Search

Your search keyword '"Herben, M. H. A. J."' showing total 42 results
Start Over Author "Herben, M. H. A. J."
42 results on '"Herben, M. H. A. J."'

5. Electromagnetic field strength prediction in an urban environment: A useful tool for the planning of LMSS

Author

Vandooren, G. A. J, Herben, M. H. A. J, Brussaard, G, Sforza, M, and Poiaresbaptista, J. P. V

Subjects
Communications And Radar
Abstract

A model for the prediction of the electromagnetic field strength in an urban environment is presented. The ray model, that is based on the Uniform Theory of Diffraction (UTD), includes effects of the non-perfect conductivity of the obstacles and their surface roughness. The urban environment is transformed into a list of standardized obstacles that have various shapes and material properties. The model is capable of accurately predicting the field strength in the urban environment by calculating different types of wave contributions such as reflected, edge and corner diffracted waves, and combinations thereof. Also, antenna weight functions are introduced to simulate the spatial filtering by the mobile antenna. Communication channel parameters such as signal fading, time delay profiles, Doppler shifts and delay-Doppler spectra can be derived from the ray-tracing procedure using post-processing routines. The model has been tested against results from scaled measurements at 50 GHz and proves to be accurate.

Published
1993

7. Fundamental challenges for wideband antenna elements in focal-plane arrays

Author

Aleksei Dubok, Al-Rawi, A., Herben, M. H. A. J., Adrianus Bernardus Smolders, Electromagnetics, and Center for Wireless Technology Eindhoven

Abstract

This paper discusses the main design challenges of wideband antenna elements which can be used in focal-plane arrays. A novel electrically-small wideband antenna is presented. It is based on a bow-tie antenna. The proposed antenna shows excellent input matching properties over a frequency band of more than one octave and nearly reaches the theoretical Chu-Harrington limit. It is shown that the centre element of a five-element feed array, operating at a centre frequency of 30 GHz, realizes an input matching bandwidth of 24.4 GHz.

Published
2015

8. Point-to-point radio link variation at E-band and its effect on antenna design

Author

Al-Rawi, A., Aleksei Dubok, Herben, M. H. A. J., Adrianus Bernardus Smolders, Electromagnetics, and Center for Wireless Technology Eindhoven

Abstract

Radio propagation will strongly influence the design of the antenna and front-end components of E-band point-to-point communication systems. Based on the ITU rain model, the rain attenuation is estimated in a statistical sense and it is concluded that for backhaul links of 1–10 km, antennas with a gain of 49.5 dBi are required. Moreover, depolarization can be a limiting factor for backhaul systems that are employing orthogonal polarization in order to improve capacity. Antenna mast movement becomes a relevant problem due to the narrow beamwidth of the high gain antennas, which is around 0.7◦ . We propose to implement a focal plane array as feed for the parabolic reflector antenna. This is to tackle the mast movement by electronic beam steering and to increase EIRP by increasing the number of active antenna elements, and to assist the mechanical alignment during installation.

Published
2015

26. Measurements corner: Causes of discrepancies between measurements and EM simulations of millimeter-wave antennas.

Author

Fischer, Brian E., LaHaie, Ivan J., Huang, M. D., Herben, M. H. A. J., Reniers, A. C. F., and Smulders, P. F. M.

Subjects
PERMITTIVITY measurement, MILLIMETER wave antenna arrays, POLYMER liquid crystals, MICROSTRIP resonators, MEASUREMENT errors
Abstract

This article describes the possible factors that can introduce discrepancies between measurements and three-dimensional EM simulations of millimeter-wave (mm-wave) antennas. The effects of the choice of the simulation solver, the relative permittivity and the homogeneity of the substrate material, the manufacturing tolerance, and the measurement errors are discussed. It is concluded that a fair comparison between measurements and simulations of mm-wave antennas can only be made if all these possible causes of discrepancies are taken into account. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
View/download PDF

27. Modular Antenna Array Concept for Millimeter-wave Beam-steering Applications.

Author

Johannsen, U., Kazim, M. I., Smolders, A. B., and Herben, M. H. A. J.

Subjects
ANTENNA arrays, HOUSEHOLD electronics, BANDWIDTHS, COMPLEMENTARY metal oxide semiconductors, WIRELESS communications, WAVELENGTHS
Abstract

Steerable antenna arrays are of particular importance for consumer electronics applications in the millimeter-wave band. However, the exact array size depends on the specific application scenario. Therefore, a modular array concept is proposed in this paper that meets the cost requirements of the consumer electronics market. Moreover, since circular polarization is desired due to the line-of-sight nature of the communication channel at those frequencies, special attention is placed on the construction of circularly-polarized antenna arrays. Finally, a deflector design is proposed that allows to extend the scan-range of the proposed modular antenna array. [ABSTRACT FROM AUTHOR]

Published
2013

37. A Review and Comparison of Some Asymptotic Techniques for Calculating the Wide-angle Radiation Pattern of Paraboloid Reflector Antennas

Author

de Maagt, P. J. I., Chen, J., and Herben, M. H. A. J.

Abstract

The paper starts with a review of calculation methods for determining the complete far-field radiation patterns of reflector antennas. Subsequently, a direct comparison is made between PO, APO, CAPO, GTD, UTD and EEC methods by applying all of these techniques to one and the same reflector antenna configuration. It is shown that both UTD, including surface-diffracted rays, and CAPO is satisfactory for calculating the scattered field from reflector antennas in wide-angle regions (away from the antenna axis). The correct results in both forward- and rear-axial region can be obtained with PO and EEC, respectively. Finally, special attention is paid to the transition angle between EEC and UTD.

Published
1992
Full Text
View/download PDF

38. Evaporation derived from optical and radio-wave scintillation

Author

Kohsiek, W. and Herben, M. H. A. J.

Abstract

The determination of the evaporation from scintillation measurements at several wavelengths is discussed. The refractive-index structure parameter Cn2 derived from the observed amplitude scintillation on a 30-GHz radio link is compared to a spot measurement of this quantity at a much lower height than that of the radio link. After free convection height scaling, a difference of a factor of 3 is found. This factor is discussed. A calculation of the evaporation from the observed radio-wave scintillation yields good agreement with calculations based on the Priestley-Taylor formula.

Published
1983

39. MULTIFREQUENCY ANTENNA SYSTEM FOR PROPAGATION EXPERIMENTS AT 12.5, 20, AND 30 GHZ.

Author

Herben, M. H. A. J., De Maagt, P. J. I., Van de Goor, W. A., and Casper, A. C. A.

Subjects
*REFLECTOR antennas, *APERTURE antennas, *SATELLITE dish antennas, *ANTENNAS (Electronics), *HORN antennas
Abstract

A multifrequency antenna system for future propagation experiments at 12.5, 20, and 30 GHz with the Olympics satellite, is described. This antenna system consists of a 5.5 m Cassegrain reflector antenna and a multifrequency feed system. [ABSTRACT FROM AUTHOR]

Published
1989
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results