Dielectric loss

About: Dielectric loss is a research topic. Over the lifetime, 20296 publications have been published within this topic receiving 349254 citations.

Dielectric properties of mixed Li–Ni–Cd ferrites

Abstract: Ferrites with the general formula Li0.5Ni0.75−x/2Cdx/2Fe2O4 (where x = 0, 0.1, 0.3, 0.5, 0.7 and 0.9) were prepared by the standard double sintering ceramic method. X-ray diffraction analysis confirmed the single phase spinel structure of the samples. The variation of saturation magnetization (Ms) was studied as a function of Cd content. The dielectric constant (e') and dielectric loss tangent (tanδ) were measured at room temperature as a function of frequency in the range 100 Hz–1 MHz. These parameters decrease with increasing frequency for all of the samples. The compositional variation of e' and ρDC show an inverse trend of variation with each other.

Nd doping of bismuth ferrite to tune electromagnetic properties and increase microwave absorption by magnetic–dielectric synergy

Abstract: Simultaneously achieving tunable electromagnetic parameters and strong absorption capacity in a single material is still a great challenge. Here, we present Nd doped BiFeO3 with electromagnetic matching, which exhibits tunable electromagnetic properties and high-performance microwave absorption. The experimental and calculated results demonstrate that Nd doping generates the ordered domain structure and changes the coupling states of electrons, which induce difficult polarization rotation and strong natural ferromagnetic resonance, leading to the decrease of dielectric loss and the increase of magnetic loss with increasing Nd concentration. The electromagnetic parameters are tuned from mismatching to matching, and the microwave absorption is improved. Bi0.8Nd0.2FeO3 exhibits a remarkable reflection loss (RL) of −42 dB and bandwidth (RL ≤ −10 dB) which covers nearly three quarters of the X-band at a thickness from 1.9 to 2.1 mm. This work highlights the applications of BFO as a high-performance microwave absorber and opens up a promising feasible route to the development of microwave absorbers in imaging, healthcare, information safety and military fields.

Characterization of thin film microstrip lines on polyimide

Abstract: This paper presents an in depth characterization of thin film microstrip (TFMS) lines fabricated on Dupont PI-2611 polyimide. Measured attenuation and effective dielectric constant is presented for TFMS lines with thicknesses from 2.45-7.4 /spl mu/m and line widths from 5-34.4 /spl mu/m over the frequency range of 1-110 GHz. The attenuation is separated into conductor and dielectric losses to determine the loss tangent of Dupont PI-2611 polyimide over the microwave frequency range. In addition, the measured characteristics are compared to closed form equations for /spl alpha/ and /spl epsiv//sub eff/ from the literature. Based on the comparisons, recommendations for the best closed form design equations for TFMS are made.