Results 91 to 100 of about 4,061 (210)

Multifrequency VLBI Observations of the Broad Absorption Line Quasar J1020+4320: Recently Restarted Jet Activity?

, 2013
This paper reports very-long-baseline interferometry observations of the radio-loud broad absorption line (BAL) quasar J1020+4320 at 1.7, 2.3, 6.7, and 8.4 GHz using the Japanese VLBI network (JVN) and European VLBI network (EVN). The radio morphology is
Asada, Keiichi, Doi, Akihiro, Fujisawa, Kenta, Hayashi, Takayuki J., Honma, Mareki, Jike, Takaaki, Kimura, Kimihiro, Kobayashi, Hideyuki, Koyama, Shoko, Mochizuki, Nanako, Murata, Yasuhiro, Nagai, Hiroshi, Ogawa, Hideo, Oyama, Tomoaki, Shibata, Katsunori M., Sugiyama, Koichiro, Takeuchi, Hiroshi   +16 more
core   +1 more source

Multifrequency broadband polarized horn antenna [PDF]

, 1981
A corrugated conical horn antenna is simultaneously fed a multiplicity of signals, two for each of five frequencies, with each of a pair of signals fed in each of two orthogonal planes for excitation of a desired spherical hybrid mode.
Green, K. A.
core   +1 more source

Microwave spectroscopy of the active sun [PDF]

In studies of solar active regions and bursts, the ability to obtain spatially resolved radio spectra (brightness temperature spectra) opens a whole new range of possibilities for study of the solar corona.
Hurford, Gordon
core   +1 more source

Genetic Algorithm Optimization of a High-Directivity Microstrip Patch Antenna Having a Rectangular Profile [PDF]

, 2013
A single high-directivity microstrip patch antenna (MPA) having a rectangular profile, which can substitute a linear array is proposed. It is designed by using genetic algorithms with the advantage of not requiring a feeding network.
Anguera, J., Jayasinghe, J.W., Uduwawala, D. N.   +2 more
core  

A Frequency-Selective Reconfigurable Antenna for Wireless Applications in the S and C Bands. [PDF]

Sensors (Basel), 2023
Sakkas A, Oikonomou V, Mystridis G, Christofilakis V, Tatsis G, Baldoumas G, Tritiakis V, Chronopoulos SK.   +7 more
europepmc   +1 more source

Subsurface sounders [PDF]

Airborne or spaceborne electromagnetic systems used to detect subsurface features are discussed. Data are given as a function of resistivity of ground material, magnetic permeability of free space, and angular frequency.

core   +1 more source

Miniaturized Circular-Waveguide Probe Antennas Using Metamaterial Liners

, 2014
This work presents the radiation performance of open-ended circular-waveguide probe antennas that have been miniaturized by the introduction of thin metamaterial liners.
Iyer, Ashwin K., Pollock, Justin G.
core   +1 more source

Single-, Dual- and Triple-band Frequency Reconfigurable Antenna [PDF]

, 2014
The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation.
Hamid, M. R., Idris, I. H., Jamaluddin, M. H., Kelly, J. R., Majid, H. A., Rahim, M. K. A.   +5 more
core   +1 more source

Wideband and Multifrequency Square Spiral Microstrip Patch Antenna

International Journal of Innovative Research in Computer and Communication Engineering, 2015
This paper describes the analysis and design of a class of square spiral microstrip antennas for broad frequency band and multi-frequency operations by adding suitable tuning elements in a single structure. The simulation and modeling of these configurations have been done using Ansoft HFSS software. The resonant frequencies and dimensions are computed
openaire   +1 more source

Quasi-TEM modes in rectangular waveguides: a study based on the properties of PMC and hard surfaces

, 2008
Hard surfaces or magnetic surfaces can be used to propagate quasi-TEM modes inside closed waveguides. The interesting feature of these modes is an almost uniform field distribution inside the waveguide. But the mechanisms governing how these surfaces act,
B. Gralak, G. Tayeb, R. Pierre, S. Enoch, Tayeb G   +4 more
core   +3 more sources