This article presents a novel circular polarized (CP) aperture coupled stack antenna for wireless local area network and worldwide interoperability for microwave access dual-band systems. The compact stack antenna consisted of square fractal patch, aperture couple, feed line and the perturbation. The square patch is constructed with the complementary Minkowski-island-based fractal geometry. By way of adjusting the relevant parameters, we can obtain the dual-band responses at 3.5 and 5.25 GHz respectively. The CP of each band are presented. The measured 10 dB return loss impedance bandwidth are 270 MHz (7.5%) for 3.5 GHz band and 450 MHz (8.6%) for 5.25 GHz band. The 3 dB axial ratio bandwidths for each bands are 1.4 and 0.76%, the polarization of radiation patterns are both left-hand CP, and the antenna power gain are 2.84-3.1 and 0.16-2.2, dBic respectively. The proposed antenna is successfully simulated and measured with frequency responses, radiation patterns and current distributions. V C 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:130-138, 2014.

This article presents a novel triband circular/elliptical polarized single‐feed circular slot antenna for wireless local area network and worldwide interoperability for microwave access systems. The proposed antenna is constructed with two asymmetrical C‐shaped strips facing in opposite directions and embedded in the circular slot and the enhanced feed strip of coplanar waveguide. By way of adjusting the relevant parameters, we can obtain the triband responses at 2.4, 3.5 and 5.25 GHz, respectively. The circular/elliptical polarizations (CP/EP) of each band are presented. The measured −10 dB return loss impedance bandwidth are 270 MHz (11.1%) for 2.4 GHz band, 380 MHz (11.0%) for 3.5 GHz band, and 290 MHz (5.6%) for 5.25 GHz band. The −3 dB axial ratio bandwidth for each band are 10.4, 5.7, and 2.9%, the polarization of radiation patterns are right‐hand CP, right‐hand EP, and left‐hand CP and the antenna gain are 3.2, 4.3, and 5.2 dBic, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:272–278, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27300

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The coplanar waveguide‐fed planar slot antenna with the embedded ring‐type strip for dual‐frequency operation is investigated and experimentally explores in this letter. The prototype, which is implemented on the 0.8‐mm FR‐4 substrate with εr = 4.4, indicates that the embedded ring‐type strip offers extended path for the electric current flow, achieving 45.1% size reduction of the fundamental resonant mode. The ratio of the center frequencies of the first two resonant bands can be tuned within a range wider than 1.81 by increasing the radius and line width of ring‐type strip. Furthermore, the fundamental resonant mode can be shifted to the higher frequency to combine with the second resonant mode of the circular slot, indicating the wideband operation with the bandwidth of 1332 MHz (40.5%). © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2882–2887, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26370

This paper presents a novel dual-band circularly polarized CPW-fed circular slot antenna with two open-ground rings. The proposed antenna is constructed with two opened-ground rings facing in opposite directions and embedded in the circular slot and the enhanced feed strip of CPW. By way of adjusting the relevant parameters, we can obtain the dualband at 1.57 GHz and 2.46 GHz respectively. A smaller frequency ratio of 1.56 is presented. The measured −10 dB return loss impedance bandwidth are 380 MHz (24.68%) for 1.57 GHz band and 210 MHz (8.33%) for 2.46 GHz band. The measured −3 dB axial ratio bandwidth for 1.57 GHz and 2.46 GHz bands are 13.38% and 8.13%, the polarization of radiation patterns are RHCP and LHCP for each band and the antenna gain are 3.72 and 3.21 dBic respectively.