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The dual‐band circular slot antenna utilizing the embedded arc‐shaped metallic strip for the circularly polarized (CP) and linearly polarized (LP) operations is presented in this letter. The experimental results show that the resonant frequency of low‐band for CP mode is utilized the protruded arc‐shaped metallic strip, which extends current route to make the fundamental resonant mode shifted to the lower frequency band. The high‐band for LP mode, which has the similar current distribution to that of the fundamental mode of the conventional circular slot, is employed the first‐higher order resonant mode of the circular slot. Two measured input impedance bandwidths of the proposed design are 23.2% and 18.8%, respectively, and the measured bandwidth of low‐band with an axial ratio (AR) of less than 3.0 dB is 14.5%. The operating bands show the broadside radiation patterns with 1.7–2.7 dBic CP gain and the peak antenna gain of 3.6–4.3 dBi, respectively. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2717–2721, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25562

Abstract-A thin dipole antenna is a well-known antenna with linearly polarized wave operation. In this work, a wide-strip dipole antenna is proposed for circularly polarized wave operations. To obtain circularly polarized (CP) wave operations, there are two conditions to be satisfied. One is that the antenna must have two degenerated orthogonal modes with different resonant frequencies. The other is that the phase difference of two orthogonal modes is 90 degrees. To match the first condition, the slab width W is tuned to generate current distributions directed in two different directions. In addition, the second condition is matched by asymmetric feeding point by adjusting the overlapped square width C. The parametric study is completed by the Ansoft HFSS simulator. Simulated results reveal that the CP wave is mainly influenced by the slab width W . The influences of the parameters C and d on the performances of the proposed antenna are also investigated in this paper. Taking −8 dB as reference, there are two working bands for this proposed antenna and the measured center frequencies are 0.66 GHz and 2.04 GHz, respectively, and the corresponding bandwidths are 0.27 GHz (40%) and 1.78 GHz (87%), respectively. In addition, the measured center frequencies and bandwidths of the axial ratio are 1.94 GHz and 0.53 GHz (27%), respectively.Corresponding author: L.-P. Chi (cp531220@ms23.hinet.net). 70Chi et al.

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.

By means of novel packaged-structure design, a temperature independent differential pressure sensor based on fiber Bragg gratings with high sensitivity is experimentally demonstrated. The differential pressure sensitivity of the sensor can reach to 821.87nm/MPa. This device can also be used for simultaneous measurement of temperature and differential pressure, which is suitable for applications involving measurement of liquid level, liquid density or specific gravity detection.

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

A novel design of fractal monopole‐like antenna with series Hilbert‐curve configuration is proposed for 2.45/5.35 GHz dual‐band and circular polarization applications in this article. The compact fractal antenna consists of five series Hilbert‐curve and the monopole couplings, and exhibits the desired dual‐band 2.45 GHz (BW = 85 MHz, 3.45%) and 5.35 GHz (BW = 240 MHz, 4.46%), respectively, for IEEE 802.11a/b/g WLAN applications. The circular polarizations for dual‐band are demonstrated with AR spectrum and electric field intensities. Results included with frequency responses, radiation patterns, and electric field intensities are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 876–880, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24204