Cross-Dielectric-Slab-Loaded Archimedean Spiral Antenna

In this letter, a cross-dielectric-slab-loaded Archimedean spiral antenna (SLASA) is investigated. Cross dielectric slab (CDS) is made by two slabs (plates) of FR-4 dielectric material (dielectric constant 4.3 and loss tangent 0.025) fixed vertically at 90 ° to each other and attached on the top of the Archimedean spiral antenna. It is found that the dielectric slab significantly enhances gain of the Archimedean spiral antenna (ASA) in the bandwidth of 6:1. The gain increases with frequency, without affecting the 3-dB axial ratio in the operating frequency band. The CDS is a lightweight structure having low fabrication cost. The measured S11, input impedance, and radiation pattern are presented to support the efficacy of the proposed structure.