Beam tilting of single microstrip antenna using high permittivity superstrate

Antenna beam tilting or steering requires multiple antenna elements to be phase shifted and arranged in the form of an array. This article presents a novel method to tilt the main beam of a microstrip patch by partially covering it with a high dielectric-constant superstrate. The beam tilting is possible because of the dual-slot radiation mechanism of the microstrip antenna. In effect, the electromagnetic radiation from the covered radiating slot reaches the far-field with an additional phase with respect to the uncovered slot, resulting in an inclined beam whose angle depends on the superstrate's refractive index. Experimentally and numerically, a beam deflection of 25° is achieved when a microstrip patch is partially covered with a superstrate having a dielectric constant of 10. Moreover, the proposed structure provides gain enhancement of about 3 dB.