Gerald Artner Research Amateur Other Facebook
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Technische Universität Wien Institute of Telecommunications Google Scholar IEEE Xplore Open Researcher and Contributor ID Research Gate

Chassis Antenna Cavity Conical Monopole Antenna on Circular CFRP Ground Plane Measurements of Interference Alignment
Chassis Antenna Cavity Carbon Fiber Antennas Interference Alignment
LDS Dipole Antenna Vehicular Communications Vienna young Scientists Symposium
Laser Direct Structuring Vehicular Communications Vienna young Scientists Symposium

Chassis Antenna Cavity
Sketch of Car With Chassis Antenna Cavity and Patterns Towards Front/Back and Left/Right Automotive Pattern Reconfigurable Antennas Concealed in a Chassis Cavity doi logo
G. Artner, J. Kowalewski, C.F. Mecklenbräuker and T. Zwick
International Symposium on Wireless Personal Multimedia Communications (WPMC), Yogyakarta, Indonesia, 2017.

Pattern-reconfigurable antennas for the 2.45GHz ISM band are concealed inside a chassis antenna cavity. Three antennas are designed to reconfigure between near-optimum radiation patterns for urban scenarios by toggling between front/back and left/right radiation. The three antennas follow distinct design principles and have different gain switching capabilities. Antenna performance is evaluated based on gain pattern measurements. It is shown, that the antennas retain their reconfiguration functionality when they are placed in the chassis cavity beneath the vehicle's roof.

Carbon Fiber Reinforced Polymer Cavity for Vehicular Antennas TU Wien logo
G. Artner
Dissertation, Technische Universität Wien, Vienna, December, 2017.

Vehicles increasingly communicate with their surrounding environment. They are no longer mere receptors of radio broadcasts, but actively exchange information with their surroundings. These communicative vehicles will radically change our view on transportation. They enable cooperative driving and are used as mobile access nodes for telecommunication networks - no longer just moving combustion engines. Extended radio frequency hardware is the technical basis for this increase in wireless vehicular communication. The critical part of the communication system are the antennas, as they have to be placed outside the vehicles hull and therefore become interdependent with vehicle design. This dissertation examines the influence of carbon fiber reinforced polymer on vehicular antennas and the development of an antenna cavity for vehicles. Together these findings secure enough construction space for antennas in future light-weight constructed vehicles.

Electric cars are increasingly constructed with chassis made from Carbon Fiber Reinforced Polymer (CFRP). This requires the characterization of these materials for vehicular antennas. Material samples are measured inside rectangular waveguides and the material parameters are estimated with the Nicolson-Ross-Weir method. Measurement results show, that the electric conductivity of CFRP with twill-weave and CFRP with fiber shreds on the surface are approximately isotropic in the investigated frequency range around 6 GHz. This motivates the use of recycled CFRP. Sustainable materials are in this case also optimal for antenna applications. The transition from metal to CFRP chassis influences monopole antennas, which are currently widely used in automotive applications, as these antennas use chassis parts as ground plane. Both narrowband and wideband monopole antennas are measured on ground planes manufactured from different CFRP.

A cavity for vehicular antennas is designed, manufactured, measured and evaluated. The cavity is larger than currently used roof-mounted shark-fin antenna modules and can be manufactured as part of the chassis and hidden therein. As proof that the production of such a cavity is realizable for electric cars, a prototype is built from CFRP. To show feasibility for antennas, several antennas are measured and evaluated inside the cavity. Investigated antennas include a monopole antenna and an inverted-F antenna, both manufactured as laser-structured injection molded parts; a broadband conical monopole antenna and intelligent antennas with reconfigurable radiation patterns. Detailed measurement based evaluations of the antennas inside the cavity show that the cavity concept is feasible. Influences of the cavity on the functionality of the antennas inside are also analyzed by measurement. Strong influences on the antennas occur at frequencies in the high single-digit gigahertz range, where the cavity is electrically large.

Size Comparison of Shark-fin, Chassis Cavity and Base-Station Antenna The Communicative Vehicle: Multiple Antennas in a Chassis Antenna Cavity doi logo
G. Artner
IEEE Vehicular Technology Conference (VTC Fall), Toronto, Canada, 2017.

