Zobrazeno 1 - 10
of 195
pro vyhledávání: '"V, Schejbal"'
Autor:
V. Schejbal, V. Zavodny
Publikováno v:
Radioengineering, Vol 26, Iss 4, Pp 972-978 (2017)
This work analyzes the electromagnetic wave propagation above uneven ground, including the troposphere, using physical optics calculation. The new results of numerical simulations using physical optics are presented for the antenna far-field measurem
Externí odkaz:
https://doaj.org/article/ff51ab49ae284686a52989b2b68bcfc0
Publikováno v:
Radioengineering, Vol 24, Iss 4, Pp 892-897 (2015)
Measurements of test antennas are performed on antenna ranges. The operated microwave far-field outdoor range was built-up in 1970’s and therefore it was not appropriate for the today measurements. Thus, it was decided to perform the complete recon
Externí odkaz:
https://doaj.org/article/369db0f2bb8749899a392f078b4765b2
Publikováno v:
Radioengineering, Vol 21, Iss 1, Pp 471-477 (2012)
Various methods for analyses of scattering are mentioned and new approximate relationships are derived. Experimental results for thin wire and several numerical simulations of forward scattering using approximate estimations, physical optics and exac
Externí odkaz:
https://doaj.org/article/f1c7054ec0c445f68fc80c1237757123
Autor:
V. Schejbal, J. Pidanic
Publikováno v:
Radioengineering, Vol 19, Iss 4, Pp 639-644 (2010)
The broadband approximations for shaped-beam doubly curved reflector antennas with primary feed (rectangular horn) producing uniform amplitude and phase aperture distribution are derived and analyzed. They are very valuable for electromagnetic compat
Externí odkaz:
https://doaj.org/article/80267d22914d47b7813149c71218f749
Publikováno v:
Radioengineering, Vol 19, Iss 2, Pp 237-241 (2010)
This study is focused on the experimental research of the atmosphere impact on FSO link attenuation. Experiment is performed on a mountain observatory Milesovka of severe weather conditions. The empirical relationships on 830 nm only between FSO atte
Externí odkaz:
https://doaj.org/article/2827449fed48413a83ea745fb398fb9b
Publikováno v:
Radioengineering, Vol 18, Iss 4, Pp 561-566 (2009)
Synthesized-reference-wave holographic techniques offer relatively simple and cost-effective measurement of antenna radiation characteristics and reconstruction of complex aperture fields using near-field intensity-pattern measurement. These methods
Externí odkaz:
https://doaj.org/article/59a37ad725b34bf18c556b7050e45bb5
Autor:
V. Schejbal
Publikováno v:
Radioengineering, Vol 18, Iss 1, Pp 18-22 (2009)
An improved analysis of propagation over irregular terrain using physical optics approximation of vector problem is presented. It offers more reliable numerical simulations for low altitude propagation and diffraction field zone without any auxiliary
Externí odkaz:
https://doaj.org/article/3e4d725062274242919cbe2558e28988
Publikováno v:
Radioengineering, Vol 17, Iss 3, Pp 38-41 (2008)
A simple formula of approximate gain estimation is verified for the doubly curved reflector antenna. Numerical simulations using physical optics and experimental results of the shaped-beam doubly curved reflector antenna are compared with the simple
Externí odkaz:
https://doaj.org/article/67d1b66550b24ee88b5218f1ce41620e
Autor:
V. Schejbal, P. Bezousek
Publikováno v:
Radioengineering, Vol 17, Iss 3, Pp 53-59 (2008)
Radar systems, based on bistatic radar concept attracted a substantial attention in the recent years. Passive coherent location systems using "transmitters of opportunity" like radio or TV broadcasters, GSM base stations, satellite communication and
Externí odkaz:
https://doaj.org/article/40fc0fa84b8742c1810aeccf75663c2c
Publikováno v:
Radioengineering, Vol 15, Iss 4, Pp 52-57 (2006)
The UWB (ultra wide band) radar output signals can be substantially affected due to electromagnetic wave propagation through obstacles (such as walls) and multipath effects, too. Multipath effects are analyzed and simulated numerically for various ca
Externí odkaz:
https://doaj.org/article/5400c2ada42d433d81a13196acbc3bb6