Beam focusing properties of circular monopole array antenna on a finite ground plane

This paper presents the investigation results on the beam focusing properties of a wire circular monopole array (CMA) antenna consisting of six-elements on a finite ground plane, by exciting more than one monopole at a time. The excitation of more than one element provides enhanced horizontal and vertical plane peak directivities, and a reduced 3 dB beamwidth for the horizontal pattern. The effect of varying the number of monopole elements in the array is also discussed, when only one element is excited, and the remaining ones are shorted to the ground. The antenna was fabricated and tested for its impedance and radiation characteristics for one of the excitation schemes, and the results were found in reasonable agreement with the simulations. Index Terms--Beam focusing properties, circular monopole array (CMA), finite ground, multiple excitations.