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Improving Communication Channels
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Chassis Antenna Cavity
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Carbon Fiber Antennas
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Interference Alignment
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Laser Direct Structuring
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Teaching
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Numismatics
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Vehicular Communications
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Vienna young Scientists Symposium
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Improving Communication Channels
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Improving Mobile Communications with Antennas that Map the Channel and Move to Local Maxima
G. Artner
Microwave and Optical Technology Letters, pp. 1-7, 2023.
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A technique is proposed that improves wireless communication channels in fading environments.
The device creates a map of channel measurements.
The device then moves its antenna to positions of the previously measured maximum within its reach.
Proof-of-concept measurements were performed for smartphone-sized devices in an office environment.
A quarter-wavelength monopole antenna for the 2.4 GHz frequency band successfully kept the channel at local maxima.
The results show that small antenna movements over half of a wavelength are sufficient to keep the channel in local maxima, to avoid deep fading notches, and to improve channels over state-of-the-art antennas that move with their devices.
A channel model for the wireless communication channel of mobile devices with channel maximum antennas is proposed based on the measurement results.
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Chassis Antenna Cavity
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Electronically Steerable Parasitic Array Radiator Flush-Mounted for Automotive LTE
G. Artner, J. Kowalewski, J. Atuegwu, C.F. Mecklenbräuker and T. Zwick
European Conference on Antennas and Propagation (EuCAP), Krakow, Poland, 2019.
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A pattern reconfigurable antenna for 2.6 GHz LTE is flush-mounted in a chassis antenna cavity.
The driven element is a top-loaded monopole, that is steered based on the electronically steerable parasitic array radiator (ESPAR) principle.
The radiation pattern can be configured in 45 degree steps, e.g. front, diagonal front-right, right, etc.
The cavity prototype is made from carbon fiber reinforced polymer and includes a chassis mockup.
Antenna performance is evaluated based on measured gain patterns, which show that the antenna retains its reconfiguration capabilities when it is flush-mounted.
Further, a parametric measurement study with regards to antenna height inside the cavity is performed to investigate the option of mounting an electronics module underneath the antenna.
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Conformal Automotive Roof-Top Antenna Cavity With Increased Coverage to Vulnerable Road Users
G. Artner, W. Kotterman, G. Del Galdo and M.A. Hein
IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 12, pp. 2399-2403, 2018.
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Cooperatively driving cars benefit from increased coverage towards driving direction for communication with vulnerable road users.
Antenna cavities were designed, prototyped and measured for integration into car roofs above the windshield.
Two different antenna cavities were investigated.
First, an antenna cavity made from carbon fiber reinforced polymer was measured without a vehicle, to obtain general results without model specific influence.
Second, a metal cavity was built into the roof of a sedan type passenger car to include the marked effects of the car body and provide a proof of performance.
Gain patterns were measured in anechoic chambers.
Results show that the antenna structure and mounting position are suitable for omnidirectional radiation with increased radiation towards low elevation angles in driving direction.
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Simulation Model for Chassis Antenna Cavities Made from Carbon Fiber Reinforced Polymer
G. Artner, P.K. Gentner, R. Langwieser and C.F. Mecklenbräuker
European Conference on Antennas and Propagation (EuCAP), London, United Kingdom, 2018.
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Cavities built into the vehicle chassis have recently emerged as receptacle for hidden antennas.
In the automotive sector they potentially replace the roof mounted shark-fin antenna modules.
Simulation models for chassis antenna cavities are critical, because they must both accurately predict antenna performance, while staying computationally reasonable.
Moreover, if the chassis of electric cars, airplanes and boats are built with carbon fiber reinforced polymer, then a model for the composite laminate is required.
In this paper a simple simulation model for chassis antenna cavities is developed.
The carbon fiber composite material is modeled as a linear, homogeneous and isotropic conductor, and several cavity geometry details are omitted.
Simulation results are in good agreement with measurements in the frequency band at 5.9 GHz for intelligent transport systems.
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Carbon Fiber Reinforced Polymer Cavity for Vehicular Antennas
G. Artner
Dissertation, Technische Universität Wien, Vienna, December, 2017.
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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.
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Antennas With Carbon Fiber Reinforced Polymer (CFRP)
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Carbon Fiber Reinforced Polymer with Isotropic 60 GHz Reflectivity
E. Zöchmann, G. Artner, S. Pratschner, M. Lerch, C.F. Mecklenbräuker and M. Rupp
Progress In Electromagnetics Research M, vol. 67, pp. 1-8, 2018.
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Carbon fiber reinforced polymer (CFRP) is measured as reflector material for millimeter waves at 60 GHz.
Reflectivity is measured to characterize material anisotropy in a mono-static setup.
Disc shaped material samples are rotated in steps of one degree.
Four commonly employed CFRP are investigated: unidirectional fibers, plain-weave, twill-weave and fiber shreds.
Results show that the unidirectional CFRP and twill-weave CFRP are anisotropic, while the remaining materials are isotropic within measurement accuracy.
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Carbon Fiber Reinforced Polymer With Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance
G. Artner, P.K. Gentner, J. Nicolics and C.F. Mecklenbräuker
International Journal of Antennas and Propagation, Volume 2017, Article ID 6152651, 2017.
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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.
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Interference Alignment
Laser Direct Structuring
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Material Induced Changes of Antenna Performance in Vehicular Applications
G. Artner, R. Langwieser and C.F. Mecklenbräuker
IEEE International Conference on Microwaves, Communications, Antennas and Electronic Systems (COMCAS), Tel-Aviv, Israel, 2015.
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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.
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Teaching
Numismatics
Vehicular Communications
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Measured Delay and Doppler Profiles of Overtaking Vehicles at 60 GHz
E. Zöchmann, C.F. Mecklenbräuker, M. Lerch, S. Pratschner, M. Hofer, D. Löschenbrand, J. Blumenstein, S. Sangodoyin, G. Artner, S. Caban, T. Zemen, A. Proke, M. Rupp and A.F. Molisch
European Conference on Antennas and Propagation (EuCAP), London, United Kingdom, 2018.
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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.
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Measurement and Analysis of LTE Coverage for Vehicular Use Cases in Live Networks
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.
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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.
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Vienna young Scientists Symposium (VSS)
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