Non-complementary modulated arm width spiral design and application

Modulated Arm Width (MAW) spiral antennas are usually self-complementary and have the same period as arm count. In this paper we investigate the impact of non-complementary geometries. In some frequency independent structures which have periodic circuits, non-complementary behavior arises from varying that period independently of the arm count. Specifically for MAW spiral antennas, modal radiation properties can be changed by varying the period unlike varying the ratio of metal to air.