the antenna electrical length due to the mobile case. As shown in the Figure 5, because WLAN frequency band can be controlled easily by C w1 , the surrounding environment is considered and it can be easily optimized. Figure 9 shows the measured radiation patterns at 2.45, 3.2, 4.0, and 4.7 GHz. The radiation patterns are omni-directional pattern with some nulls and the shapes of the patterns are almost unchanged over the UWB frequency band. Figure 10 shows the measured antenna gain of the proposed chip antenna. As can be seen from the figure, the peak gain of the dual-band chip antenna varies from 3.83 to 5.41 dBi over the operating frequency range and the antenna peak gain variation is 1.58 dBi.
CONCLUSIONSA novel dual-band chip antenna has designed, fabricated, and characterized for WLAN/UWB applications. The proposed antenna covers the lower UWB band (3.1-4.8 GHz) and WLAN band (2.45 GHz). The effects of the antenna geometry on the VSWRs were presented. The WLAN/UWB bands can be adjusted by changing the geometry of the C w1 and C c1 . Also we have examined the effect of the various environments. The proposed antenna has omni-directional pattern with some nulls and stable gain over the frequency band, though it has simple structure and very compact size. Thus, the proposed dual-band chip antenna is suitable for WLAN/UWB communication applications. ACKNOWLEDGMENTS This work was supported by the second stage of BK21. ABSTRACT: A compact size planar microstrip-fed monopole antenna designed for mobile handset applications is proposed. To operate at global system for mobile communication (GSM)/global positioning system/digital communication system/personal communication system/ universal mobile telecommunications system and 2.4-GHz wireless localarea network bands, a hybrid technique of joining the horizontal section of a T-monopole to an open-loop back coupling strip and loading a pair of monopole slot into the ground plane is used. Two operating bands are observed (along 3:1 VSWR) with the lower band covering only the GSM application, while the wide upper operating band covers the remaining applications. The effects on the antenna performances by tuning the various vital parameters have also been studied. V C 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:910-915, 2011; View this article online at wileyonlinelibrary.com.ABSTRACT: The article concerns the experimental validation of two techniques for compensating the probe positioning errors in a nearfield-far-field transformation with cylindrical scan using a nonredundant number of measurements. The former uses the singular value decomposition method and can be applied when the irregularly acquired samples lie on nonuniform rings, thus allowing to reduce the starting two-dimensional problem into two independent one-dimensional ones. The latter, based on an iterative technique, can be employed also when the previous hypothesis does not hold but requires the existence of a one-to-one correspondence, associating at each uniform sampling point the nearest ...
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