Spiral antenna on broadband uniform-height progressive EBG structure without vias

Spiral antennas work over broadband, but conventional EBG structures work over narrow frequency band. Bandwidth of EBG structures can be increased by cascading EBG vertically in multiple layers or progressively in a single layer. This paper presents a uniform height via-less broadband progressive EBG structure designed for spiral antennas. The design is fabricated and simulated boresight gain and return loss performances are compared against measurements. The effects of feed point soldering to the spiral are also discussed.