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Antenna Performance (antenna + performance)
Selected AbstractsUltra-wideband coplanar boat microstrip patch with modified ground plane by using electromagnetic band-gap structure for wireless communicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2010Dalia N. Elsheakh Abstract A new antenna structure using triangular patch alongside a small trapezoidal shape ground plane with proximity fed is proposed in this article. The proposed antenna design provides a bandwidth in the range from 2 < 35 GHz with band discontinuities. Improvement is done in antenna performance by using electromagnetic band-gap (EBG) structure. First, dumb-bell shapes as 2D-EBG are etched in the feeding line. Second, embedded spiral artificial magnetic conductor with four arms to introduce sufficient inductive impedance is done. The resultant bandwidth increases to three times than the original bandwidth and reduces the antenna size as well as enhancing the antenna gain. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1159,1164, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25129 [source] An inkjet-printed inverted-F antenna for 2.4-GHz wrist applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2009Vamsi K. Palukuru Abstract In this article, an inkjet-printed inverted-F antenna suitable for a watch-type wireless communication device is presented. The antenna and covering the 2.4 WLAN band (2.4,2.484 GHz) has thickness (2 mm3) and size (40 × 25 mm2). The performance of the printed antenna is experimentally studied and compared with a reference antenna made of Rogers copper laminate. The effect of inkjet-printed layer thickness on the antenna performance is presented. In addition, the impact of the user's hand proximity on the antenna performance is studied experimentally. The results showed that the total antenna efficiency increases by 13% and 27% with an increase of 1.5 ,m in printed layer thickness and a user's hand to antenna distance of 12.5 mm, respectively. The shape of the radiation pattern of the antenna is distorted due to the proximity of the user's hand. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2936,2938, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24777 [source] Study of a band-notched double printed dipole antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008Fa-Jia Wang Abstract In this article, a double-printed dipole antenna with band-notched function for UWB applications is proposed and investigated. The band-notched characteristic is achieved by inserting two U-shaped slots on the dipole. Experimental and numerical results show that the proposed antenna meets the requirement of 3.1,10.6 GHz UWB systems with VSWR < 2, while avoiding the interference with the 5 GHz WLAN band. Transmitting antenna transfer function, receiving antenna transfer function, and antenna system function are used to describe the antenna performance. The impulse responses in time domain were calculated using inverse Fourier transform. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2986,2989, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23816 [source] 5.8 GHz orientation-specific extruded-fin heatsink antennas for 3D RF system integrationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008Lance Covert Abstract In high-power RF transmitter applications, the heatsink can be used as an antenna for improved antenna performance and increased integration. Extruded-fin heatsink antennas designed at 5.8 GHz are orientation-specific when the heatsink base replaces the patch of a patch antenna. In this case, the orientation of the fins with respect to the patch edges plays a significant role in the antenna performance and must be considered. The results show that the heatsink antenna using a lossy, low-cost FR4 substrate increases the bandwidth from 3.1 to 17.6% and radiation efficiency from 62 to 87% compared with the patch antenna on the same substrate. Also, the orientation has a significant effect on the directivity, gain, and radiation pattern. By combining two functions into one structure, the component count in a system is reduced and the antenna performance can be improved. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1826,1831, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23478 [source] RFID tag antenna using two-shorted microstrip patches mountable on metallic objectsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2007Byunggil Yu Abstract A novel UHF band RFID tag antenna, which can be effectively mounted on metallic objects, is presented. Using the inductively coupled feeding technique, the proposed antenna consists of two symmetric shorted radiating elements and feeding loop. The feeding loop is excited so that the currents on the radiating elements are out of phase with the equal amplitude. The proposed tag antenna gives smaller variation of the antenna performance than that of conventional tag antennas when the tag is mounted on the various sizes of the metallic objects. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 414,416, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22159 [source] Short helical antenna with extremely small pitch angleMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2007Ze-Hai Wu Abstract A 2-turn helical antenna with small pitch angle between 0.6° and 3° has been studied as a radiation element of circular polarization waves in this article. The antenna with pitch angle 2° exhibits a 3-dB axial ratio bandwidth of 9.8%, and the optimal axial ratio of 0.1 dB. When the pitch angle decreases to 0.6°, the 3-dB axial ratio bandwidth and the best axial ratio are 5% and 0.15 dB, respectively. Variation of on-axis axial ratio as a function of the straight wire height h has been computed, and the current along the helix is also given. Experimental verification of the antenna performance is presented. The antenna with low profile and high polarization purity characteristics is suitable for application of array antenna. