A long-range surface plasmon resonance (LRSPR) sensor based on dielectric/silver-coated hollow fiber (HF) is proposed. It can detect the refractive index (RI) of sensed liquid filled in the hollow core of the sensor. A HF LRSPR sensor with 90-nm-thick silver layer and 260-nm-thick OC300 layer is fabricated. Experiments are taken to evaluate the performance of the sensor by measuring the transmission spectra. Theoretical analysis based on a ray model is also taken, and the results agree well with the experimental results. The proposed sensor has similar sensitivity but much smaller SPR dip width than the silver-coated HF SPR sensor. Thus figure of merit of the sensor is enhanced approximately five times. The stability of the sensor is also improved because the dielectric layer acts as a protection layer for the damageable silver layer.

Magneto-dielectric materials with matched permeability and permittivity are promising candidates as loading materials to reduce the physical dimensions of low-frequency antennas. In this study, NiCuZn ferrites were prepared by both the traditional final-stage sintering process and the two-step sintering process to obtain the magneto-dielectric materials. It was found that the samples sintered by the two-step sintering process tended to obtain microstructure with dense, homogeneous, and small average grain size, which was favorable to obtain low magnetic and dielectric losses. The sample sintered by the two-step sintering process with high temperature 950 °C and holding temperature 900 °C could obtain almost equal permeability and permittivity of around 11.8. And the magnetic and dielectric loss tangents were lower than 0.015 in a frequency range from 10 to 100 MHz. These properties make the material useful to the design of miniaturized antennas.