Patent ID: 7173576

Claim:
A quadrifilar helical antenna, comprising: a substantially cylindrical substrate defining axially spaced-apart base and end regions; first and second helical filar segments each having a first length and each defining a first end proximate the base region, the first and the second filar segments extending toward the end region; second and third helical filar segments each having a second length different than the first length and each defining a first end proximate the base region, the third and the fourth filar segments extending toward the end region; and an impedance matching element disposed proximate the base region and comprising legs extending from a center region, each leg conductively connected to the first end of one of the first, the second, the third and the fourth filar segments, the impedance matching element further comprising a feed terminal in the center region, the impedance matching element for matching an antenna impedance to a source impedance.