Rectangular split-ring resonators with single-split and two-splits under different excitations at microwave frequencies

In this work, transmission characteristics of rectangular split-ring resonators with single-split and two-splits are analyzed at microwave frequencies. The resonators are coupled with monopole antennas for excitation. The scattering parameters of the devices are investigated under different polarizations of E and H fields. The magnetic resonances induced by E and H fields are identified and the differences in the behavior of the resonators due to orientations of the fields are explained based on simulation and experimental results. The addition of the second split of the device is investigated considering different configurations of the excitation vectors. It is demonstrated that the single-split and the two-splits resonators exhibit identical transmission characteristics for a certain excitation configuration as verified with simulations and experiments. The presented resonators can effectively function as frequency selective media for varying excitation conditions

A micromachined freestanding terahertz absorber with an array of metallic patches

An array of square metallic patches on a thin suspended dielectric layer is introduced as an effective terahertz absorber. The suspended structure is placed on a metalized substrate and the device exhibits metamaterial behavior at specific frequencies determined by the size of the patches. It is feasible to place patches with different sizes in an array formation for a broadband absorber. In array configuration, individual elements induce distinct resonances yielding narrow band absorption regions. Design of the absorber is described using electromagnetic simulations. The absorber structure was fabricated on a silicon wafer using standard microfabrication techniques. The characteristics of the absorber were measured using a terahertz time domain spectroscope. The measured data match well the simulations indicating strong absorption peaks in a band of 0.5-2 THz

A Microwave Ring Resonator Based Glucose Sensor

A microwave ring resonator based glucose detecting biosensor incorporating glucose oxidase enzyme is presented. Sensor uses a split ring resonator as a transducer, where the sensing operation is done by the observation of shifts in its resonant frequency. Resonator was fabricated with basic fabrication techniques and the enzyme was immobilized via conductive polymer agent PEDOT:PSS. Experimentally observed redshift of resonant frequency of the sensor in response to different loading conditions are in agreement with simulation results and theoretical expectations. Sensor selectivity is confirmed with control experiments conducted with NaCl solutions. Experiments done with different glucose solution concentrations yielded a sensor sensitivity of 0.174MHz/mgml-1