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ABSTRACT: This letter proposes a reconfigurable microstrip patch antenna with polarization states being switched among linear po-larization (LP), left-hand (LH) and right-hand (RH) circular po-larizations (CP). The CP waves are excited by two perturbation elements of loop slots in the ground plane. A p-i-n diode is placed on every slot to alter the current direction, which determines the polarization state. The influences of the slots and p-i-n diodes on antenna performance are minimized because the slots and diodes are not on the patch. The simulated and measured results verified the effectiveness of the proposed antenna configuration. The exper-imental bandwidths of the 10-dB reflection coefficient for LHCP and RHCP are about 60 MHz, while for LP is about 30 MHz. The bandwidths of the 3-dB axial ratio for both CP states are 20 MHz with best value of 0.5 dB at the center frequency on the broadside direction. Gains for two CP operations are 6.4 dB, and that for the LP one is 5.83 dB. This reconfigurable patch antenna with agile po-larization has good performance and concise structure, which can be used for 2.4-GHz wireless communication systems.
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ABSTRACT: The micro-genetic algorithm (MGA) optimization combined with the finite-difference time-domain (FDTD) method is applied to
design a band-notched ultra wide-band (UWB) antenna. A U-type slot on a stepped U-type UWB monopole is used to obtain the
band-notched characteristic for 5 GHz wireless local area network (WLAN) band. The measured results show that voltage standing
wave ration (VSWR) less than 2 covers 3.1–10.6 GHz operating band and VSWR more than 2 is within 5.150–5.825 GHz notched one
with the highest value of 5.6. Agreement among the calculated, HFSS simulated and measured results validates the effectiveness
of this MGA-FDTD method, which is efficient for UWB antennas design.
Journal of Shanghai University (English Edition) 04/2012; 13(5):375-378.
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ABSTRACT: The micro-genetic algorithm (MGA) optimization combined with the finite-difference time-domain (FDTD) method is applied to design a band-notched ultra wide-band (UWB) antenna in this article. A U-type slot on a stepped U-type UWB monopole is used to obtain the band-notched characteristic for 5 GHz WLAN band. The measured VSWR less than 2 covers the operating band of 3.1-10.6 GHz and VSWR more than 2 is within the notched band of 5.15-5.825 GHz with the highest value of 5.6. The measured patterns and the simulated gain show that the antenna can be applied in various UWB communication systems.
Millimeter Waves, 2008. GSMM 2008. Global Symposium on; 05/2008
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ABSTRACT: A compact semi-elliptical patch antenna fed by a tapered coplanar waveguide (CPW) is presented. The simulated and experimental results demonstrate that the antenna possesses the desirable super-wideband (SWB) characteristics, achieving a ratio bandwidth of 19.7:1 for VSWRles2, and exhibits a nearly omni-directional radiation pattern, while its area is only about 0.15 lambda<sub>1</sub> times 0.2 1 lambda<sub>1</sub>, where lambda<sub>1</sub> is the wavelength of the lowest operating frequency.
Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2007 International Symposium on; 09/2007
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ABSTRACT: The circularly polarized antennas fed by aperture coupling, which are applied in rectennas, have been researched. The double-layer structures, which put the feed networks and the radiating patches in the different sides, provide several good performances. First, it minimizes the influence of feedlines on the patches. Then, the gain and bandwidth can be improved in some degrees and it is easy to be integrated with other passive or active devices to construct rectennas of the RF front-ends. It also reduces the bulk of the rectennas. The influences of the array distance d on the XPD, return loss, gain and axial ratio have been analyzed in detail. A 4-element array has been designed with measured 800 MHz bandwidth of S<sub>11</sub> less than -15 dB and optimized 450 MHz bandwidth of AR less than 3 dB being obtained
Antennas and Propagation Society International Symposium 2006, IEEE; 08/2006
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ABSTRACT: A rigorous finite-difference time-domain (FDTD) modeling method has been presented to analyze the Gunn diodes covering three grid cells in the axial direction. The numerical results of an active antenna are near to the measured results and better than the computed ones in previous studies. This approach is convenient to study millimeter and sub-millimeter wave circuits with nonlinear lumped elements. According to the practical grid structures, the iterated field equations group of the diodes occupying two, four or more grid cells can be achieved easily
Antennas and Propagation Society International Symposium 2006, IEEE; 08/2006
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ABSTRACT: A study of the numerical stability of the higher-order finite-difference time-domain (i.e., FDTD (2, 4)) technique is proposed for calculating the uniform regions and the lumped inductors loaded regions. In the lumped inductors loaded region, six different discrete instances including explicit, implicit, and semi-implicit schemes are analyzed in detail, and the stable conditions of these schemes are obtained by using Routh-Hurwitz criterion. The calculated results validate these stable conditions.
