Design and Analysis of Wideband Antennas for Ultra-Wideband Communication and Impulse Radar system Applications
| Autor: | Shiou-Li Chen, 陳秀莉 |
|---|---|
| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 In this dissertation, two pairs of novel planar wideband antennas with opposite polarization are presented for ultra-wideband communication and impulse radar system applications. A novel ultra-wideband (UWB) antenna which consists of a tapered loop radiator and a coplanar waveguide-to-coplanar stripline (CPW-to-CPS) transition is investigated in both frequency- and time-domain firstly. The antenna possesses a wide impedance bandwidth and shows similar radiation patterns and 3.3 to 7dBi peak gain from 3.1 to 10.6 GHz. Two additional short-circuited slots are symmetrically located on the tapered loop radiator to achieve the 5-6 GHz band-notched behaviors. The time-domain characteristic of the transmitting/receiving antenna system in multipath propagation channel is also described by antenna transfer function and examined by pulse fidelity. The proposed antennas with broad bandwidth and low pulse distortion are good candidate for UWB applications. Secondly, a novel impulse radar antenna system for the shape and position of single- and multi-object detections is investigated. In the radar object pulse response measurements, a broadband series-fed circularly polarized microstrip antenna (SFCPA) with frequency beam-scanning is excited an impulse waveform and which is received by a wideband micrstrip-fed circularly polarized spiral antenna. The object position and shape could be recognized from radar resolution technology and channel impulse response due to scattering field from object surface. After deconvolution and numerical calculation of the measured results, the estimated dimensions and positions of the metallic objects are exhibited the least 86% similarity with reality. The proposed radar antenna system improves the complexity of the conventional radar system and increases the efficiency of target detection in radar imaging applications. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|