A helical antenna (100) forming an integrated notch filter includes a
first helical radiating element (101) attached to a second helical
radiating element (103). The second helical radiating element is one
quarter wavelength of a resonant operating frequency. The helical antenna
(100) forms a notch filter through the use of intrinsic capacitance and
inductance in both radiating elements. The invention provides an
integrated notch filter for attenuating a predetermined range of radio
frequency (RF) signals presented to the helical antenna (100) without the
use of discrete circuit components.