A Planar Dual-Arm Equiangular Spiral Antenna

The design is described of a planar dual-arm equiangular spiral antenna incorporated with chip resistors inside the substrate. The chip resistors were applied to this equiangular spiral antenna to achieve 9:1 impedance bandwidth (2 to 18 GHz) with an extremely low profile structure. The simulated and measured magnitude of the reflection coefficient (
S

₁₁
), gain, and measured radiation patterns are presented.