Nowadays, Wireless Technology is evolving with fast speed [1]. Mostly many of the present communication instruments & device operates in a spectrum, less than 3GHz (cellular spectrum) [2]. The frequency spectrum being used presently, is heavily crowded due to increase in the quantity of devices. This problem is resolved by using milli-meter wave frequency because it is minimally used &.therefore it is a better choice for future 5G Technology [2].
Milli-meter-wave bands includes:-26, 27, 28, 38 & 60 GHz [3]. The most suitable band for the 5G communication systems are 27, 28 & 38 GHz because they have least atmospheric absorption [4].Here Dielectric Resonator is choosed because it does not have metallic parts,which becomes lossy higher frequencies [5].DRAs Various aspects like:-merging, bandwidth enhancement techniques, optimization & modelling technique for constructing DRAs are studied extensively before starting the designing & simulation [6]. DRA is made of a dielectric structure which is not conducting & offers very low loss and excited with a Micro-strip feeding line.
From the Past researches,different shapes of Dielectric Resonator are provided in the literature [7] like:-cone, cylinder, rectangle, hemisphere etc. &designing methods forabove mentioned shapes are explained [7].
WCNC-2021: Workshop on Computer Networks & Communications, May 01, 2021, Chennai, India. EMAIL: armansingh4147@gmail.com (Arman Singh) ORCID: 0000-0003-4497-4889 (Arman Singh)
In the literature,different composite designs of DRA are explained well [8].The composite cylindrical DRAs have also been studied [9].The hemi-sphere structure perfectly radiates uniform radiations.This composite structure produces larger bandwidth, enhanced gain and improved radiation pattern. Here, DRA is excited by using micro-strip excitation technique [10]. The number of researches in past is very less in field of Q-HDRA. This paper target is to explore the capability of the proposed structure at 27.176GHzfrequency& also to attract Antenna designers for making more progress in the composite design field of DRA. In this Research paper, one small size structure of antenna is proposed that consists of 2 QHDRAs & 1CDRA [11] which operates at frequency of 27.13 GHz. Micro-strip slot aperture feeding technique was used for feeding the DRA .
In this paper, the QHDRA one was prepared by cutting ¼ part from a whole complete sphere. The sphere radius was about 2 mm. Similarly the second QHDRA has been designed with the equal radius but QHDRA 2 was cut in a way that it was smaller than QHDRA 1.The ¼ parts cut from the Sphere are placed side by side thereby forming combined QHDRA structure. A CDRA was also attached to the Combined QHDRA structure, thereby forming the proposed design.The Antenna structure shown in figure 1 is feeded by MSA feedingtechnique.The Return Loss graph is shown in figure 5. The designed Antenna shows a dip of -62 db (approx). The designed antenna resonate at 27.176 GHzfrequency. The Gain of the designed antenna is 6.2 dbi at 27.176 GHz frequency as shown in figure 10. Figure 6 & 7 shows radiation pattern Corresponding to S 11 minima frequency in principal planes.
The radiation pattern indicates that the proposed structure has a broadside radiation pattern in all the bands.Figure 8 shows the proposed antenna structure efficiency. The Efficiency is 0.802(80.2%)which was observed at 27.176 GHz frequency. Impedence (Z-Parameter) matching with 50 ohm connector is very good and is shown in figure 9. The admittence (Y parameter) is shown in figure 12.The Proposed Antenna Structure has a very good VSWR i.e. 1 at the resonance frequency (27.176GHz) shown in figure 11. Here the VSWR value denotes that voltage has a constant magnitude along the transmission line.
A Composite Antenna design which consist 1 CDRA & 2 QHDRAs is proposed which can be used for future 5G uses. The operating bandwidth of 2.8GHz & Gain of 6.2 dbi is achieved.The Proposed Antenna Structure provides sufficient bandwidth at 27.176 GHz which is quite suitable for intended 5G applications.