- 标题
- 摘要
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Design and characterization of the double-layered defected ground structure transmission line with less radiation loss
摘要： A double-layered DGS transmission line is proposed with a smaller DGS size and less radiation loss. Changing the air boundary to a dielectric boundary reduces the effective electric length at the DGS aperture area. An equivalent circuit model is introduced to analyze the DGS transmission line and the resonator circuit designs. Due to the increase in the effective dielectric constant, the proposed structure can be realized with less sensitivity to metallic environments. From the experimental results, the proposed double-layered DGS can achieve a reduction of 90.1% in size and insensitivity at up to 5 mm of separation from the DGS aperture to the metallic plate.
关键词： equivalent circuit models,effective dielectric constants,radiation loss,size reduction,defected ground structures
更新于2025-09-23 15:23:52
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Suppression of radiation loss in high kinetic inductance superconducting co-planar waveguides
摘要： We present a lab-on-chip technique to measure the very low losses in superconducting transmission lines at (sub-) mm wavelengths. The chips consist of a 100 nm-thick NbTiN Co-planar Waveguide (CPW) Fabry–P(cid:2)erot (FP) resonator, coupled, on one side, to an antenna and, on the other side, to a Microwave Kinetic Inductance detector. Using a single frequency radiation source allows us to measure the frequency response of the FP around 350 GHz and deduce its losses. We show that the loss is dominated by radiation loss inside the CPW line that forms the FP and that it decreases with the decreasing linewidth and increasing kinetic inductance as expected. The results can be quantitatively understood using SONNET simulations. The lowest loss is observed for a CPW with a total width of 6 lm and corresponds to a Q-factor of (cid:2)15 000.
关键词： radiation loss,Fabry–P(cid:2)erot resonator,co-planar waveguides,superconducting transmission lines,kinetic inductance
更新于2025-09-23 15:21:01
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A novel wideband bandpass filter based on CSRRa??loaded substrate integrated folded waveguide
摘要： A novel wideband bandpass filter based on folded substrate integrated waveguide (FSIW) is presented in the article. Five square complementary split-ring resonators (CSRRs) are etched in the middle layer of the FSIW. By adjusting the physical size of the CSRR structure, the resonant frequency of the CSRRs can be tuned at the same time and the stopband performance can be changed. As transverse electromagnetic (TEM) mode can be transmitted in the stripline, FSIW excited by stripline shows wider passband than that excited by microstrip line directly. To achieve perfect impedance matching, two microstrip lines to stripline transitions are added in two ports of the filter. The proposed bandpass filter exhibits compact size, high selectivity, good stopband rejection, lower radiation loss, and wideband performances. The measured results show that the fractional bandwidth of the filter is about 35.5%. The measured return loss is better than 15 dB from 4.84 GHz to 6.90 GHz, and the insertion loss is less than 1.2 dB. The comparison between the simulated results and the measured ones validate the possibility of the technology that combines the FSIW and CSRR.
关键词： radiation loss,compact size,folded substrate integrated waveguide,bandpass filter,complementary split-ring resonators (CSRRs)
更新于2025-09-19 17:13:59
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Two-Dimensional Heterojunction Photovoltaic Cells with Low Spontaneous-Radiation Loss and High Efficiency Limit
摘要： This work presents theoretical investigations on the spontaneous-radiation loss of two-dimensional van der Waals heterojunction photovoltaic cells (2D-PVcs) combined with an interference-based light-trapping structure. We find that 2D-PVcs possess much lower spontaneous radiation loss, since the solid angle of the spontaneous radiation is a magnitude smaller than that in traditional PVcs. The efficiency limit of a 2D-PVc can be 10% larger than that of a traditional PVc. Furthermore, we demonstrate that the spontaneous-radiation loss can be further reduced by introducing only a weak light-concentrating system, approaching the efficiency limit of traditional PVcs under perfect focus. In a trapped structure, the smaller the light absorption coefficients of the photovoltaic cells, the higher are the efficiency limits that are achieved. Finally, the spontaneous-radiation loss increases as the battery thickness increases, indicating that the 2D-PVc has the lowest spontaneous emission loss because of its extremely low thickness.
关键词： photovoltaic cells,two-dimensional heterojunction,spontaneous-radiation loss,light-trapping structure,efficiency limit
更新于2025-09-11 14:15:04