In this study, a millimeter-wave (mmWave) dielectric resonator antenna (DRA) with an omnidirectional pattern is presented for the first time. A key feature of the proposed design is the utilization of a planar feed network to achieve omnidirectional radiation from a rectangular DRA, which has not been reported previously in the open literature. In addition, the proposed antenna offers multiband operation with different types of radiation patterns. The degenerate TE₁₂₁/TE₂₁₁ modes were excited at 28.5 GHz with an overall internal electromagnetic field distribution that was similar to that of the HEM_21δ mode of a cylindrical DRA. The achieved omnidirectional bandwidth and gain were 1.9% and 4.3 dBi, respectively. Moreover, broadside radiation was achieved by exciting the TE₁₁₁ fundamental mode at 17.5 GHz together with the resonance of the feeding ring-slot at 23 GHz. The triple-band operation offers a highly versatile antenna that can be utilized in on-body and off-body communications. Furthermore, the proposed design was validated through measurements, demonstrating good agreement with simulations.

This article delves into the capabilities of 3D-printed millimeter-wave (mmWave) layered cylindrical dielectric resonator antennas (CDRAs). The proposed design yielded promising results, boasting a remarkable 53% impedance bandwidth spanning the frequency spectrum from 18 to 34 GHz. Furthermore, the axial ratio (AR) bandwidth achieved an impressive 17%, coupled with a maximum gain of 13.3 dBic. These notable results underscore the efficacy of the proposed design, positioning it as a viable solution for applications in Beyond 5G (B5G). A novel assembly technique was also investigated, employing additive manufacturing to seamlessly merge two layers with distinct dielectric constants into a singular layer. This innovative approach systematically eliminates the potential for air gaps between layers, enhancing the antenna’s overall performance. This approach exhibited potential, particularly in the performance of a millimeter-wave circularly polarized (CP) cylindrical DRA featuring a perforated coating layer. The synergy between measurements and simulations demonstrates a remarkable alignment, providing robust validation of the effectiveness of the proposed design.

This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, λ_o, the DRA dimensions were (0.48λ_o × 0.48λ_o × 0.27λ_o) at 28 GHz. The antenna array was simulated by incorporating dielectric layers with parameters that are equivalent to those of the human body at the desired frequency of 28 GHz for off-body communications. Moreover, the precise alignment and assembly of the DRA, which pose major difficulties at mmWave frequencies, were achieved by outlining the DRA positions on the ground plane using a three-dimensional (3D) printer. The array configuration was fabricated and measured with excellent performance, realizing a measured impedance bandwidth of 29% in conjunction with an axial-ration (AR) bandwidth of 13% and a broadside gain of 13.7 dBic at 28 GHz.