialized numerical techniques will be used to develop new and fast optimization approaches for electrically large antenna arrays packaged with frontend electronics. Several prototypes will be designed to showcase the newly proposed system integration concepts and the impact thereof for many mmwave applications and future research into submm 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 MattersKammerer (TU/e) Promotor 3 : Prof. Marianna Ivashina (Chalmers) Project period: 2017  2021 

The SILIKA Training and Research Program
Silicon Based Kaband massive MIMO antenna systems for new telecommunication serviceshttp://silikaproject.eu/
The continuously growing need for higher datarates and,
therefore, more signal bandwidth in wireless communications,
requires the use of multiantenna base stations employing the
recently introduced massive MultipleInputMultipleOutput (MIMO)
concept and operating at millimeterwave frequencies, e.g. 30
GHz. However, the implementation of such complex antenna systems into
highlyintegrated, energy and costeffective solutions is very
challenging. Therefore, we propose an innovative antenna system
concept utilizing silicon semiconductor electronics that can generate
or receive at millimeterwave 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 (mmwave) frequencies utilizing highlyintegrated and
costeffective silicon (Bi) CMOS technologies. These antenna systems
will rely on the use of multiantenna massive MIMO concepts in which the
number of individual antenna elements in the base station is much
larger than the number of users. In stateoftheart phased arrays, only
a limited number of identical antenna beams are used, usually operating
in a single frequency band. Multiantenna massive MIMO systems,
however, can generate multiple beams, each with different shape
operating at different frequencies, using polarization agility and
adaptive waveforms.
Multielement antenna systems are expected to increase the energy
efficiency of future base stations, while achieving high data rates with
indoors and outdoor coverage both for lineofsight and
nonlineofsight propagation conditions, by sending out many
independent data streams to simultaneously serve many users. The
proposed design methods in SILIKA aim at synthesizing energyefficient
multibeam 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 largescale, beamsteering 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 frontend electronics in the optimization of iAAs
 Investigate novel antenna array integration concepts and test their potential
Project period: 2017  2020 

Ph.D. Student : Alhassan Aljarosha (Vidi project) Project title : Packaging and Integration of mmWave 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 mmWave antenna and waveguide structures. He works in close collaboration with PhD student Piyush Kaul, see below, to facilitate a contactless transition from waveguide to Siliconbased integrated circuits via quasioptical techniques.
Project period: 2017  2020 

Ph.D. Student : Piyush Kaul (Vidi project) Project title : Packaging and Integration of mmWave Antennas and Chips
Please see the above Vidi project description for more information . Piyush is an integrated circuit (IC) specialist
focusing primarily on the mmWave power generation of Siliconbased MMICs employing both series and parallel on and offchip power combining techniques. He works in close collaboration with PhD student
Alhassan Aljarosha, see above, to facilitate a contactless transition from
waveguide to Siliconbased integrated circuits via quasioptical
techniques.
Project period: 2017  2020 

Ph.D. Student : WanChun Liao (ChaseOn project) Project title : Integrated Array Antennas
The goal is to develop a design flow to optimally impedancematch a power amplifying Integrated Circuit (GaN IC) directly to an array antenna element, thereby avoiding relatively lossy 50Ohm matching networks while potentially increasing the frequency bandwidth at the same time. This requires a cooptimization approach of both the IC and the antenna, each having their own mutuallydependent design constraints. We will consider linearity, radiated output power (EIRP), power efficiency, cooling aspects, and array mutual coupling effects. The project focuses on 1540 GHz applications. Yet, WanChun 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 SystemLevel 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 systemlevel approach to characterize MIMO transceiver base station antennas in two extreme propagation scenarios of a 'reallife' channel, i.e., the socalled edge reference environments: Rich Isotropic Multipath and Random LineofSight. Experimental systemlevel validation will be done using a systemlevel testbed using a quadmode 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 mmwave power transmitters using emerging lowloss dielectricfree metamaterial technologies for the integration and packaging of array antennas and electronics to mitigate the problems of conventional approaches causing crosstalk effects and cavity resonances. We will employ these novel technologies to design a mmwave distributed siliconbased power grid amplifier with highgain performance. This design process will include the following steps: (i) conceptual studies of distributed silicon amplifiers to decide on most promising architectures; (ii) semi analyticalnumerical simulations to select the best topology that is suited for large scale deployment of metalonly 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 subprojects 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 InvertedF Antenna
This project
explores the possibilities of designing a compact and lowcost planar invertedF antenna for wireless communication applications. The design supports the direct integration with electronics (see the above PhD project WanChun 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) domaindecompositionbased 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 sidelobe level is imposed as a constraint in the optimization approach; (vi) multiple element types and multimode 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 DTUSpace (Denmark).
The
challenge of designing PAFs for radio telescopes is to account for the effects of
array element mutual coupling and feedreflector 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 methodofmoments (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 antennaamplifierbeamformer 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 mmwave/subTHz frequencies are among the possibilities.


