A wideband monopole antenna design

[摘要] ENGLISH ABSTRACT: The successful operation of a man-pack VHF jamming system requires a compact and efficient antenna operating over a wide bandwidth. The design of such an antenna is the focus of this thesis.The antenna should be of a practical size for a portable system and it must radiate energy efficiently across a frequency bandwidth in excess of a decade. A practical „target‟ specification of such an antenna has been drawn up based on the performance of a commercially available system.Several possible antenna topologies, each with a variety of loading section options, are tested using 'Full wave electromagnetic modelling (FEKO). Each topology/loading-section is numerically optimised for load element values by considering both its gain and reflection coefficient. Results of the „optimally loaded‟ solution for each topology are then compared to each other to arrive at the best overall design.The best result is found to be the traditional monopole whip-type antenna, with four R-L loading sections spread along its length. The simulated results show that the proposed antenna can be expected to meet the target standing wave ratio (SWR) specifications while offering a gain advantage of between 5 and 10 dBi higher than is available commercially. The selected design is constructed and its performance measured.

[发布机构] Stellenbosch University