Low-Profile CO-CSRR and EBG Loaded Tri-Quarter Circular Patch EWB MIMO Antenna With Multiple Notch Bands

A novel and miniaturized design featuring a Co-directional Complementary Split Ring Resonator (CO-CSRR) loaded Tri-Quarter Circular (TQC) Extremely Wideband (EWB) Multiple-Input Multiple-Output (MIMO) antenna has been developed and simulated. This proposed antenna demonstrates high isolation and exhibits multiple notch characteristics. The configuration consists of two TQC patches positioned adjacent to each other with a common partial ground plane (PGP), achieving an Extremely Wideband (EWB) capability of 85.8 GHz. Additionally, two elliptical CO-CSRRs are etched on the TQC elements to introduce dual-notch characteristics in the X-band and Ku-band. The integration of two Electromagnetic Band Gap (EBG) structures on either side of the microstrip feedline facilitates the creation of notch frequency ranges at Q-band downlink and V-band. To enhance isolation, a slotted meandering strip is extruded to the PGP. This design primarily focuses on achieving EWB with a compact size and reduced complexity. The overall physical volume of the proposed design is $2.74~\lambda _{o} {\times } 4.83~\lambda _{o} {\times } 0.25~\lambda _{o}$ , achieved a maximum $|S_{11}|$ of 30.82 dB at a frequency of 17.58 GHz. The antenna’s performance has been thoroughly evaluated in terms of radiation pattern, isolation, Total Active Reflection Coefficient (TARC), Envelope Correlation Coefficient (ECC), Diversity Gain (DG), Gain, and Efficiency. Stable gain and Group Delay (GD) of less than 0.2 ns for the entire Extremely Wideband (EWB) range have been achieved, with lower gain observed at the notch bands.