The number of antennas mounted on vehicles keeps growing. Antennas in hidden modules will replace or supplement antennas in shark-fin modules. Chassis antenna cavities were recently proposed as large antenna modules, which can be built, and concealed, inside the vehicle chassis. Recent results of multiple antennas inside a chassis antenna cavity are presented. An inverted-F antenna and a conical monopole antenna are compared, based on measurements performed in an anechoic chamber. Measurements suggest that the position of the antenna inside the cavity has a significant influence on the gain pattern. Further measurements of frequency sweeps are needed, but prior to that exchangeable cavity bases are required.

Conical Monopole Antenna in Antenna Cavity with Exchangeable Base Exchangeable Bases for Rapid Prototyping of Carbon Fiber Reinforced Polymer Antenna Cavities doi logo
G. Artner and C.F. Mecklenbräuker
IEEE-APS Topical Conference on Antennas and Propagation (APWC), Verona, Italy, 2017.

Chassis antenna cavities were recently introduced as large, hidden, antenna modules. Testing different antenna configurations inside the module would require cutting several holes into the cavity floor. Manufacturing of several prototypes is not feasible, especially for carbon-fiber reinforced polymer chassis; flexible solutions are desired. Exchangeable cavity bases for chassis antenna cavities are proposed, designed and manufactured. Antenna measurements show the feasibility of the concept.

Monopole Antenna in Antenna Cavity for the Roof End Vehicular Roof Antenna Cavity for Coverage at Low Elevation Angles doi logo
G. Artner, R. Langwieser and C.F. Mecklenbräuker
IEEE International Symposium on Antennas and Propagation (APS), San Diego, California, USA, 2017.

Chassis cavities have recently been proposed as a new mounting position for vehicular antennas. Cavities can be concealed and potentially offer more space for antennas than shark-fin modules mounted on top of the roof. An antenna cavity for the front or rear edge of the vehicle roof is designed, manufactured and measured for 5.9 GHz. The cavity offers increased radiation in the horizontal plane and to angles below horizon, compared to cavities located in the roof center.

Sketch of Car With Chassis Antenna Cavity and Patterns Towards Front/Back/Left/Right Pattern Reconfigurable Antenna With Four Directions Hidden in the Vehicle Roof doi logo
G. Artner, J. Kowalewski, C.F. Mecklenbräuker and T. Zwick
International Workshop on Antenna Technology (iWAT), Athens, Greece, 2017.

Chassis integrated antenna cavities offer ten times the space of conventional automotive roof mounted antenna modules and can be fully concealed beneath the roofline. A pattern reconfigurable antenna for 2.6 GHz LTE is measured inside an automotive chassis cavity. The antenna can be electrically reconfigured to radiate towards the front, back, left or right side of the vehicle. Measurement results show that the antenna retains this ability when being hidden beneath the roof, proving that it is possible and feasible to hide antennas utilizing pattern diversity inside chassis cavities.

Exemplary Location of the Chassis Antenna Cavity in the Car Roof Concealed CFRP Vehicle Chassis Antenna Cavity doi logo
G. Artner, R. Langwieser and C.F. Mecklenbräuker
IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1415 - 1418, 2017.

A concealed vehicular carbon fiber reinforced polymer (CFRP) cavity in the roof which contains antennas is proposed, prototyped and measured. Compared to state of the art roof mounted shark-fin modules this offers significantly more room for antennas and radio frequency hardware, thus enabling a smooth transition of vehicular connectivity towards 5G. Three antennas were prototyped and embedded in the cavity: Two laser direct structured (LDS) antennas (inverted-F antenna for 2 GHz, monopole for 5.9 GHz), as well as a broadband conical monopole antenna milled from brass that characterizes the feasible frequency range from 2 to 6 GHz by measurement. It is shown that near-omnidirectional radiation from the concealed automotive antenna cavity is achievable.

Dimensions of an Automotive CFRP Antenna Cavity Prototype Carbon Fiber Reinforced Polymer Integrated Antenna Module doi logo
G. Artner, R. Langwieser, R. Zemann and C.F. Mecklenbräuker
IEEE-APS Topical Conference on Antennas and Propagation (APWC), Cairns, Australia, 2016.

