Monopole Antenna with a Finite Ground Plane in the Presence of an Infinite Ground
Abstract:
An experimental and theoretical study was made of a monopole antenna mounted on a finite ground plane located above an infinite ground. Circular flat discs and hemispheres were used for the finite ground planes. Experiments were conducted over a 6 to 1 frequency range, with the length of monopole antenna fixed at a quarter wavelength at the upper end of the frequency band. The radii of finite ground planes used for experiments were generally less than a quarter wavelength. Input impedances were measured as a function of frequency at the base of the antenna, using as variables the radius and the locations of the ground plane with respect to an infinite ground below. A theoretical analysis is also made of a monopole with a hemispherical ground plane on an infinite ground. Far-zone electromagnetic fields were calculated as a function of both the ground plane radius and the frequency. Radiation resistances were also calculated.