Analysis And Design Of Cavity-backed Multislot Antennas With Low Cross-polarization Performance

Recently, with the rapid devrlopment of wireless communication, the design of indoordistribution antennas has been of great important to meet the needs of indoor signal coverage andenhancement. However, though some novel indoor distribution antenna designs have been proposed,most of them have various deficiencies such as complicated structure, high cost, not enoughoperational bandwidth and etc. In addition, the radiation pattern of these antennas may be distortedsignificantly due to the relative high cross-polarization level in horizontal plane with the operationfrequency increasing. Therefore, it is necessary to develop and analyze indoor directional antennawith broadband and low cross-polarization performance.In this thesis, a novel microstrip-fed cavity backed multislot antenna with lowcross-polarization performance, wide bandwidth, simple structure and easy implementation isproposed. The main content of this thesis is organized as follows:1. Firstly, this thesis introduces the development general situation of the indoor distributionantenna and the research background of the antenna with low cross-polarization performance,highlights the importance of low cross-polarization characteristics in the research of indoordistribution antennas. The multislot microstrip-fed antenna is proposed. At the same time, the thesisalso introduces the basic theory about the antenna.2. Then, this thesis discusses principal analysis method of microstrip slot antenna, such asTransmission Line Model, Cavity Model and so on. An equivalent circuit model of microstrip-fedmultislot antenna is analyzed by employing ADS and the mechanism of broadband design isconcluded.3. Finally, a multislot antenna with broden bandwidth and a cavity-backed multislot antennawith low cross-polarization performance are designed and simulated by using IE3D. In order toinvestigate the actual performance of two antennas, they are experimentally studied by using thenetwork analyzer and NSI-800F-10x far field test system. Comapred with conventional wide slotmicrostrip antenna, it is shown that the proposed cavity-backed multislot antenna has lowcross-polarization merits.