Spherical Dielectric Resonator Antenna for 5G Application

— In this article Spherical DRA has been formulated , simulated and proto type developed. The detailed theoretical analysis along with simulations and measured results at 5.8 GHz have been presented in this article. The SDRA at 5.8 GHz covering 5G frewuenci band. The proposed design antenna provides the gain of 7.3 dB and return loss -25 dB. The measured results are in good match with simulated result. The proposed SDRA are good for 5G wireless networks, as well as other sub-6 band in wireless communication systems.


INTRODUCTION
Currently high data speed is a major factor using wireless technology. 5G have been started in 2017 and commercialized in 2020[1] [2]. The speed of 5G is 1GB/ second.The key characteristics of a 5G device are high performance, high speed, low latent, light weight and small size[3] [4]. The 5G technology offer the channel aggression and higher channel capacity with higher data rate. Published cellular designs have been focused on 3G/4G technology[5] [6]. The 5G network support two sets. These sets are long range sub -6 band and high capacity mmWave. The long range sub-6 GHz is for FR1 and the high capacity mmWave spectrum is for FR2 [ [22]. Authors also have done done logical study on hemispherical dielectric resonator antenna like impedance, efficiency, mode and gain have been made [23] [24]. Antenna is the most important part of wireless networks. Two class of antenna are dielectric resonator antenna and microstrip patch antenna [25] [26]. The main advantages of dielectric resonator antenna are low cost and small size [27] [28]. Dielectric resonator antenna has higher impedance bandwidth compare to microstrip patch antenna [29] [30]. Past work we have investigation into polarization of the rectangular and cylindrical DRA and design the pattern on them [31] [32]. In this article implement and design the pattern of spherical DRA. We used the spherical DRA for the higher order mode and high gain. The SDRA is designed using CST software. This article is organized as follow. Section II antenna design and its dimensions, Section III formulations, Section IV result and discussion and Section V conclusion.
II. ANTENNA DESIGN SDRA( Spherical dielectrics resonator antenna) was placed on slotted ground plane and simulated with the help of HFSS (antenna design software). Here we have used silicon (Er=10) dielectric material for SDRA which is easily available around us. Here the aperture coupling has been used to feed the antenna. SDRA as a dielectric cause lower conduction losses. Compact size of SDRA make it more suitable for use in antenna design. Its high gain, high bandwidth and low losses increase the overall performance of the antenna. The geomatry of proposed spherical dielectric resonator antenna is given in figure 1.
The proposed design is fabricated on commercially available FR1 substrate with permittivity 10 and loss tangent 0.0001. The proposed SDRA dimensions are comparable with the size of latest 5G devise available. The propotype antenna is given in figure 2

Figure. 2. Spherical DRA
Most spherical, cylindrical, rectangular and conical shaped DRA operate at the elemental resonance. Spherical permits for small size with specific dielectric material permittivity. The resonance frequency is 5.8GHz with a sphere diameter 10 mm. The centre of the resonator has higher Efield magnitude. The SDRA to achieve a minimum return loss. The dimentions of the designed SDRA are given in table 1. The size of all geometry are in MM.    The results of measured and simulated return loss are given in figure 4. The 10dB simulated impedance bandwidth is 5.5-5.4GHz.The 10dB measurd impedance bandwidth is 5.5-5.9GHz. The impedance bandwidth of measured and similated antennas are 7% and 5.4% respectively.  The electric field in SDRA is given in the figure 5. The electric field parameters have been obtained. The study of electric multipole resonator at microwave frequency is most important for radiation pattern. The magnetic field in SDRA is given in the figure 6. The magnetic field parameters have been obtained. The study of magnetic multipole resonator at microwave frequency is most important for radiation pattern .

Figure.6. H -field in spherical DRA
This is clear that magnetic fields and electric fields have element in x-axis, y-axis and z-axis of the coordinate system. proposed SDRA has higher gain. The proposed antenna has get better radiation quality.

V. CONLCUSION
The proposed SDRA structure is simply and easily to be fabricated.The SDRA designed at 5.8 GHz.The SDRA has impedance bandwidth 7% and a gain 10 dB.The SDRA Return loss is -26dB. The proposed SDRA is well used for in 5G or wireless communication system.The far fields formulations have also been developed. The quality factor for microwave spherical DRA has been formulated. The main objective of the antenna design is to capture useful signals available in the surrounding in the range of microwave frequency and utilizes the same for various 5G applications in the different fields.