Rising demand for vehicular communication and cooperative movement have led to an increase of vehicle mounted antennas. A carbon fiber reinforced polymer cavity is presented, that can be integrated into the vehicle chassis. The concealed cavity is large enough to house the anticipated antennas for present and future vehicular communication. Influence of the cavity onto antennas is demonstrated with calibrated gain measurements on the example of a 5.9 GHz monopole antenna for intelligent transportation systems. The cavities impact on antenna performance is found to be much smaller than influences of the car itself.

Antennas With Carbon Fiber Reinforced Polymer (CFRP)
Measurement of twill-weave CFRP for millimeter-waves Angle-dependent reflectivity of twill-weave carbon fibre reinforced polymer for millimetre waves doi logo IET logo
G. Artner, E. Zöchmann, S. Pratschner, M. Lerch, M. Rupp, C. Mecklenbräuker
Electronics Letters, vol. 54, no. 6, pp. 359-361, 2018.

Twill-weave carbon fibre reinforced polymer is measured as reflector material for electromagnetic waves at 60 GHz. The reflectivity at millimetre wavelength shows a predominant direction, which coincides with the diagonal pattern of the twill's top layer. In the remaining directions the investigated 2/2 twill-weave composite's reflectivity is almost isotropic.

Measurements of CFRP Material Properties with NRW-Method Carbon Fiber Reinforced Polymer With Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance doi logo open access logo
G. Artner, P.K. Gentner, J. Nicolics and C.F. Mecklenbräuker
International Journal of Antennas and Propagation, Volume 2017, Article ID 6152651, 2017.

A carbon fiber reinforced polymer (CFRP) laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the frequency range of 4 to 6 GHz. The decrease in material anisotropy results in negligible influence on antennas. This is shown by measuring the proposed CFRP as ground plane material for both a narrowband wire monopole antenna for 5.9 GHz and an ultra-wideband conical monopole antenna for 1-10 GHz. For comparison, all measurements are repeated with a twill-weave CFRP.

Conical Monopole Antenna on Circular CFRP Ground Plane Carbon Fiber Reinforced Polymer as Antenna Ground Plane Material Up to 10 GHz doi logo
G. Artner, R. Langwieser and C.F. Mecklenbräuker
European Conference on Antennas and Propagation (EuCAP), Paris, France, 2017.

Carbon Fiber Reinforced Polymer (CFRP) or generally Carbon Fiber Composites (CFC) are increasingly utilized in lightweight construction. Large CFRP parts such as chassis or fuselages are utilized as antenna ground planes. However, radiation characteristics of antennas designed for metal ground planes change when mounted on anisotropic composites. In this paper the influences of CFRP ground planes on the radiation characteristics of antennas in the range from 1 - 10 GHz are investigated with measurements of conical monopole antennas. Measurements show that ground planes from unidirectional CFRP severely distort radiation patterns, while the influence of woven plies is small.

Automotive Shark-Fin Antenna Module on a CFRP Car Roof Performance of an Automotive Antenna Module on a Carbon-Fiber Composite Car Roof doi logo
G. Artner and R. Langwieser
European Conference on Antennas and Propagation (EuCAP), Davos, Switzerland, 2016.

The introduction of carbon-fiber composites in chassis production changed the materials in the vicinity of vehicular antennas. The two IEEE 802.11p antennas of an automotive antenna system are measured on a carbon-fiber roof and an aluminum sheet. Gain patterns are in good agreement, radiation efficiency on the carbon-fiber roof is about ten percentage points lower than on aluminum.

Monopole Antennas on Different CFRP Ground Planes Effect of Carbon-Fiber Composites as Ground Plane Material on Antenna Performance doi logo
G. Artner, R. Langwieser, G. Lasser and C.F. Mecklenbräuker
IEEE-APS Topical Conference on Antennas and Propagation (APWC), Palm Beach, Aruba, 2014.

The impact of carbon fiber composites (CFC) as a ground plane material on antenna performance is investigated. CFC are lighweight materials that, due to their high mechanical durability, are increasingly used as chassis material for cars. Their electrical characteristics are anisotropic and dependent on the manufactured structure, which is expected to influence the radiation pattern. Simple monopole antennas for 2.45 GHz (ISM) and 5.9 GHz (ITS G5) are mounted to circular ground planes made of three diferent CFC and aluminum sheets. The influence on antenna performance is investigated with calibrated gain, return loss and the radiation pattern measurements.

