ANTENNA ASSEMBLY FOR RADIO CIRCUIT AND METHOD THEREFOR

摘要

An antenna assembly (100), and associated method, for a radio, such as a portable radiotelephone, which is of minimal physical dimensions and which is operable over a wide range of frequencies. A length of wire (106) is helically-shaped and includes at least a portion of winding. A capacitive top-hat (136) is positioned at an end portion of the wire. By increasing the number of windings of the wire (106), the height of the antenna assembly is reduced, but such reduction also reduces the size of the bandwidth of frequencies over which the antenna assembly is operable. Increase in the size of the surface area of the capacitive top-hat (136) increases the size of the bandwidth over which the antenna assembly is operable. Selection of the top-hat size and the number of windings permits both physical dimensions of the antenna assembly and the size of the bandwidth to be selected.