Pattern-Reconfigurable Metasurface-Antenna Array for Functional Brain Imaging Applications

In this paper, a compact bow-tie dipole antenna with the pattern reconfigurability characteristics is presented for cerebrovascular monitoring. In order to create a pattern reconfigurable characteristic a balun-matched bow-tie antenna is equipped with a pentagonal shaped metasurface structure with five triangular meta-atoms. The proposed structure with a multi-layer phantom of the human head inside a designed matching medium are simulated in CST medium. To enhance the frequency range to have return loss less than 10 in 0.5-5 GHz, a matching medium is used. In addition, by using these metasurface structure the realized gain is increased from 1.29 dBi to 2.38 dBi at 3 GHz. The inserted pin-diodes on the triangular corners can provide the desired pattern reconfigurability. Hence the main beam direction can be controlled. Simulated reflection and radiation results demonstrate that the proposed meta-antenna and its pattern reconfigurability property effectively applicable for functional brain imaging applications.