Interference Alignment
IA Testbed Receiver with 4 Antennas Inside Laptop Measuring the Impact of Outdated Channel State Information in Interference Alignment Techniques doi logo
G. Artner, M. Mayer, M. Guillaud and M. Rupp
IEEE 8th Sensor Array and Multichannel Signal Processing Workshop (SAM), La Coruna, Spain, 2014.

Interference alignment has been proposed as a transmission technique to cancel the interference for the K-user interference channel at high signal-to-noise ratio. In the case of multiple-input multiple-output (MIMO)-transmission the interference can be aligned in a subspace of the receiver antennas. In this work we investigate the impact of outdated channel state information (CSI) due to temporal channel variations on the performance of interference alignment. Experimental transmissions of real-time precoded signals from an indoor and outdoor MIMO testbed exhibit performance degradation due to outdated CSI. Furthermore, a model is proposed and evaluated that describes the temporal channel fluctuations based on these measurements.

Measurements of IA, theory vs. reality Measurement and Modelling of Interference Alignment Impairments doi logo
M. Mayer, M. Guillaud, G. Artner and M. Rupp
IEEE 8th Sensor Array and Multichannel Signal Processing Workshop (SAM), La Coruna, Spain, 2014.

Interference alignment is a linear precoding technique that eliminates interference in the K-user interference channel. We present measurement results and identify the performance limiting factors that occur under real conditions. In our setup, we found the main causes of impairment to be outdated channel state information in varying channels, thermal noise at the receiver and transmit impairments. We propose a simplistic channel model that is capable of capturing these effects and allows to investigate their impact on the achievable rate.

IA with 4 Transmit and Receive Antennas (Allowing for 2 Data Streams) Receiver Location Sensitivity of Interference Alignment TU Wien logo
G. Artner
Diplomarbeit (Master's Thesis), Technische Universität Wien, Institute of Telecommunications, Vienna, September 2013.

Modern mobile communication systems are designed based on the cellular principle. The efficiency of such systems is primarily limited by interference from neighboring base stations at the cell edge. In recent years various schemes have been developed to minimize interference through base station cooperation. One such promising scheme is interference alignment (IA). Although theoretically well understood, measurement based evaluations are rare.
Interference alignment (IA) relinquishes half of the available data streams of a mobile connection to align the interference in their subspace and promises an interference free transmission on the remaining data streams. IA uses linear transmit and receive filters and requires global knowledge of the communication channels to calculate these filters. Furthermore IA requires various assumptions regarding the communication channels and the communication network. An important assumption is that the radio channels remain constant from their measurement on to the transmission of the data.
This thesis shows in a scientific, on modern communication systems based, measurement environment that practical channels allow the application of IA and presents measurements that show the impact of changing channels on the efficiency. First the theoretical basics and measurement methods of characteristic figures are summarized. Then the used measurement system, the Vienna MIMO testbed (VMTB), is specified. Differences to a commercial system are clarified and the developed software explained. Additionally the performance of IA under changing channels is quantitatively investigated with the use of mutual information.

Measurements with 3 Transmitters and 1 Receiver Measurement Based Evaluation of Interference Alignment on the Vienna MIMO Testbed IEEE Xplore logo
M. Mayer, G. Artner, G. Hannak, M. Lerch and M. Guillaud
International Symposium on Wireless Communication Systems (ISWCS), Ilmenau, Germany, 2013.

Interference Alignment (IA) is a linear precoding scheme for the K-user interference channel with high signal to noise ratio. Ideally, interference is completely suppressed and each user is able to achieve half of the single-user multiple-input multiple-output (MIMO) degrees of freedom. We use the Vienna MIMO testbed to evaluate the feasibility of IA in realtime, in a heterogeneous outdoor to indoor and indoor to indoor scenario representative of an urban scenario. We evaluate the accuracy of alignment and provide benchmarks for typical delays in such a setup.

