3-D-Printed Wideband Multi-Ring Dielectric Resonator Antenna

A three-dimensional (3-D)-printed wideband multi-ring dielectric resonator antenna (DRA) is investigated for the first time. It consists of four concentric dielectric rings with decreasing effective dielectric constants in the radial direction. To facilitate the 3-D-printed design, a basic unit cubic cell that can be easily adjusted to provide different effective dielectric constants is used. An axial coaxial probe is used to excite the DRA in three transverse magnetic (TM) modes (TM_01δ , TM_02δ , and TM_03δ ), which are merged to provide a wide impedance bandwidth. For demonstration, a prototype operating in C-band is designed and fabricated using a 3-D printer. Its reflection coefficient, radiation pattern, antenna gain, and antenna efficiency are measured, and reasonable agreement between the measured and simulated results is observed. The prototype has a wide measured 10-dB impedance bandwidth of 60.2 % (4.3-8.0 GHz) with a low profile of 0.18λ₀, where λ₀ is the wavelength in air at the center frequency (6.15 GHz). The prototype has an average measured antenna efficiency of 89 %, with the peak efficiency given by 95 %.