###### Abstract  
In this article, a rectangular dielectric resonator antenna (RDRA) with circularly polarized (CP) response is presented for 5G NR (New Radio) Sub-6 GHz band applications. A uniquely shaped conformal metal feeding strip is proposed to excite the RDRA in higher-order mode for high gain utilization. By using the proposed feeding mechanism, the degenerate mode pair of the first higher-order, i.e., TE\({}_{513}\) at 4.13 GHz and TE\({}_{183^{\prime}}^{\prime}\) at 4.52 GHz is excited to achieve a circularly polarized response. A circular polarization over a bandwidth of \(\sim\)10%, in conjunction with a wide impedance matching over a bandwidth of \(\sim\)17%, were attained by the antenna. The CP antenna proposed offers a useful gain of \(\sim\)6.2 dBic. The achieved CP bandwidth of the RDRA is good enough to cover the targeted 5G NR bands around 4.4-4.8 GHz, such as n79. The proposed antenna configuration is modelled and optimized using computer simulation technology (CST). A prototype was built to confirm (validate) the performance estimated through simulation. A good agreement was observed between simulated and measured results. dielectric resonator antennas; strip-fed antennas; axial ratio; 5G NR band; Sub-6 GHz 202  
The 5G NR is a multi-band spectrum and n79 (4.4-4.8 GHz) is one of the major focuses for future 5G communications in different parts of the world, such as China, the EU, and Japan [2]. In literature, different 5G antennas have been reported so far [3,4]. In the last few decades, the dielectric resonator antenna (DRA) has been acquiring a lot of attention from antenna researchers. This is due to their significant benefits over conventional microstrip antennas. DRAs offer high bandwidth, negligible metal losses, small size, and fixable excitation techniques which make them a potential candidate for high-frequency modern networks, such as 5G [5, 6, 7, 8, 9, 10, 11, 12]. DRAs can be designed in different shapes for desired applications but complicated shapes add complexity and design configurations are expensive. So basic dielectric resonator (DR) shapes, such as rectangular, cylindrical, and hemispherical are much more popular because of ease in fabrication and low cost. Among these basic shapes, rectangular is much preferred because of design flexibility. In the rectangular shape, the height to width and depth to width aspect ratios have a direct impact on resonance frequency and Q-factor of the radiation. Moreover, using the dielectric waveguide model (DWM), the DR profile and impedance bandwidth characteristics of the rectangular DRA can be predicted [13]. In this era of modern communication, reliability of the communication system is highly important. That is why circularly polarized communication networks are very much preferred as compared to linearly polarized communication networks [3]. A lot of circularly polarized DRAs are reported in the literature using dual feeding techniques, but with limitations, such as complex feeding networks and larger sizes, which make them useless for modern communication [14, 15, 16]. The generation of circular polarization in DRA using a single feeding network is quite challenging. Some authors performed cutting and drilling of the dielectric resonator, some used multi-layered DRs, having metallic walls surrounding the RDRA, and more than one DR has been reported as well. All such arrangements are complex, heavy, and costly [17, 18, 19, 20]. Different DRAs using a single feeding mechanism have been reported in the literature [18, 19, 20, 21, 22]. In [18], a multi-layered rectangular DRA, excited by a cross-slot coupled with a microstrip feeding mechanism providing 9.5% of CP response, has been reported. As demonstrated in [19], a feeding technique comprised of cross-slot and microstrip was used to generate a 46.9% CP wave by a rectangular DRA surrounded by four metallic walls.