M.Sc. Student : Waqar Ali Shah Project title : MillimeterWave Spatial Power Splitting and Combining for use in GapWaveguideIntegrated Grid Amplifiers and Antenna Arrays
Conventional power splitters and combiners employing substratebased transmission lines suffer from both conductor and dielectric losses, in particular at mmwave 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 airdielectrics. This will be done in a planar fashion and be packaged at the same time using gapwaveguide 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 reflectorwallbased backtoback gap waveguide structure. This work is important because it represents a lowloss power splitting and combining solution for mmwave systems. It also forms the basis for a mmwave grid amplifier in gap waveguide technology and in the long run  at submm wavelength frequencies  it becomes a costeffective solution as an allintegrated system on chip. Moreover, a lowloss 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 submm 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 mmWave Contactless Microstrip Line to Groove Gap Waveguide Transition Suited For MMIC Integration
Realizing a lowloss transition of the electromagnetic fields from a metalonly waveguide structure to a transmissionline on a chip is a major challenge at mmwave frequencies. Such transitions typically suffer from Ohmic losses, impedance mismatch effects, a limited frequency bandwidth, and spurious radiation of bondwires and crosstalk 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 resonancefree packaging solution of integrated circuits. The animation shows how the field is guided through the ridge waveguide structure. Note the guided wavesonchip 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 Wband. It is foreseen that this technology is going to lead to a breakthrough in the mm and submm wave frequency bands. At submm wave frequencies it is envisioned that the entire technology can be integrated in a costeffective manner onto a physically small (but electrically large) chip through a micromachining process. Such technologies will enable lowloss mmwave 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 twofold: (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 overtheair (OTA) applications. A typical scattering
environment is emulated and characterized using inhouse 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 DirectionDependent 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 physicsbased 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 offaxis 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 degreesoffreedom in the beamformer can be used for beamforming purposes other than for beamdistortion correction.


Post. Doc. : Dr. Andre Young
Project title : DirectionDependent Gain Calibration Using the CBFP Method
(Stellenbosch University, South Africa, group of Prof. David Davidson)
Further development and practical application of the newly proposed physicsbased 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 highresolution basis functions for the accurate modeling of the volume equivalent currents. These basis functions are fractions of wavelengths in size and therefore called microdomain 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
(offdiagonal 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 filltime due to an increased
number of basis functions. The MultiLevel 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 incore, for
multiple righthand 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 complexshaped 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 xpolarized plane wave traveling along z. 12507
microbasis 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 socalled gap waveguides are novel
lowloss lowcost nondispersive transmission lines that are wellsuited
for various future highfrequency applications. At this moment, however,
the numerical analysis using commercially available CEM software tools
is a very timeconsuming  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
gapwaveguide 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
methodofmoments 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 gapwaveguide 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 runtime. 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 wellknown 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 : MixedMode 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 midfrequency 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 commonmodes that propagate between them. In order to quantify the effect both propagation modes have on the system sensitivity a mixedmode, multiport 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 fieldofview coverage pattern forms an important part of the project.
Project period: 2011  2014


Ph.D. Student : Theunis Beukman Project title : Differential QuadRidged 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 lownoise amplifiers (dLNAs) and singlepixel feeds proposed for the 110 GHz band of the Square Kilometre Array (SKA) radio telescope. A new type of reflector antenna feed has been proposed: a differentially excited quadridged horn antenna, providing a more constant beamwidth over frequency as well as demonstrates an improved symmetrical beam properties as opposed to more conventional coaxialprobeexcited horn feeds.
The project involves a detailed theoretical analysis of the modal content of the fields in the horn antenna, amplifierantenna 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 inhouse numerical software tool (CAESAR) is used for the electromagnetic array design. It has been developed specifically for analyzing large antenna arrays in a timeefficient manner. It also interfaces with our inhouse 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 multimode 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


