Beam Steering of Single Microstrip Antenna Covered with Tunable Metamaterial Superstrate for 5G Wireless Communication

With the increasing wireless systems requirements for higher data rate, wider bandwidth, and miniaturized wireless terminals, more attention has been directed towards the millimeter-wave band. For instance, the frequency band around 28 GHz has recently received great interest because of the large amount of bandwidth of about 6 GHz, from 25 to 31 GHz, that is available for use. This band has been identified recently in Europe, USA, China and Korea for 5th generation wireless communication networks. Furthermore, the use of this frequency band for the design of wireless systems has several advantages such as the availability of a large bandwidth that can easily resolve the crowded spectrum challenge at microwave at lower frequency bands. Additionally, the fact of operating at short wavelengths allows to design high-gain antennas with reasonable size, which leads to compact and inexpensive RF systems. However, the propagation path loss caused by the small wavelength at millimeter-wave bands is very high, which reduces significantly the coverage range of the wireless applications. To reduce this effect at mm-wave bands, high-gain antennas with dynamic radiation pattern or beam scanning capability can be used. Indeed, using this approach, the radiation beam can be steered or redirected in order to track mobile users or desired RF signals, leading to improved transmission quality and increased coverage range. Recently, a useful feature of a microstrip antenna partially covered with a dielectric material (i.e., superstrate) has been reported, this feature is the control of the direction and beamwidth of the main beam of the antenna. By partially covering the microstrip antenna with a high refractive index superstrate, it was possible to deflect the main beam of the antenna in different directions. However, the superstrate has to be displaced mechanically to provide the dynamic beam steering capabilities, and this mechanical movement is not practical and adds to the complexity and cost of the radiating system. This challenge can be overcome by having the superstrate stationary and electronically tune the electric or magnetic properties ( or ) of the superstrate material through some external biasing voltage sources.In this project, we propose to design a tunable artificial metamaterial-based superstrate to steer the beam of a single RF source (i.e., patch antenna) operating at the 28 GHz band for 5G wireless applications. By integrating a tuning-element (i.e., varactor diode) inside the unit cell of the metamaterial superstrate, the refractive-index of the superstrate can be varied in a specific range. Then, this tunable metamaterial superstrate will be placed above a patch antenna to steer the radiated beam in different directions in the elevation planes with a scanning angle of +/- 40 to 60 deg. The size of the proposed reconfigurable antennas at the millimeter-wave band of 28 GHz would correspond to a few centimeters, which leads to a compact and practical design. The design will be fabricated, tested and measured at the Antennas and Microwave Structure Design Laboratory (AMSDL) at KFUPM as well as at the Institute National de la Recherche Scientifique (INRS) in Montreal, Canada. The estimated period of the project is 18 months with a proposed budget of 99,950 SAR. This project will allow for the scientific collaboration between KFUPM, Saudi Arabia and INRS, Montreal, Canada. Moreover, the project will allow the theoretical and experimental training of two graduate students at KFUPM.