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ABSTRACT A wideband circularly polarized (CP) antenna with high gain is proposed. The circular polarization performance is obtained by two pairs of orthogonal bowtie dipoles with a coaxial balun feed and a broadband 90° hybrid feed network. Particularly, a design of rectangular ring with eight shorted posts is added around the bowtie dipoles, which can obtain a high gain. To further improve the gain of the novel antenna, a circular ring is placed around the rectangular ring on the same plane. With such an arrangement, the proposed antenna delivers a higher gain than that of the conventional dual-fed type CP antenna. The measured results show that the proposed antenna can achieve a measured impedance bandwidth for VSWR ≤ 1.5 of 61.5% and a 3-dB axial ratio bandwidth of 66.7%. The antenna has a stable peak CP gain better than 10.3 dBi ranging from 1.1 to 1.6 GHz. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1274-1277, 2014 [ABSTRACT FROM AUTHOR]

ABSTRACT The wideband performance of a bowtie antenna with Γ-shaped strip feed and tuning stubs is presented. Besides two folded elements connecting the patches of the bowtie dipole for a compact dimension, the Γ-shaped strip feed structure and the four tuning stubs to effectively improve the impendence matching can be used for bandwidth enhancement. A wideband impedance characteristics of about 58.6% for VSWR ≤ 1.5 ranging from 1.58-2.89 GHz is obtained and the stable peak gain of around 9 dBi, unidirectional radiation patterns and low cross-polarization over the whole operating band are also achieved. It is very suitable for the recent wireless communication services for the indoor-base station such as 3G, WiFi, WiMax, Bluetooth, and LTE/2.5 applications, and so on. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2145-2149, 2013 [ABSTRACT FROM AUTHOR]

A novel miniaturized dual-band monopole antenna loaded with two types of loops is presented. The split loop is loaded at the center of the monopole for dual-band operation and the rectangular loop loaded at the top is for miniaturization. The novel miniaturization technique is used as a self resonant topology. The monopole below its resonant frequency is known to possess a capacitive reactance and the loop below its resonant frequency has an inductive reactance. So an inductive loop is used to match a below-resonant monopole for miniaturization. As an example of this principle, a miniaturized dual-band antenna prototype for WLAN applications is designed, fabricated, and tested. Measured results show that the antenna offers higher gains and better efficiencies than the unloaded monopole. The radiation patterns are seen to be unaffected by the presence of the top loaded loop. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1236-1239, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26784 [ABSTRACT FROM AUTHOR]

A wideband circularly polarized antenna with Γ-shaped feed is presented.The proposed antenna is formed by two shorted bowtie patch antennas and two L-shaped electric dipoles. It can achieve a measured impedance bandwidth for voltage standing wave ratio (VSWR) ≤ 1.5 of 52% and a 3-dB axial ratio bandwidth of 55%. For the entire half-power beamwidth, the axial ratio can be kept below 3 dB. A prototype has been fabricated and tested, and the experimental results validate the design procedure. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:153-156, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26503 [ABSTRACT FROM AUTHOR]

A dual-resonant patch antenna applicable to active radio frequency identification (RFID) tags is designed. The designed antenna has been skillfully integrated with the active RFID tag circuit. The antenna consists of two parts. One part comprises stacked shorted patches and a ground plane. The other part is an active tag circuit mounted on the bottom of the antenna. The measurement results reveal that the antenna has the return loss less than -10 dB within the bandwidth of 42 MHz (from 911 to 953 MHz), which totally covers the 5 MHz bandwidth from 920 to 925 MHz (The band is also allowed for passive RFID) requirement for active RFID in China. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1280-1284, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26000 [ABSTRACT FROM AUTHOR]