The Experts below are selected from a list of 330 Experts worldwide ranked by ideXlab platform
Xulin Quan - One of the best experts on this subject based on the ideXlab platform.
-
Analysis and Design of a 45 $^{\circ}$ Slant-Polarized Omnidirectional Antenna
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Xulin Quan, Ronglin Li, Dimitris E. AnagnostouAbstract:A 45° slant-polarized Omnidirectional Antenna is proposed for mobile communication base stations. The proposed Antenna consists of four printed crossed-dipole elements which are rolled up into a cylinder for Omnidirectional radiation. Each crossed-dipole element is composed of a horizontal dipole and a vertical dipole. The 45° slant polarization is achieved by adjusting the lengths of the horizontal and vertical dipoles. A broadband feeding network consisting of four broadband baluns and an impedance matching circuit is introduced to feed the four crossed-dipole elements. Experimental results show that the Omnidirectionality or gain variation in the horizontal plane is less than 1 dB while the cross-polarization level is below -15 dB over a bandwidth of 15% (1.9-2.2 GHz). The 45° slant-polarized Omnidirectional Antenna has a bandwidth of 22% (1.75-2.18 GHz) for 15-dB return loss. Theoretical analysis and design procedure are presented.
-
A Broadband Dual-Polarized Omnidirectional Antenna for Base Stations
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Xulin QuanAbstract:A broadband vertically/horizontally dual-polarized Omnidirectional Antenna is proposed for mobile communications. The dual-polarized Antenna is a combination of a modified low-profile monopole for vertical polarization (VP) and a circular planar loop for horizontal polarization (HP). The modified low-profile monopole is a circular folded patch shorted by four tubes while the circular loop consists of four half-wavelength arc dipoles. The dual-polarized Omnidirectional Antenna achieves a bandwidth of ~ 25% (1.7-2.2 GHz) with an isolation of around 40 dB. The gain variations in the horizontal plane are less than 2.5 dB for VP and 1.5 dB for HP. An eight-element dual-polarized Antenna array is developed for base station applications. The Antenna gains of the array for both VP and HP are ~ 8 dBi with a difference of less than 1 dB. The beamwidths in the vertical plane are 9±1° for VP and 9±1.5° for HP. The cross-polarization levels in the horizontal plane for both VP and HP are lower than -20 dB.
-
development of a broadband horizontally polarized Omnidirectional planar Antenna and its array for base stations
Progress in Electromagnetics Research-pier, 2012Co-Authors: Xulin Quan, Ronglin Li, Jian Ye WangAbstract:A novel broadband horizontally polarized (HP) omnidi- rectional planar Antenna is developed for mobile communications. The proposed Antenna consists of four printed arc dipoles that form a cir- cular loop for HP Omnidirectional radiation. A broadband feeding net- work which includes four broadband baluns and an impedance match- ing circuit is designed to excite the four arc dipoles. An eight-element linear Antenna array is developed for 2G/3G base stations. A broad- band power divider is used to feed the Antenna array. Experimental results show that the HP Omnidirectional Antenna element has a band- width of 31% (1.66{2.27GHz) while its array has a bandwidth of 34% (1.67{2.35GHz) and an Omnidirectional Antenna gain of » 8dBi. Both of the Antenna element and its array have good omnidirectivity over the 10-dB return loss bandwidth. Simulated and measured results for the Antenna element and its array are presented.
Magdy F Iskander - One of the best experts on this subject based on the ideXlab platform.
-
a mng tl loop Antenna array with horizontally polarized Omnidirectional patterns
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A horizontally polarized Omnidirectional planar loop Antenna that employs an artificial mu-negative transmission line (MNG-TL) is proposed. The MNG-TL is designed using periodically loaded parallel-plate lines. The reactive loading is inspired by the zeroth-order resonator (ZOR), which has a propagation constant of zero. Due to the unique property of an infinite wavelength, the MNG-TL loop Antenna presented in this paper allows current along the loop to remain in phase so that a horizontal polarized Omnidirectional pattern is generated. A series-fed array, which is composed of four MNG-TL loop Antennas and operates at 2.4 GHz band, is designed, fabrication, and measured. The MNG-TL loop Antenna array offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 6.5 ~ 7.9 dBi and measured radiation efficiency exceeding 85% for covering bands. The concept extends the degrees of design freedom for horizontally polarized Omnidirectional Antenna array.
