Analysis and design of microstrip antenna for ultra wideband applications

Abstract

objective of this work is analysis and design of microstrip antennas for ultra newlinewideband (UWB) systems. Ultra wide band (UWB) technology was initially developed newlinefor military applications due to its high penetration capability through obstacles and very newlineaccurate ranging up to centimeter level. The UWB system operates over a wide newlinebandwidth with directional or omnidirectional radiation pattern, constant gain in desired newlinedirection, constant polarization, high radiation efficiency etc. These systems need very newlinelow power for transmission and so don t cause significant interference to other wireless newlinesystems. An antenna is said to be a UWB antenna if it covers at least 20% of the newlinefrequency spectrum from 3.1GHz to 10.6 GHz. There are several possible UWB antennas newlinelike Dipole antenna, Vivaldi antenna, log periodic antenna etc. Here planar microstrip newlineantenna is chosen for design as this antenna family of low cost, small size and conformal newlineshape. Major challenge in this field is to achieve compact size along with wide bandwidth newlineand low manufacturing cost. newlineIn UWB frequency band, some narrowband systems such as: WLAN (3.657-3.659GHz newlineand 4.942-4.948 GHz) , WiMAX (unlicensed) (at 2.4 GHz and 5.8 GHz), WiMAX newline(licensed) (2.5GHz and 3.5 GHz), (iii) HIPERLAN (5.45 GHz 5.725 GHz) and X band newline(8GHz -12 GHz) exists. These mentioned narrowband systems are a serious cause of newlineinterference with the desired UWB system. This problem can be eliminated by the use of newlineUWB antennas with band notch characteristics. Considering above facts following newlinemethods for the design of planar microstrip antenna operating in UWB range with band newlinenotch characteristics to reduce the possibility of interference: newline1. Simple Microstrip Antenna (MSA) with defected ground structure newline2. Monopole Antenna: (a) Simple Monopole (b) Monopole with reconfigurable bands newlineDefect in the ground plane of planar MSA has capability to add band notch newlinecharacteristics in the desired frequency bands. The position and nature of notch bands can ... newline newline