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 17,19, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22054 [source] SAR of internal antenna in mobile-phone applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2005K. H. Chan Abstract This paper presents an investigation of the effect of the internal antenna on the specific absorption rate (SAR), and the effect of the presence of a human head at close proximity to a mobile phone upon the antenna performance in mobile-phone applications. Both the experimental measurement and numerical simulation of the SAR values and the antenna performance parameters of a typical internal antenna are presented. The results indicate that the far-field radiations of the internal antenna can be reduced by 3 dB with the presence of human head. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45:286,290, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20797 [source] Narrow flat metal-plate antenna for dual-band WLAN operationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2003Chi-Yin Fang Abstract A novel dual-band antenna made of a narrow, rectangular, flat metal plate for wireless local area network (WLAN) operation in the 2.4- and 5.2-GHz bands is presented. The antenna comprises a larger radiating arm, a smaller radiating arm, and a shorting portion. The larger and smaller radiating arms control a lower resonant mode at about 2.4 GHz and an upper resonant mode at about 5.2 GHz, respectively, and are connected to each other through the shorting portion. The antenna is easily excited by using a 50, mini coaxial line and shows good antenna performance. The proposed antenna design is described and experimentally studied. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 398,400, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11072 [source] Probe-fed microstrip antennas loaded with very high-permittivity ceramicsINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2006Y. Hwang Abstract This article reports the feasibility study of miniaturizing probe-fed microstrip patch antennas by dielectric loading. The loading materials are barium tetratitanate ceramics of very high dielectric constant (,r = 38, 80). It is shown that, simply through loading, the antenna sizes are greatly reduced; however, the antenna performances are deteriorated. For instance, the antenna gain becomes lower. Then enhancement of the antenna performances follows. A substrate,superstrate structure is used to recover the gain. Both the experiments and the finite-difference time-domain (FDTD) simulations demonstrate that the gain and impedance bandwidth can be retrieved such that they are comparable to those of conventional microstrip antennas loaded with low permittivity materials (,r < 3). © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [source] Very small size printed monopole with embedded chip inductor for 2.4/5.2/5.8 GHz WLAN laptop computer antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010Ting-Wei Kang Abstract A very small size planar two-strip monopole printed on a thin (0.4 mm) FR4 substrate for 2.4/5.2/5.8 GHz triple-band WLAN operation in the laptop computer is presented. With the aid of an embedded chip inductor of 5.6 nH in the longer strip of the printed monopole, a much reduced strip length for obtaining the resonant mode at about 2.4 GHz is obtained, thereby leading to a much reduced size of the antenna for the desired WLAN operation. When the antenna is mounted along the top edge of the display ground, it shows a height of 9 mm and a length of 6 mm only, which is about the smallest among the triple-band WLAN laptop computer antennas that have been reported. Details of the proposed antenna are described. Results of the fabricated prototype, including the user's hand effects on the antenna performances, are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 171,177, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24843 [source] Broadband coaxial antenna for WiMAX access-point applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2006Kin-Lu Wong Abstract A broadband coaxial antenna mainly comprising an upper square cylindrical plate and a lower square cylindrical ground is presented. The antenna functions like a two-wire dipole antenna, and furthermore provides a wide operating bandwidth of about 4 GHz (about 1.9 to 5.9 GHz in the study), making it very promising for application in Worldwide Interoperability for Microwave Access Forum (WiMAX) access points. The antenna has been successfully implemented, and experimental results are presented. The effects of the lower square cylindrical ground on the antenna performances are also analyzed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 641,644, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21432 [source] A conical-pattern annular-ring microstrip antenna with a photonic bandgap ground planeMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2001Shun-Yun Lin Abstract A probe-fed annular-ring microstrip antenna with a photonic bandgap (PBG) ground plane operating in the higher order mode of TM21 for conical-pattern radiation is experimentally demonstrated. The antenna studied is printed on a thin FR4 substrate (relative permittivity 4.4) and, owing to the PBG ground plane used, significant improvements in the antenna performances are observed. The obtained impedance bandwidth is doubled, and the antenna gain is enhanced by about 7 dBi. Details of the experimental results are presented and discussed. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 159,161, 2001. [source] | ||||||||||