Double-sided Split-ring Resonator Research Articles

The use of metamaterial type double-sided resonator structures in humidity and concentration sensing applications

In this study, the applications of ordinary double-sided split ring resonator (DSRR), double-sided L-type resonator (DLTR) and double-sided closed-cross-ring resonator (DCCR) structures in humidity sensing of chickpea powders and in concentration sensing of methanol-deionized water solutions are studied both in numerically and experimentally for five different samples in each case in microwave S- and X-bands. For the sensitivity analyses, the transmission spectra (i.e. |S21|) of the sensors are obtained by using rectangular hollow waveguide setups and the dependence of the resonance frequencies on the percentage humidity of chickpea powders or volume fraction of methanol in methanol-deionized water solutions have been recorded. The results show that the DLTR structure is more sensitive than DSRR in both sensing applications in both frequency bands under magnetic excitation. On the other hand DCCR has found to be more sensitive than DSRR for the humidity sensing of chickpea powders and DSRR has found to be more sensitive than DCCR for the concentration sensing of methanol-deionized water application under electrical with normal incidence. It is believed this study provides significant contributions to the sensor literature by introducing specially designed double-sided topologies (i.e. DLTR and DCCR) for two different applications, using special methodologies depending on the application, using two different excitations and two different frequency bands in the characterization.

Multi-functional metamaterial sensor based on a broad-side coupled SRR topology with a multi-layer substrate

This paper intends to demonstrate the feasibility of a miniaturized multi-purpose metamaterial sensor that can be effectively used for chemical, biological and pressure sensing in microwave and terahertz applications. This novel sensor design makes use of the double-sided split ring resonator (DSRR) topology that is modified to have an additional sensing medium sandwiched between two identical broadside coupled SRR unit cells. The resonance frequency of the resulting DSRR sensor shifts as the dielectric permittivity or thickness of this interlayer medium changes in response to variations in an environmental parameter such as temperature, humidity, density, concentration or pressure. As a proof of concept study, both numerical and experimental results are presented with very good agreement for a multi-functional miniaturized metamaterial sensor prototype operating in X-band. Simulations for three different real-life scenarios are also presented for this sensor topology to demonstrate a moisture sensor, a density sensor and a temperature sensor with very good sensitivities where the interlayer medium is occupied by sawdust, silica aerogel and seawater, respectively.

COMPARATIVE INVESTIGATION OF RESONANCE CHARACTERISTICS AND ELECTRICAL SIZE OF THE DOUBLE-SIDED SRR, BC-SRR AND CONVENTIONAL SRR TYPE METAMATERIALS FOR VARYING SUBSTRATE PARAMETERS

This paper introduces a planar µ-negative (MNG) metamaterial structure, called double-sided split ring resonator (DSRR), which combines the features of a conventional SRR and a broadside-coupled SRR (BC-SRR) to obtain much better miniaturization at microwave frequencies for a given physical cell size. In this study, electromagnetic transmission characteristics of DSRR, BC-SRR and conventional SRR are investigated in a comparative manner for varying values of substrate parameters which are thickness, the real part of relative permittivity and dielectric loss tangent. Simulation results have shown that magnetic resonance patterns of all these three structures are affected in a similar way from variations in permittivity and in loss tangent. However, changes in substrate thickness affect their resonance characteristics quite differently: In response to decreasing substrate thickness, resonance frequency of the SRR increases slowly while the bandwidth and the depth of its resonance curve do not change much. For the DSRR and BC- SRR structures, on the other hand, resonance frequency, half power bandwidth and the depth of resonance curve strongly decrease with decreasing substrate thickness. Among these three structures, all having the same unit cell dimensions, the newly suggested DSRR is found to reach the lowest resonance frequency, hence the smallest electrical size, which is a highly desired property not only for more effective medium approximation but also for miniaturization in RF design. The BC-SRR, on the other hand, provides the largest