A shorted square‐ring slot antenna with a branched slot is presented for the 1575 MHz and 2.4 GHz dual‐band operations. This proposed antenna can be designed by two steps. First, the shorted square‐ring slot antenna is designed for circular polarization in the GPS band. Then, a branched slot is added to the original structure to result linear polarization in the 2.4 GHz band. Because the added branched slot almost has no influence in the GPS band's characteristics, the design rule is very simple. The impedance and axial ratio bandwidths for the GPS band is 23.3% and 4.2%, respectively. Besides, the AR and antenna gain is 1.23 dB and 2.3 dBic at the frequency of 1575 MHz. The impedance bandwidth for the 2.4 GHz band is 4.5% and antenna gain at the center frequency of 2.445 GHz is 2.8 dBi. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 402–405, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24073

This article investigation develops and experimentally explores the dual-band design for a compact coplanar waveguide (CPW)-fed annular slot antenna loaded with conducting strips. In the proposed strip-loaded design, the arc-like metal strips excite the first resonant mode at the operating frequency, which is lower than that of the annular slot antenna, to achieve miniaturization. The prototype is implemented on a 0.8 mm FR-4 substrate with e r ¼ 4.4; the outer and inner radii of the compact annular slot are 9.0 mm and 6.5 mm, respectively. The return loss of the proposed design reveals two operating bands with a VSWR of 2.5: 1 over bandwidths of 3.5% and 9.8%, respectively. Two resonant bands exhibit the broadside radiation patterns with the peak antenna gains of 1.3 dBi and 4.9 dBi, respectively.

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trade-off between good wavelength-selective reflection and wide tuning. The fabricated ADRF exhibited the maximum reflectivity of 0.34 for TE mode. The tuning range of the ADRF is 42 nm, which can be obtained by injecting 30 mA to one of the electrodes on top of the ADRF rings. Therefore, it is believed that a widely tunable hybrid laser can be realized economically if the proposed polymer ring-based ADRF is hybrid-integrated with a broadband light source such as reflective semiconductor optical amplifiers or SLDs. External cavity lasers composed of higher order gratings and SLDs integrated on PLC platform, ETRI J 29 (2007), 452-455. 4. B.E. Little, S.T. Chu, H.A. Haus, J. Foresi, and J.P. Laine, Microring resonator channel dropping Filters, IEEE J Lightwave Technol 15 (1997), 998-1005.ABSTRACT: Shorted square-ring slot antennas with a rectangular slot are presented for the global positioning system (GPS) and thirdgeneration communication (3G) operations. The shorted square-ring slot antenna is used as the basic configuration for circular polarization in the GPS band. Then, an added rectangular slot inside the square-ring slot will radiate linearly polarized wave in the 3G band. Because the added slot has little influence in the GPS band's characteristics, the design rule is very simple. The experimental impedance and axial-ratio bandwidths for the GPS band are 19.8 and 4.5%, respectively. Also, the impedance bandwidth and the antenna gain for the 3G band are 14.9% and 2.5 dBi, respectively. The antenna characteristics such as bandwidths and gain satisfy the dual-band's antenna requirements. Especially, the antenna radiation patterns are very suitable to apply in the GPS and 3G systems. Figure 1 Geometrical configuration of a shorted square-ring slot antenna with a rectangular slot: (a) top view and (b) side view ABSTRACT: A compact printed monopole antenna for WLAN and WiMAX applications is proposed. By combining symmetrical G-shaped strips and a coupling-fed plate, fed by a 50 X microstrip transmission line, wide impedance bandwidths covering WLAN/2.4/5.2 and WiMAX/ Figure 6 Measured radiation patterns of the proposed antenna at 2.072 GHz in (a) x-z and (b) y-z planes, respectively

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