Real-time imaging and wavevector analyses of radio waves incident to electromagnetic absorbers
Radio waves incident to electromagnetic absorbers have been experimentally visualized for the first time, which has been accomplished by the real-time visualization method for high-frequency electric field distributions: the live electrooptic imaging technique. Imaged have been electromagnetic reflections, refractions, and standing wave formations at sheet absorbers as well as gradual variations of wave fronts at a ravine plane of pyramidal absorber. Their wave properties have been clarified qualitatively as well as quantitatively by experimental mapped wave vectors.
Comparison of Ergodic Capacities From Wideband MIMO Antenna Measurements in Reverberation Chamber and Anechoic Chamber
It has previously been shown that ergodic multiple-input-multiple-output (MIMO) capacity of a multiport antenna system can be conveniently determined from channel measurements in a reverberation chamber. In this letter, we compare such MIMO capacity results to results based on measurements in an anechoic chamber of the embedded far-field functions and efficiencies at all antenna ports. The comparison is performed over two-octaves bandwidth by using the decade bandwidth eleven antenna, a log-periodic dual-dipole array. The agreement between the reverberation chamber results and the anechoic chamber results is good over the entire frequency band 2-8 GHz.
Pioneer 10 Observations of the Ultraviolet Glow in the Vicinity of Jupiter
A two-channel ultraviolet photometer aboard Pioneer 10 has made several observations of the ultraviolet glow in the wavelength range from 170 to 1400 angstroms in the vicinity of Jupiter. Preliminary results indicate a Jovian hydrogen (1216 angstrom) glow with a brightness of about 1000 rayleighs and a helium (584 angstrom) glow with a brightness of about 10 to 20 rayleighs. In addition, Jupiter appears to have an extensive hydrogen torus surrounding it in the orbital plane of Io. The mean diameter of the torus is about equal to the diameter of the orbit of Io. Several observations of the Galilean satellites have also occurred but only a rather striking Io observation has been analyzed to date. If the observed Io glow is predominantly that of Lyman-α, the surface brightness is about 10,000 rayleighs.