Interwoven Spiral Array (ISPA) With a 10:1 Bandwidth on a Ground Plane

We describe a novel, planar, circularly polarized (CP), interwoven spiral array (ISPA) having a 10:1 bandwidth while operating conformally on a perfect electric conducting (PEC) ground plane. The array is comprised of rectangular, self-complementary spirals. However, unlike typical array designs, the elements have their arms "interwoven" to enhance coupling. This coupling serves to mitigate the inductive effects contributed by the PEC ground plane. Consequently, the unit cell of the array encompasses several adjacent array elements. This feature leads to unique array properties, and in this letter, we pursue a numerical analysis and design of an array version that delivers a 10:1 bandwidth, for a broadside scan, in a conformal setting.