A study on the enhancement of gain and axial ratio bandwidth of the multilayer CP-DRA

In this paper, a multilayer CP-DRA(Circularly Polarized Dielectric Resonator Antenna) using-slot-feed is studied to enhance gain and axial ratio bandwidth. First, a single layer CP-DRA is studied as a reference for comparison. Then a new type of multilayer CP-DRA is proposed to enhance the gain and axial ratio bandwidth. In consideration of the antenna gain enhancement, the spacing between the elements of the multilayer CP-DRA is examined through analysis of the radiation performance of a 2 × 2 planar array of DRAs with a spacing of 0.7 λ₀ and 1.2 λ₀ using CST Microwave Studio for comparison. The measured result shows that the gain and bandwidth of the multilayer structure is approximately twice that of the single layer one. In the case of the array antenna, in which the spacing between multilayer CP-DRA element is 1.2 λ₀, a grating lobe is reduced, in contrast to what we can expect from a conventional antenna array. The measurements show that gain, impedance bandwidth and axial ratio bandwidth are 13.4 dBi, 2.2 GHz and 0.8GHz, respectively.