Laser Direct Structuring
LDS dipole antenna A MID Dipole Antenna in LDS Technology doi logo
G. Artner, R. Langwieser and C.F. Mecklenbräuker
24th Telecommunications Forum (TELFOR), Belgrade, Serbia, 2016.

Molded interconnect devices (MID) allow the realization of electronic circuits on injection molded thermoplastics. MID antennas can be manufactured as part of device casings without the need for additional printed circuit boards or attachment of antennas printed on foil. Baluns, matching networks, amplifiers and connectors can be placed on the polymer in the vicinity of the antenna. A MID dipole antenna for 1 GHz is designed, manufactured and measured. A prototype of the antenna is built with laser direct structuring (LDS) on a Xantar LDS 3720 substrate. Measured return loss and calibrated gain patterns are compared to simulation results.

Laser Direct Structured Monopole Antenna on Quadratic CFRP Ground Plane Material Induced Changes of Antenna Performance in Vehicular Applications doi logo
G. Artner, R. Langwieser and C.F. Mecklenbräuker
IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS), Tel-Aviv, Israel, 2015.

Recent advancements in production materials for cars replace well-known ground plane materials for vehicular antennas. Carbon-fiber composites (CFC's) replace steel as chassis material, which leads to reduced radiation efficiency. As the production processes of shark-fin antenna modules shift towards laser direct structuring (LDS), it is investigated, if antenna efficiency can be increased by the introduction of a LDS ground plane. Differences in antenna performance are presented on the example of simple LDS and wire monopole-antennas for 5.9 GHz (IEEE 802.11p, ITS G5). Gain, efficiency, return loss and the radiation patterns of an LDS design, a CFC and an aluminum ground plane are compared.

Vehicular Communications
Millimeter Wave Car-to-Car Communication Measured Delay and Doppler Profiles of Overtaking Vehicles at 60 GHz TU Wien logo
E. Zöchmann, C.F. Mecklenbräuker, M. Lerch, S. Pratschner, M. Hofer, D. Löschenbrand, J. Blumenstein, S. Sangodoyin, G. Artner, S. Caban, T. Zemen, A. Prokeš, M. Rupp and A.F. Molisch
accepted at European Conference on Antennas and Propagation (EuCAP), London, England, 2018.

We report results from real-world millimetre wave vehicle-to-vehicle channel measurements carried out in an urban street environment, down-town Vienna, Austria. Channel measurements have been acquired with a time-domain channel sounder in the frequency band 59.75-60.25 GHz with a frequency resolution of approximately 5 MHz. We estimate the local scattering function for sequential stationarity regions in time. A multitaper estimator is used to precisely define Doppler and delay resolutions. Estimates for delay and Doppler profiles are evaluated from the local scattering function for several overtaking vehicles at a variety of speeds and for different types of vehicles. The results show that passenger cars are associated with a single Doppler trajectory, whereas larger vehicles, such as trucks, show up in the data with multiple Doppler trajectories.

LTE Vehicular Measurement Setup Measurement and Analysis of LTE Coverage for Vehicular Use Cases in Live Networks doi logo
T. Berisha, G. Artner, B. Krasniqi, B. Duriqi, M. Muçaj, S. Berisha, P. Svoboda and C.F. Mecklenbräuker
IEEE-APS Topical Conference on Antennas and Propagation (APWC), Verona, Italy, 2017.

We conducted drive test measurements in a live LTE 1800 MHz network to evaluate mobile network performance of User Equipments (UEs) located inside and outside a pickup truck. The measurement campaing is performed in Kosovo, starting from Prishtina to the south-western Albanian border. Knowledge of base station locations and cell load during the measurements is made available from the service provider. This is crucial to determine whether the bit rate is limited by network availability, cell load, or propagation effects. To provide reliable in-vehicle coverage, it is necessary to determine the penetration loss. In this paper, we present the first results and show that the penetration loss varies by up to 10.58 dB.

Vienna young Scientists Symposium (VSS)
TU and VSS logos Vienna young Scientists Symposium (VSS)
The VSS is a national Austrian conference for young researchers. I had the please to participate in 2015 and 2016 and the honor to chair the conference in 2017.

Proceedings 2015
Proceedings 2016
Proceedings 2017

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