Many types of antennas can be used for digital TV receivers; in this article we try to design a double biquad antenna. This is due simple form, easy make, wide beamwidth. In designing receiver the Malang area, an STB device needed, so that analog still receive broadcasts. study, antenna made copper wire, each side length: ¼ ? , with working frequency: 650 MHz. order match impedance 75? coaxial ...

Uplink antenna arrays have the potential to greatly increase the Deep Space Network’s high-data-rate uplink capabilities as well as useful range, and to provide additional uplink signal power during critical spacecraft emergencies. While techniques for calibrating an array of receive antennas have been addressed previously, proven concepts for uplink array calibration have yet to be demonstrate...

A multiwavelength fiber laser based on multimode fiber Bragg gratings (MM-FBGs) is proposed and demonstrated. The laser, which is comprised of two MM-FBGs connected in a parallel configuration, can yield 10 stable output wavelengths using the offset launch technique.

The microwave observatory of subcanopy and subsurface (MOSS) project has been supported under the ESTO IIP to develop technologies for a SAR mission that provides global observations of soil moisture under substantial vegetation canopies and at useful depths. This VHF/UHF polarimetric SAR is designed to provide 7-10 day repeat observations of soil moisture under substantial vegetation canopies ...

Presented in this paper is a conceptual design by computer simulation of monopulse reflector antenna with dual-circularly polarized sum patterns and linearly azimuth elevation difference patterns, which can be called semi-dual antenna. The proposed consists five-element feed prime-focus parabolic reflector. novelty the consisting square waveguide channel radiator rectangular radiators. separati...

A compact printed dipole antenna with wide impedance bandwidth is proposed in this paper. This antenna consists of a pair of radiation metal arms and a microstrip-to-slotline transition structure. At the end of the feeding slotted line, a beveled slot with stepped connection structure is designed to realize an offset feeding structure for feeding the dipole antenna. By using the beveled offset ...

Calculation of a double reflector Cassegrain antenna by physical optics method with taking into account multiple reflections between the and subreflector was performed. It shown that convergence characteristics (gain, efficiency, side-lobe level) increase accounting is observed. To check same calculated electric field integral equation unknown surface currents on sub-reflector. The comparison s...

The Square Kilometre Array (SKA) project is an international effort to build the world's largest radio telescope, enabling science with unprecedented detail and survey speed.The spans over a decade now at mature stage, ready enter construction integration phase. In fully deployed state, MID-Telescope consists of 150-km diameter array offset Gregorian antennas installed in quiet zone Karoo deser...

For increasing time values, isochrons can be regarded as expanding wavefronts and their perpendicular lines as the associated orthogonal isochron rays. The speed of the isochron movement depends on the medium velocity and the source-receiver position. We introduce the term equivalent-velocity to refer to the speed of isochron movement. In the particular case of zero-offset data, the equivalent ...

This paper1 continues the study of a class of compact convex hypersurfaces in R n+1 , n ≥ 1, which are boundaries of compact convex bodies obtained by taking the intersection of (solid) confocal paraboloids of revolution. Such hypersurfaces are called reflectors. In R3 reflectors arise naturally in geometrical optics and are used in design of light reflectors and reflector antennas. They are al...