A cylindrical wideband slotted patch antenna loaded with Frequency Selective Surface for MRI applications

A novel cylindrical antenna of a miniaturized printed circuitry is invented for Microwave Radiology Imaging (MRI) applications. Folded metamaterial structures based a Frequency Selective Surface (FSS) on a cylindrical profile is conducted in the design methodology. The combination of MRI systems with Ultra-Wide Band (UWB) radars for improving the functional diagnosis and imaging process has been proposed recently. Moreover, MRI systems call for a directive beam as much as narrow about 5 dBi with a fixed direction toward the broadside over the entire frequency range of interest to suit the mechanical steering principles. Therefore, a Slotted Triangular Flared (STF) patch excited with a 50 Ω exponential curved transmission line transformer centered between two matching circuit tuners is proposed. The patch structure is mounted on a Teflon substrate backed with a Partial Defected Ground (PDG) plane. An in-phase reflector array based on a cylindrical FSS is introduced to the antenna design to enhance the bandwidth and the front to back ratio. The antenna performance is examined using CST MWS commercial software package based on the Finite Integration Technique (FIT) in both Time Domain (TD) and Frequency Domain (FD) solvers. Moreover, the antenna dimensions are modified through a parametric study to arrive to the optimal performance in terms of antenna bandwidth with minimum size. The optimal antenna dimensions are realized to be 32 mm in height with a diameter of 20 mm. It is found the proposed antenna operates over the frequency range from 7.8 GHz up to 15 GHz with a bore-sight gain varies from 2 dBi up to 6 dBi. Finally, the obtained results are re-evaluated using Finite Element Method (FEM) based on HFSS formulation. An excellent matching is observed between the evaluated results from both software packages.