Design of Different Shaped DRAs for 60 GHz Millimeter-wave Applications

This paper features, a comparative study of four different shaped dielectric resonator antennas (DRAs) for 60 GHz millimeter-wave applications. The proposed antennas are of different shapes i.e. cylindrical dielectric resonator antenna (CDRA), rectangular dielectric resonator antenna (RDRA), hexagonal dielectric resonator antenna (HDRA) and octagonal dielectric resonator antenna (ODRA) and each of the antenna is fed by a 50 Ω microstrip line. These are placed on a silicon layer substrate ( εr1=4), of 1.6 (Lsub1)×1.6(Wsub1)×0.022(Hsub1) mm³, followed by another silicon layer substrate ( εr2=11.9), of 1.6 (Lsub2)×1.6(Wsub2)×0.3(Hsub2) mm³, This is placed on the bottom of DR. For the dielectric resonator (DR), high dielectric constant materials are used, Ca₅Nb₂TiO₁₂ ( εr=48). Simulated S₁₁for each of the antennas ≤ -10 dB, which covers an impedance bandwidth from 52.7- 62.8 GHz for CDRA, 57- 62.2 GHz for RDRA, 55.8- 64.6 GHz for HDRA and 54.2-63.5 GHz for ODRA. Other parameters such as gain, antenna efficiency, directivity and radiation pattern are obtained using the EM solver CST microwave studio and reported in this paper.

I. Introduction

The release of unlicensed 60 GHz band and development of 5G technologies (millimeter-wave communications), that is aimed at increasing data rate on a wireless communication network by a factor of 100, imposing stringent specifications like: large impedance bandwidth, high gain, low profile and temperature independent capability on the design of the radio frequency electronics [1]. Millimeter-wave, demonstrated by Sir J.C. Bose in the year of 1985. This wave was also termed as the extremely high frequency (EHF) and frequency band of spectrum lies in between 30–300 GHz, having short wave length range from 10mm-1mm. In order to accumulate them, various front-end antenna solutions are available, in the likes of monopoles, dipoles and patch antennas. These antennas are characterized by low profile & they are easily integrated on chip. However, unless advanced design solutions based on integration of dielectric superstrates and lensing structures are used, antennas typically suffer from reduced radiation efficiency and narrow impedance bandwidth. On the other hand, these DRAs [2] are one of the promising candidates, to replace traditional radiating elements like microstrip patch at high frequencies, especially for applications at the millimeter waves [4]. This is mainly attributed to the fact that DRAs do not suffer from conduction losses & can be characterized easily.