Compact Dual-Band Bandpass Filter Based on Quarter Wavelength Stepped Impedance Resonators

Year: 2016 Volume: 10 Issue: 4 517 - 520 Pages

• Authors:
• Yu-Fu Chen
• Zih-Jyun Dai
• Chen-Te Chiu
• Shiue-Chen Chiou
• Yung-Wei Chen
• Yu-Ming Lin
• Kuan-Yu Chen
• Hung-Wei Wu
• Hsin-Ying Lee
• Yan-Kuin Su
• Shoou-Jinn Chang

Abstract: This paper presents a compact dual-band bandpass filter that involves using the quarter wavelength stepped impedance resonators (SIRs) for achieving simultaneously compact circuit size and good dual-band performance. The filter is designed at 2.4 / 3.5 GHz and constructed by two pairs of quarter wavelength SIRs and source-load lines. By properly tuning the impedance ratio, length ratio and radius of via hole of the SIRs, dual-passbands performance can be easily determined. To improve the passband selectivity, the use of source-load lines is to increase coupling energy between the resonators. The filter is showing simple configuration, effective design method and small circuit size. The measured results are in good agreement with the simulation results.

• Keywords:
• Dual-band
• bandpass filter
• stepped impedance resonators
• SIR.

Efficiency Improvements of GaAs-based Solar Cells by Hydrothermally-deposited ZnO Nanostructure Array

Year: 2011 Volume: 5 Issue: 7 609 - 613 Pages

• Authors:
• Chun-Yuan Huang
• Chiao-Yang Cheng
• Chun-Yem Huang
• Yan-Kuin Su
• James Chin-Lung Fang

Abstract: ZnO nanostructures including nanowires, nanorods, and nanoneedles were successfully deposited on GaAs substrates, respectively, by simple two-step chemical method for the first time. A ZnO seed layer was firstly pre-coated on the O2-plasma treated substrate by sol-gel process, followed by the nucleation of ZnO nanostructures through hydrothermal synthesis. Nanostructures with different average diameter (15-250 nm), length (0.9-1.8 μm), density (0.9-16×109 cm-2) were obtained via adjusting the growth time and concentration of precursors. From the reflectivity spectra, we concluded ordered and taper nanostructures were preferential for photovoltaic applications. ZnO nanoneedles with an average diameter of 106 nm, a moderate length of 2.4 μm, and the density of 7.2×109 cm-2 could be synthesized in the concentration of 0.04 M for 18 h. Integrated with the nanoneedle array, the power conversion efficiency of single junction solar cell was increased from 7.3 to 12.2%, corresponding to a 67% improvement.

• Keywords:
• Anti-reflection
• Chemical synthesis
• Solar cells
• ZnO nanostructures.