Dr. John Howard
 Write for Microwaves & RF
2 results found for Dr. John Howard, displaying items 1 - 2

March 2010   [Components]
Forecast Rain Effects On Microwave Links
Propagation of electromagnetic (EM) waves through the air is difficult to predict, due to atmospheric effects. Raindrops, for example, can act as scatterers that attenuate and affect the polarization of the propagating EM waves. Scattering theory has treated effects on the far-field regions of receive and transmit antennas in communications links, but not near-field effects. In this first of a two-part article, this analysis examines the nearfield ...

June 2008   [Communications]
Multibeam Antenna Serves Broadband Wireless Coms
Multibeam antennas can provide increased wireless communications capacity with enhanced spectral efficiency and higher quality of service. One approach to designing such an antenna involves the use of space division multiple access (SDMA) techniques. SDMA methods provide high user capacity in a limited frequency spectrum without any major technological changes.1 SDMA techniques, which are implemented by most wireless service...