In wireless communication systems, there is an increasing demand for electrically small antennas (ESA) with wide bandwidth (at low VSWR), good omni-directional coverage, high gain and low profile. Thus great attention has been focused on the miniaturization of antennas for such applications. An ESA typically has dimensions that are rather small compared to the wavelength of operation, occupying a small fraction of a radiansphere [1]. Due to its inherent large input reactance and small radiation resistance, the bandwidth of ESA is usually narrow [1]. The disc cone antenna has been widely employed due to its broad bandwidth and good radiation efficiency. The disc cone antenna evolved naturally from a gradually tapered transmission line such that the impedance varies gradually from guided wave to free-space wave. An abrupt change in the transition between guided waves and free-space waves will result in a portion of the power being reflected back to the input terminal. This will affect the operating bandwidth of the antennas. The reduced-size disc cone antenna is studied with lumped element loading in this paper. This method of loading is appropriate for frequencies below microwave bands.
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