Bandwidth Performance (bandwidth + performance)

Distribution by Scientific Domains


Selected Abstracts


Modeling and optimization of cylindrical antennas using the mode-expansion method and genetic algorithms

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 6 2005
Dawei Shen
Abstract For monopole antennas with cylindrically symmetric structures, a mode-expansion method is highly time efficient, which is a realistic approach for integrating function-optimization tools, such as genetic algorithms (GAs), in order to extract the best bandwidth property. In this article, a mode-expansion method is used to simulate the impedance characteristics of the cylindrical antennas. As examples, two new types of monopole antennas are presented, one of which possesses a two-step top-hat structure while the other has an annulus around the stem. After the modeling scheme is examined for convergence and data validity, the associated optimization problem, with dimensions as decision variables, structural limitations as linear constraints, and desired bandwidth performance as an objective function, is solved using GAs. The effects of the geometric parameters on the impedance characteristics are investigated in order to demonstrate the optimality of the calculated solutions. Two optimized practical antennas are designed based on our numerical studies. One has a broad bandwidth of 3 GHz while the other shows a dual-band property, which can satisfy the bandwidth requirements for both Bluetooth (2.45-GHz band) and WLAN (5-GHz band) systems. 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005. [source]


C-shaped ultra-wideband bandpass filter with WLAN notch band

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010
Pai-Yi Hsiao
Abstract A compact bandpass filter (BPF) embedded with 5.8 GHz wireless-LAN notch is presented for 3.1,10.6 GHz ultra-wideband (UWB) systems. The proposed UWB-BPF based on a defect-grounded structure is implemented with an FR4 board. Two open-loop resonators on the top layer provide a narrow notch band whose center frequency can be easily adjusted by varying the sizes of the open-loop. A simple C-shaped slot on the bottom ground layer is adopted to improve the bandwidth performance. The characteristics of UWB-BPF are analyzed and simulated using a circuit model of LC lump elements. The size of the filter is at least 34% less than those filters with the same specification. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1215,1218, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25153 [source]


A dual-band split-ring monopole antenna for WLAN applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2009
Siddik Cumhur Basaran
Abstract In this article, a novel dual-band microstrip monopole antenna based on split-ring elements is proposed for WLAN (2.4/5 GHz) applications. The antenna fed by a two-stage microstrip line has fairly small dimensions and provides 7.5 and 25.5% impedance bandwidth performance at the respective bands. Also, the antenna exhibits almost uniform radiation patterns at each frequency band. The measurement results of the fabricated antenna are in good agreement with the simulations. 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2685,2688, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24708 [source]


Magnetic loading of EBG AMC ground planes and ultrathin absorbers for improved bandwidth performance and reduced size

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2006
D. J. Kern
Abstract This paper demonstrates the advantages of magnetic loading within the substrate of an electromagnetic bandgap (EBG) surface. A conventional EBG surface has been shown to act as an artificial magnetic conductor over a narrow bandwidth. This paper demonstrates that by magnetic loading of the substrate, increased operating bandwidth is achieved for each resonant frequency. In addition, previous research has revealed that an ultrathin electromagnetic absorber design can be obtained by introducing loss into the frequency selective surface of an EBG absorber. It is now shown that a further reduction in thickness is possible by including a small amount of magnetic permeability within the dielectric substrate material. 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2468,2471, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21972 [source]