Executive Summary : | The millimeter wave communication severely suffers from propagation losses and low penetration. To compensate for such losses requires highly directive antennas are required for mm-wave communication. Due to smaller wavelengths of mm-waves, larger antennas can be arrayed in a small space to have highly directional radiation beams with steering capabilities when implemented with a properly feeding mechanism. In this project, the design of compact and high gain one/two dimensional beam-switching antennas operating at millimetre wave frequencies (26.5 - 43.5 GHz) will be carried out. The antennas will be based on the transmitarray (TA)/reflectarray (RA)/reconfigurable intelligent surfaces (RIS). The phase shift elements, either passive or active will serve as a building blocks for the design of these surfaces. The TA/RA/RIS will further be illuminated by a feed antenna placed at the focus of the surface. For the TA/RA surfaces utilizing passive phase shift elements, the feed source will be a MIMO antenna whereas, for the RIS using active phase shift element, the feed antenna can be a single element. The feed MIMO antennas can be placed in a 1-D configuration or a 2-D configuration, leading to the design of a 1-D/2-D beamswitching antenna. The design and characterization of the beam-steering antennas will be carried out in an electromagnetic solver which will be followed by fabrication and measurement. The significance of the present proposal can be understood from the following: 1. Performance Parameters: The antennas will be of designed from electrically small phase shifting element, compact and planar feed element, which will further result into a small focal to dimension (f/d) ratio. The small f/d ratio will lead to the compact design of the beam-steering antenna, making it a good candidate for the massive MIMO applications. The phase shifting element will be designed from multi-layer non-resonant structures, which will lead to the wideband nature of TA/RA/RIS. The antennas can have a scanning range varying from 10o to 60o in one or two principal planes with a scanning loss less than 3 dB. The polarization of the switched beams can be made reconfigurable (linear/dual-linear/circular/dual-circular) by switching the ports of MIMO feed or controlling the bias of active elements in RIS. 2. Mm-wave communication protocol implementation: The beam finding protocol such as Fast Link will be implemented using a mm-wave 5G testbed consisting of the proposed high gain beam-steering antenna as the transmitter for both Line of Sight (LOS) and Non-LOS communication links. |