Microwave Conference Proceedings, 2005. APMC 2005. Asia-Pacific Conference Proceedings; 01/2006
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ABSTRACT: A novel polarization-agile microstrip antenna array is proposed, in which the polarization agility from linear to circular polarization for the whole array is realized easily by controlling a single phase-shift circuit. Using the corner-fed square patch element, a new 16 element dual-polarized array with high isolation and low cross-polarization is designed and analyzed by the extended multiport network method. A special FET phase shifter circuit is created, where 0° or 90° phase shift between dual ports is electrically switched. Experimental results are presented to verify the theory, and measured circularly-polarized radiation patterns show a boresight axial ratio of 0.5 dB. Another experiment that connects a low noise amplifier together with the phase-shift circuit is also introduced, realizing both polarization agility and power amplification with one active circuit.
IEEE Transactions on Antennas and Propagation 02/2004; · 2.15 Impact Factor
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ABSTRACT: A systematic study on the dual-polarized corner-fed microstrip antenna element and arrays with thin single-layer structure is presented. The impedance matrices and S-parameters of the element and arrays are investigated by the proposed extended multiport network method (EMNM). The co- and cross-polarization patterns are also analyzed. It is shown that this kind of antenna element has an isolation about 10 dB higher than that of a conventional edge-fed square patch. A series of new dual-polarized arrays of corner-fed patches have been designed and analyzed based on the EMNM. The experimental results of five arrays indicate that these arrays achieve an isolation of 27∼38 dB with a maximum of higher than 28∼58 dB and cross-polarization level of lower than -23∼ -30 at boresight, which are substantially better than those of similar dual-polarized arrays of edge-fed patches. All theoretical results are in good agreement with experimental ones.
IEEE Transactions on Antennas and Propagation 11/2002; · 2.15 Impact Factor
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ABSTRACT: A novel polarization-agile microstrip antenna array is proposed, in which the polarization agility from linear to circular polarization for the whole array is achieved by electrically controlling one phase-shift circuit only. Using the corner-fed square patch element, a new 16-element dual-polarized array with high isolation and low cross-polarization is designed. A special FET phase shifter circuit is created. The experimental results are presented to verify the theory while circular polarization radiation patterns are measured with a boresight axial ratio of 0.5 dB.
Antennas and Propagation Society International Symposium, 2002. IEEE; 02/2002
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ABSTRACT: New analytical expressions for the input and mutual impedance of two kinds of dual-polarization square-patch antenna double fed at the orthogonal edges or corners are obtained using the Green's function approach based on the planar circuit principle. The frequency characteristics of the input impedance, VSWR, and isolation are analyzed and verified by the published data and experiments. The calculating formulas are very efficient with little computation, and are suitable for engineering design. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 26: 153–156, 2000.
Microwave and Optical Technology Letters 06/2000; 26(3):153 - 156. · 0.62 Impact Factor
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ABSTRACT: A new design of dual-polarized single-layer array with 16
corner-fed square patch elements is presented and the co- and
cross-polarization radiation patterns are analyzed. The array is
interconnected with low-noise amplifiers and the experimental results
are compared with the passive ones. It is observed that an extra gain of
12 dB is obtained while the radiation patterns have nearly no changes.
The bandwidth and the isolation are also improved in comparison with
those of the passive array
Antennas and Propagation Society International Symposium, 2000. IEEE; 02/2000
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ABSTRACT: A novel amplifier-type polarization-agile active microstrip array is proposed, in which the polarization agility and amplification of the signal for the whole microstrip antenna array is achieved by electrically controlling only one active circuit. First, by using the corner-fed square patch element, a new 16-element dual-polarized array with high isolation and low cross-polarization is presented with the co- and cross-polarization radiation patterns. Then the design of the active circuits, composed of LNA (low noise amplifier) and the phase shifter, are introduced and the experimental and theoretical results are given.
Antennas, Propagation and EM Theory, 2000. Proceedings. ISAPE 2000. 5th International Symposium on; 02/2000
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ABSTRACT: A new low-cost dual-polarized microstrip antenna array with a single layer is proposed. Its element is the parallel corner-fed square patch with two ports. The design, analysis, and experimental results of a 12 GHz 16-element array on a 0.8 mm thick substrate are presented. Its measured isolation is 26.5 dB at 12 GHz and higher than 20 dB over 710 MHz. The 2:1 VSWR bandwidth is wider than 840 MHz (7%). The theoretical results agree well with the experimental results. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 176–179, 2000.
Microwave and Optical Technology Letters 01/2000; 24(3):176 - 179. · 0.62 Impact Factor
