This study reports the performance of an Archimedean spiral antenna, which exhibits unidirectional circularly polarized radiation patterns with a peak gain >8 dBic in the lower (2.4–2.485 GHz) and upper (5.15–5.35 and 5.725–5.875 GHz) Wireless local area network frequency bands. The required backlobe suppression and impedance match are obtained by placing a multiresonant high impedance surface (HIS) in close proximity to the radiating aperture. Simulated and measured radiation patterns are shown at the center frequency of all three channels and a comparison of the key performance metrics is made with free space and metal backed antenna arrangements to demonstrate the enhancements which are attributed to the HIS reflector.
Mohamad, S., Cahill, R., & Fusco, V. (2015). Tri-Band HIS Backed Spiral Antenna for Wireless LAN Applications. Microwave and Optical Technology Letters, 57(5), 1116-1121. https://doi.org/10.1002/mop.29028