We introduce a new parameter, symmetric average, which measures the asymmetry of a given non-degenerated convex body K in Rn. Namely, sav(K) = infa∈intK ∫ Ka ‖ − x‖Ka dx/|K|, where |K| denotes the volume of K and Ka = K − a. We show that for polytopes sav(K) ≤ C ln N , where N is the number of facets of K. Moreover, in general n n+1 ≤ sav(K) < √ n and equality in the lower bound holds if and on...

Active antenna arrays working at higher frequencies result in higher packaging densities. The antenna array under consideration operates at about 30 GHz and will be installed in an aircraft. Commercially available power amplifiers at these frequencies have an efficiency of typically 20 %, which results in high amounts of dissipated heat for the required high radiated power. The dissipated power...

in this paper satellite wave propagation at ku and ka band is considered. the design and simulation of a typical satellite beacon receiver at ka band is designed and simulated for the future works. also rain attenuation prediction at ku band using satellite signal beacon measurement and simulations for iran telecommunication research center (itrc) are presented. the measurement setup consists o...

this paper presents the design and simulation of a typical ka band satellite beacon receiver for propagation experimentation. using satellite beacon signal as a reference signal in satellite wave propagation study, is one of the most important methods. satellite beacons are frequently available for pointing large antennas, but such signals can be used for measuring the effect of natural phenome...

As part of the NASA International Polar Year activities, a Ka-band cross-track interferometric synthetic aperture radar recently demonstrated high precision elevation swath mapping capability. This proof-ofconcept instrument was achieved by interfacing antennae and Ka-band electronics with the Jet Propulsion Laboratory’s L-band UAVSAR. Deployed on the NASA Gulfstream III, initial successful eng...

This paper presents the design and simulation of a typical Ka band satellite beacon receiver for propagation experimentation. Using satellite beacon signal as a reference signal in satellite wave propagation study, is one of the most important methods. Satellite beacons are frequently available for pointing large antennas, but such signals can be used for measuring the effect of natural phenome...

The 3-D particle-in-cell (PIC) simulations of a Ka-band coupled-cavity traveling-wave tube (CCTWT) are shown. The computational analysis of the Ka-band coupled-cavity slow-wave structure was conducted through the use of an electromagnetic PIC code MAGIC3D. The choice of a double-slot staggered RF cavity circuit was made because of a wide frequency bandwidth, moderate interaction impedance, and ...

With the consideration of the existing Ka-band satellite channel model in data processing method deficiency, the Ka-band satellite channel propagation characteristic is analyzed and the influence of meteorological factors on the satellite channel is discussed. The channel of meteorological factor principal component is obtained by using the principal component analysis and fuzzy clustering anal...

Statistics for atmospheric-noise-temperature data at a 31.4-GHz frequency were calculated for the Madrid and Goldstone Deep Space Communications Complexes from the data collected by the water vapor radiometer. These data consist of 74 months of measurements at Madrid and 46 months of measurements at Goldstone. The statistics then were used to optimize a deep-space 32-GHz (Ka-band) link at each ...