Reduction of Groundplane-Dependent Effects on Microstrip-Fed Printed Rectangular Monopoles

The paper describes methods to mitigate the strong dependence of impedance
bandwidth on the groundplane size for the rectangular printed planar monopole. It is
shown that the bandwidth limitation may be overcome by introducing feedline
asymmetry, which alters the purity and the Q of the higher frequency modes and by
groundplane augmentation, which effects the lower frequency modes. A method of
extending the groundplane without increasing overall antenna size is shown to
improve both the bandwidth and gain and also to enable the use of significantly
smaller groundplanes. The effects of these techniques on radiation pattern are
discussed.

CTVR - The Telecommunications Research Centre,
Science Foundation Ireland