Abstract: An antenna assembly, 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 is helically-shaped and includes at least a portion of a winding. A capacitive top-hat is positioned at an end portion of the wire. By increasing the number of windings of the wire, 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 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 beth physical dimensions of the antenna assembly and the size of the bandwidth to be selected.

Abstract: A nondirectional antenna assembly, and associated method, for a radio operative at high frequencies, such as at frequencies of approximately 1.8 Gigahertz. A first antenna portion, formed of a one-half wavelength, helical winding is supported at a distal side of a nonconductive whip. A second antenna portion, comprised of a helical winding supported at a proximal side of the nonconductive whip, and a one-quarter wave helical winding, connected to radio circuitry of the radio transceiver, couples the first antenna portion to the radio circuitry. Because the first antenna portion is positioned at a distal side of the nonconductive whip, shadowing occurring as a result of positioning the radio transceiver proximate to a user during operation thereof is less likely to interfere with operation of the radio transceiver.