Switchable dielectric resonator antenna array for fifth generation applications

Abstract

A new generation in telecommunication technology has evolved into 5G. Due to its shorter wavelength compared to the previous generation, this technology requires a wide bandwidth and high gain antenna to compensate for the added losses at a higher frequency. Therefore, a phased array capable of steering the direction of beam with high gain can be used to recover any additional losses. A dielectric resonator (DR) with a dielectric constant of 10 is used in the phased array antenna design and integrated on Rogers/RT Duroid 5880 with a conductor coating of 17.5 µm, a thickness of 0.254 mm, dielectric constant, of 2.2 and loss tangent, of 0.001. All designs are simulated using Ansoft High Frequency Structural Simulator (HFSS) and the numerical analysis involved is done by using MATLAB. The performance of the reflection coefficient and the bandwidth of the fabricated antenna are verified using Vector Network Analyzer (VNA) while the radiation pattern and the antenna gain are tested in an anechoic chamber. The proposed switchable dielectric resonator antenna (DRA) array at 15 GHz is formed through three design stages. The first stage is formed by a single element DRA placed on the ground plane and fed through a narrow aperture. The impedance bandwidth achievable is 2.5 GHz for DRA excited in mode compared to 1.8 GHz for DRA excited in mode. Besides, the gain of the antenna has improved approximately by 10 dBi in comparison to 5.6 dBi when it was excited in mode.Then, a design is formed using three elements of DR named as DRA sub-array design. The driven DR at port 1 is fed by radio frequency (RF) source and the parasitic DRs at port 2 and 3 are excited by the driven DR through mutual coupling effect. A steerable beam is achieved by switching the termination capacitor on the parasitic elements. Then, two DRA sub-array configurations are designed and named as configuration A and configuration B, respectively. Both configurations are excited by a driven DR in mode while the parasitic DRs for configurations A and B are excited in the modeand mode, respectively. From the observation, configuration B demonstrates improved performance with steering angle and maximum gain of 9.63 dBi. Furthermore, configuration B has a narrower beamwidth compared to configuration A. The final stage design is formed by incorporating configuration B with a combination of two driven DRs using power divider and phase switching. The switchable DRA array achieved a maximum gain and bandwidth of 12.8 dBi and 3.1 GHz, respectively. Moreover, the switchable DRA array is able to steer at three various steering angles which are 0 , -30 and +30 with 3 dB beamwidth around 24 by using only 2 ports. Hence, the switchable DRA array is capable to cover 60 sector which is considered suitable for 5G applications