Patent ID: 7978148

Claim:
A quadrifilar helical antenna for connecting to a feed conductor having a first and a second conductive element, the antenna comprising: a first pair of filars having a first length and comprising a first and a second filar each helically oriented between an antenna base and an antenna top; a second pair of filars having a second length different from the first length and comprising a third and a fourth filar each helically oriented between the antenna base and the antenna top; a substrate supporting a conductive H-shaped pattern for receiving a first end of each one of the first, second, third and fourth filars at a free end of each leg of the H-shaped conductive pattern, wherein a first region of the conductive pattern connects the first and the third filars and a second region of the conductive pattern connects the second and the fourth filars; a first reactive element for connecting between the first region and the first conductive element; wherein the second region is connected to the second conductive element; a second reactive element for connecting between the first and the second conductive elements a first conductive bridge for connecting a second end of the first and the second filars proximate the antenna top; and a second conductive bridge for connecting a second end of the third and the fourth filars proximate the antenna top, wherein the first and the second conductive bridges are spaced apart by a distance d, such that a length differential between the first and the second pairs of filars is responsive to the distance d.