US Patent 7817101 Dual polarized multifilar antenna

Various embodiments are described of an antenna including a common ground plane, a first set of N approximately resonant elements with a length I2 and a second set of M approximately resonant elements with a length I1. The first set of N approximately resonant elements are wound to form a first helix with an initial diameter d2 and a height h2. The second set of M approximately resonant elements are wound in the opposite direction to the first set of N approximately resonant elements to form a second helix. The second helix is centrally disposed within the first helix, and d1 is less than d2 and h1 is greater than h2.