Polarization Reconfigurable Broadband Dielectric Resonator Antenna With a Lattice Structure

In this paper, a novel technique to design a broadband circularly polarized dielectric resonator antenna (DRA) with a lattice structure is proposed for the first time. Two resonant modes of TE111 and TE211 can be simultaneously excited through a cross-slot to constitute a wide operating bandwidth. On this basis, its reconfigurable version, which can operate in left-handed circular polarization (CP), right-handed CP, and linear polarization (LP) states, has been further presented. The latter possesses a simple design procedure to implement the reconfigurability since all the reconfigurable feeding circuits are isolated from the radiating DRA by the ground plane and only five p-i-n diodes are needed. Besides, a Teflon-based template is adopted to solve the problem of dielectric blocks' critical placement and alignment tolerances. A backed cavity based on substrate integrated waveguide technology is introduced to reduce the unwanted radiation from the surface wave. Measured results indicate that the reconfigurable prototype can achieve a 3-dB axial ratio bandwidth of 20.7% for CP states, an impedance bandwidth of 29.6% for LP state with a cross-polarization level of better than -20 dB, and a peak gain over 7.3 dBi for all states. The proposed antenna can be used for polarization diversity applications of the modern wireless system.