Quad Band Metamaterial Inspired Planar Sensor for Dispersive Material Testing

Novel design of metamaterial inspired quad band planar microwave sensor is presented in this work. Proposed design topology consists of two pairs of concentric single ring complementary split ring resonators (SCSRR), etched on the ground plane of microstrip line. To design the quad band sensor, orientation of concentric SCSRRs with each other is first studied and it is found that in line orientation of SCSRRs provides minimum coupling between them. The proposed configuration of placing two inline SCSRRs with optimized interspacing between these two concentric SCSRRs facilitates the design of compact quad band sensor. Design and optimization of proposed quad band sensor are performed using the 3D electromagnetic solver, the CST-MWS. The proposed quad band sensor is designed to work in the ISM and WiMAX frequency bands (1.87 GHz, 2.46 GHz, 3.49 GHz and 4.34 GHz). The designed quad band sensor is fabricated on a FR-4 substrate and the measurements for various dispersive liquids are performed with the vector network analyzer. A close agreement between the simulated and measured frequency response of the device under both loaded and unloaded conditions is observed. The proposed design methodology is suitable developing compact sensors which can be very useful for various applications in the RF and microwave frequency region,