Metamaterial Inspired Reconfigurable antenna for Cognitive Radio applications

Abstract

The rapid development of electronics and wireless communication led to great demand for wireless devices that can operate at different standards, concurrently. These devices require low profile, compact, high gain antennas which can handle multiple functions simultaneously. Reconfigurable antennas integrated with electromagnetic metamaterial structures is a promising solution for the above requirement. A miniaturized multiband reconfigurable Artificial Magnetic Conductor (AMC) unit cell, a zero phase reflection metasurface and a phase gradient metasurface are designed to integrate with the antenna for improving the gain and achieving beam steerability. Antennas designed for Cognitive Radio (CR) services requires switching between Ultra-Wide Band (UWB) response and multiple Narrow Band (NB) responses for the purpose of “spectrum sensing” and “communicating” respectively. Focusing on this requirement a frequency reconfigurable circular monopole antenna is designed which can switch and fine tune between UWB response and several number of NB responses. Modern wireless devices that operates on different communication standards requires, change in data rate, depending upon the requirement of application. This demands the antenna to be capable of tuning its bandwidth. Focusing on this requirement a bandwidth reconfigurable antenna is designed by integrating the metamaterial structure, complementary split ring (CSRR) with the antenna. Circular polarization with switchable polarization sense of LHCP and RHCP, is also implemented in the designed antenna. Radiation pattern reconfigurability, with a good beam steering angle is also achieved for the designed antenna by integrating phase gradient metasurface. Designed antenna is fabricated and tested in an anechoic chamber. Its measured parameters are compared with existing designs in the literature to showcase the improved performance exhibited by the designed antenna.