A Study on Miniaturization of Printed Disc Monopole Antenna for UWB Applications Using Notched Ground Plane

Hiroyuki KOBAYASHI  Takayuki SASAMORI  Teruo TOBANA  Kohshi ABE  

Publication
IEICE TRANSACTIONS on Communications   Vol.E90-B   No.9   pp.2239-2245
Publication Date: 2007/09/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e90-b.9.2239
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on 2006 International Symposium on Antennas and Propagation)
Category: Antennas
Keyword: 
UWB antenna,  printed antenna,  planar disc monopole antenna,  notched ground,  FDTD,  

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Summary: 
In this paper, we report the detailed investigation of novel printed disc monopole antennas for ultra-wideband (UWB) applications focusing on miniaturization of the disc radiator. First, the basic property was examined for the case of a circular disc with diameter of 50 mm, and it was found that the VSWR is less than 2 in the UWB band of 3.1-10.6 GHz when the feed gap length is between about -0.1 and 0.2 mm. Next, in order to reduce the size of the disc radiator, various dimensions of elliptical discs were investigated. It is shown that if the dimensions of the elliptical disc are chosen appropriately, a smaller disc size antenna can be achieved. To decrease the antenna size further, a triangular notch and an exponentially curved notch on the ground plane of the antenna were examined. It is observed that the use of the notched ground is very effective and that the diameter of the circular radiator can be reduced to 17 mm. The proposed antenna has an omnidirectional pattern in the x-y plane. The influence of the notch on the radiation pattern is very small. Details of the simulation results using the FDTD method and experimental results for the proposed antenna are presented and analyzed. These features are very attractive for UWB applications.