High-Gain Dielectric Endfire Antenna by Forward Scattering of Dielectric Spheres

Forward scattering of an electromagnetic wave on a spherical dielectric resonator is applied to enhance endfire directivity of tapered dielectric rod radiators. An analysis of electromagnetic wave scattering using Mie theory shows that the superposition of fundamental transverse electric and magnetic dipole modes of dielectric spheres increases directivity in forward direction. A compact arrangement with four dielectric spheres is shown to increase the directivity of a dielectric slab radiator by more than 6 dB for a prototype antenna operating around 90 GHz, and by almost 4 dB for another antenna operating at 200 GHz.