tailieunhanh - Báo cáo hóa học: " Influence of the Antennas on the Ultra-Wideband Transmission"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Influence of the Antennas on the Ultra-Wideband Transmission | EURASIP Journal on Applied Signal Processing 2005 3 296-305 2005 Hindawi Publishing Corporation Influence of the Antennas on the Ultra-Wideband Transmission Werner Sorgel Institutfur Hochstfrequenztechnik und Elektronik Universitat Karlsruhe TH Kaiserstrasse 12 76128 Karlsruhe Germany Email Werner Wiesbeck Institutfur Hochstfrequenztechnik und Elektronik Universitat Karlsruhe TH Kaiserstrasse 12 76128 Karlsruhe Germany Email Received 29 October 2003 Revised 16 February 2004 Spectrum is presently one of the most valuable goods worldwide as the demand is permanently increasing and it can be traded only locally. Since the United States Federal Communications Commission FCC has opened the spectrum from GHz to that is a bandwidth of for unlicensed use with up to dBm MHz EIRP numerous applications in communications and sensor areas are showing up. Like all wireless devices these have an antenna as an integral part of the air interface. The antennas are modeled as linear time-invariant LTI systems with a transfer function. The measurement of the antenna s frequency-dependent directional transfer function is described. Quality measures for the antennas like the peak value of the transient response its width and ringing as well as the transient gain are discussed. The application of these quality measures is shown for measurements of different UWB antennas. Keywords and phrases ultra-wideband ultra-wideband antennas quality measures for UWB antennas time-domain antenna characterization transient radiation and reception. 1. INTRODUCTION In April 2002 the Federal Communications Comission FCC has released the first report and order regarding the application of ultra-wideband UWB communication devices 1 . The antennas are an essential part of such systems as of any wireless system. All antenna s properties depend strongly on the frequency. Therefore the transmitted waveform is filtered by the antenna