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In this paper, an all-dielectric metastructure-based high-contrast refractive index sensor is proposed. This structure can be utilized to detect various concentrations of glycerol-water mixtures by evaluating transmission spectral lines and resonant wavelength shifts related with liquid concentration detection. The experimental and calculated results of the developed sensor structure are able to excite three resonance peaks, demonstrating that the structure is capable of reaching excellent sensing capabilities. It has been established that this work has the potential to be useful in medical and biological detection; this is of great scientific and practical significance.

This paper presents an ultra-wideband (UWB) high temperature superconducting (HTS) bandpass filter (BPF) based on a ring resonator loaded with a pair of symmetrical cross-shaped steppedimpedance open stubs. The main advantages are that two transmission zeros are introduced to improve passband selectivity, and high mode suppression is achieved by adjusting the impedance ratio of the cross-shaped stubs and using a pair of parallel-coupled lines. The filter is designed on double-sided YBCO/MgO/YBCO HTS films with a thickness of 0.5 mm and dielectric constant of 9.8. At 77 K, the measured 3-dB bandwidth of the filter covers 1.63 GHz ∼ 6.03 GHz. Due to the use of superconducting material, the insertion loss at the center frequency of 3.83 GHz is 0.12 dB, and the rejection is greater than 36 dB in the lower stopband, and the upper stopband with 20 dB attenuation level is extended to at least 8.5 GHz.