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.

Moreover, we would like to note that the folded antenna has much smaller size than the unfolded antenna, in addition to the bandwidth improvement in the DCS band.An absolute gain including the return loss and radiation efficiency was measured. The measured radiation patterns for the proposed antenna at 1 and 2 GHz are presented in Figure 6. The radiation patterns of H, E1, and E2 planes were measured in the x-y, z-x, and y-z planes, respectively. In the x-y plane, the radiation pattern at 1 GHz had quite good omni-directional characteristics. The radiation pattern gets more directional in the high-order resonant 2 GHz band. For the GSM and DCS bands, maximum absolute antenna gains (G 0abs ) were Ϫ0.05 and Ϫ0.13 dBi, respectively. These radiation patterns show that the proposed antenna had a good radiation efficiency. CONCLUSIONA dual-band small chip antenna was designed to satisfy requirements for operation in the GSM and DCS bands. The impedance bandwidth and resonant frequency of each band was controlled by the intercoupling capacitance of the metallic structure. The intercoupling capacitance was created by folding a metallic structure. The resonant frequencies were nonuniformly shifted due to the intercoupling capacitance. This property was very useful in controlling the resonance frequencies and their corresponding bandwidths. The simulated and measured results show that the proposed antenna satisfies the requirements for both GSM and DCS bands simultaneously. This resonanceshift effect caused by the folding intercoupling capacitance can be usefully exploited in designing a multiband antenna with high-order resonance phenomena. printed monopole, Electron Lett 28 (1992), 1326 -1327. 4. M. Makimoto and S. Yanashita, Microwave resonator and filters for wireless communication, Springer Verlag, New York, 2000, pp. 84 -87. 5. C.A. Balanis, Antenna theory and analysis and design, Wiley, New York, 2005, pp. 177-217. ABSTRACT: Dielectric resonator-loaded circular microstrip patch antennas can be used as an alternative way to generate circular polarization. The dielectric resonator is placed on the edge of the circular microstrip patch antenna to result both strong coupling effect and two degenerated orthogonal modes. Then, we choose the feeding point, the placed position and size of DR, and the height of antenna as key tuning parameters; both wide circular polarization and impedance matching are achieved. Application is given for WLAN 2.4 GHz band. Both simulated and measured data are matched well. Measured results show that the center frequency is at 2.45 GHz. The impedance bandwidth is 19.2%. Besides, the axial ratio bandwidth is 3.7% (2.39 -2.48 GHz). The radiation patterns are broadside radiations and high antenna gain of 8.6 dBic is achieved.

In this letter, we propose a novel multiband antenna which can be integrated into a laptop computer for WLAN and WWAN applications. The antenna, evolved from a dual‐band inverted‐F antenna, is mounted on the top‐edge of a vertical ground plane of LCD panel. By adding four parasitic resonators which are short‐circuited quarter‐wavelength elements, the antenna can achieve wideband performance to cover GSM850/GSM900/DCS/PCS/UMTS and 802.11a/b/g. A simulation was performed by HFSS to optimally design the antenna, and then a practical structure was also fabricated to verify the simulation results. The measured antenna parameters as well as the radiation efficiency are presented to validate the proposed antenna. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1803–1807, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24501

A compact shorted rectangular‐ring slot antenna fed by a coplanar waveguide is presented for circular polarization operations. This proposed antenna has only 40 mm square size in the applications of WLAN 2.4 GHz band. It seems the most compact size while referenced to other shorted ring slot antennas in recent articles. The reduced size is over 30% will save much cost and antenna can apply to portable devices. Simulated and measured data are matched in the reflection coefficient, axial ratio (AR), radiation patterns, and gain. Its measured center frequency and impedance bandwidth are 2.38 GHz and 15.1%, respectively. Also, the frequency of minimum axial‐ratio and axial‐ratio bandwidth are 2.43 GHz and 4.1%, respectively. From the bandwidths of view, both impedance and AR bandwidths can cover the 2.4 GHz band's applications. The radiation patterns are broadside radiations. Forward radiation belongs to right hand circular polarization and backward one is left hand circular polarization, respectively. Also, antenna gain is about 3 dBic in the operating band of WLAN 2.4 GHz band. The antenna performances and compact size of the proposed antenna are easy to be applied in the consumer products. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2229–2232, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24524

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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

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CPW-fed dual rectangular ceramic dielectric resonator antennas through inductively coupled slots have been studied by experiment. A better bandwidth is achieved if these compare with only single dielectric resonator as antennas. Also, these antennas can be easily done the input impedance matching by several parameters like adjusting the length of inductive slots, the space between dielectric resonators. and the offset distance of DR center to the center of ended inductive slots. I. Introduction:The ceramic dielectric resonator antennas [l-21 become more and more popular in the microwave and millimeter wave applications for those advantages such as without conductor loss, frequency stability in the variation of temperature for its low temperature coefficient, and different radiation patterns depending on which mode is excited. Also DRA with high permittivity can reduce the size hugely. In the consumer applications for operating frequency less than 3GHz, DRA still has bandwidth problems for its high Q value. In this paper, DRA with relative permittivity of 36 and rectangular body of 18.66mm*18.66mm*6mm is adopted, and dual resonators are introduced to enhance the bandwidth by suitable arrangement of the mutual coupling.Recently, CPW has become a trend in the feeding line for the circuit and antenna design. There are some advantages in the CPW such as connecting the shunt andor 0-7803-8302-8