Single Split Resonator Research Articles

CASSR based metamaterial tunable low pass filter

With the need for compact, discrete, and tunable passive devices in the upcoming wireless communication techniques, metamaterials have been proven to their incredible properties and have raised a new paradigm. The article discusses the possibility to design an electrically small metamaterial low pass filter (LPF) from a Complementary Asymmetric Single Split Resonator (CASSR) with a tunable pass-band for high-performance communication systems. The proposed CASSR filter on low-cost FR4 substrate of relative permittivity 4.4 and thickness 1.6 mm for a cut-off frequency of 1.12 GHz shows a roll-off rate of 159 dB/GHz. It is electrically small with a footprint area of 0.112λ × 0.112λ mm2 with ka = 0.70.

A square ring and single split resonator based wearable antenna for Microwave energy harvesting for IoT nodes

A wearable antenna utilising metamaterial radiating elements, which operates at two frequency bands, are presented in this paper. A closed-ring resonator and a single split-ring resonator of square shape have been used to provide dual resonance. The work develops a compact microstrip patch antenna having radiating patch dimensions of 24.8 × 24.8 mm2, that generates electromagnetic energy exhibiting dual band from 2.3 to 2.5 Giga Hertz (WiMAX, ISM) and 3.4 to 3.6 Giga Hertz (WiMAX band). This work provides relevant parametric analyses, such as free space, on-body, and antenna bending effects. Microstrip antenna is designed to be built on flexible dielectric substrate named Rogers RT-5880 Material with dielectric constant 2.2 and thickness of 0.787 mm. The design is validated by a comparison of numerical and actual antenna measurements. Between simulated and measured findings, good equivalence has been discovered. The fabricated antenna provides an impedance bandwidth of 1036 Mega Hertz in lower and 352 Mega Hertz in upper-frequency range, a gain of 2.7 dB,2.35 dB, the directivity of 3 dB, 2.9 dB, the radiation efficiency of 93.32%,88.21 % at 2.4 and 3.6 Giga Hertz respectively in free space condition. The results highlight the applicability of an energy efficient dual-band proposed antenna in wearable applications and microwave energy harvesting for IoT nodes within the ISM and WiMAX bands.

A simple electrically small microwave sensor based on complementary asymmetric single split resonator for dielectric characterization of solids and liquids

The article presents an asymmetric single split resonator (ASSR) unit cell, its resonant properties, and an electrically small microwave sensor employing the complementary asymmetric single split resonator (CASSR) structure with high quality factor (Q) on the FR4 substrate. The structure is compared with the conventional symmetric split ring resonator. The CASSR sensor designed and fabricated on a substrate of dielectric constant 4.4 and a thickness 1.6 mm has an electrically small size of 0.127λ0 × 0.127λ0 × 0.007λ0 at 1.27 GHz, which yields ka = 0.56 < 1 with low radiation efficiency. The properties and performance of the proposed CASSR for extracting the permittivity of both solid and liquid samples using amplitude and phase sensing in a simple lab-in-touch approach are validated with full-wave simulations and experimental results.

High Q-factor metasurfaces based on miniaturized asymmetric single split resonators

We introduce asymmetric single split rectangular resonators as bandstop metasurfaces, which exhibit very high Q-factors in combination with low passband losses and a small electrical footprint. The effect of the degree of asymmetry on the frequency response is thoroughly studied. Furthermore, complementary structures, which feature a bandpass behavior, were derived by applying Babinet’s principle and investigated with regards to their transmission characteristics. In future, asymmetric single split rectangular resonators could provide efficient unit cells for frequency selective surface devices, such as thin-film sensors or high performance filters.