-
periodic leaky wave Antenna array with horizontally polarized Omnidirectional pattern
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A novel periodic leaky-wave Antenna for broadside radiation with horizontally polarized Omnidirectional pattern is proposed, designed and demonstrated experimentally. The objective is to achieve a horizontally polarized Omnidirectional Antenna array with highly directive beam. The proposed structure is based on combining the rotating electric field method and a leaky-wave Antenna design. By properly designing a unit cell with a pair of crossed dipoles spaced at a distance approximately equal to λg/4 at the center frequency, not only Omnidirectional radiation pattern with horizontal polarization is obtained by crossed dipoles fed in phase quadrature, but also the open-stopband effect exhibited at broadside scan is significantly reduced. The analysis and design of this structure are performed on the basis of a simple equivalent network model. A finite structure formed by 16-unit cell (32-element) for broadside beam is developed at the 2.4 GHz band, which offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 9.9-10.6 dBi and measured radiation efficiency of 90% for the covering bands.
Zhenghe Feng - One of the best experts on this subject based on the ideXlab platform.
-
horizontally polarized Omnidirectional Antenna array using cascaded cavities
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Le Chang, Zhijun Zhang, Zhenghe FengAbstract:A new structure of horizontally polarized (HP) Antenna array is presented for azimuthal Omnidirectional coverage. The proposed Antenna array is engineered by breaking the fringing field symmetry along the typical parallel strip-lines, which is implemented by loading field-block structures alternatively and periodically. In physics, the blocking structures constrain the fringing fields inside, producing a series of rectangular open cavities operating at the ${\rm{TM}}_{1n0}$ ( $n = 0.5$ ) mode. Counterintuitively, these asymmetric open cavities are able to generate an Omnidirectional radiation pattern in the $E$ plane with horizontal polarization, similar to the linear magnetic current array. In order to verify the design strategy, a five-unit center-fed cascaded cavity array is fabricated and tested. The measured bandwidth is 120 MHz (5.83–5.95 GHz) with reflection coefficient lower than −10 dB. The HP Omnidirectional pattern at 5.9 GHz provides a gain variation of 1.94 dB ranging from 6.7–8.64 dBi.
-
a mng tl loop Antenna array with horizontally polarized Omnidirectional patterns
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A horizontally polarized Omnidirectional planar loop Antenna that employs an artificial mu-negative transmission line (MNG-TL) is proposed. The MNG-TL is designed using periodically loaded parallel-plate lines. The reactive loading is inspired by the zeroth-order resonator (ZOR), which has a propagation constant of zero. Due to the unique property of an infinite wavelength, the MNG-TL loop Antenna presented in this paper allows current along the loop to remain in phase so that a horizontal polarized Omnidirectional pattern is generated. A series-fed array, which is composed of four MNG-TL loop Antennas and operates at 2.4 GHz band, is designed, fabrication, and measured. The MNG-TL loop Antenna array offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 6.5 ~ 7.9 dBi and measured radiation efficiency exceeding 85% for covering bands. The concept extends the degrees of design freedom for horizontally polarized Omnidirectional Antenna array.
-
periodic leaky wave Antenna array with horizontally polarized Omnidirectional pattern
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A novel periodic leaky-wave Antenna for broadside radiation with horizontally polarized Omnidirectional pattern is proposed, designed and demonstrated experimentally. The objective is to achieve a horizontally polarized Omnidirectional Antenna array with highly directive beam. The proposed structure is based on combining the rotating electric field method and a leaky-wave Antenna design. By properly designing a unit cell with a pair of crossed dipoles spaced at a distance approximately equal to λg/4 at the center frequency, not only Omnidirectional radiation pattern with horizontal polarization is obtained by crossed dipoles fed in phase quadrature, but also the open-stopband effect exhibited at broadside scan is significantly reduced. The analysis and design of this structure are performed on the basis of a simple equivalent network model. A finite structure formed by 16-unit cell (32-element) for broadside beam is developed at the 2.4 GHz band, which offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 9.9-10.6 dBi and measured radiation efficiency of 90% for the covering bands.
-
design of a dualband Omnidirectional planar microstrip Antenna array
Progress in Electromagnetics Research-pier, 2012Co-Authors: Kunpeng Wei, Zhijun Zhang, Zhenghe FengAbstract:This paper proposes and designs a new method of dualband Omnidirectional planar microstrip Antenna array. A cascade of transposed microstrip lines have been adapted to produce efiective Antenna structures that radiate Omnidirectionally, with high e-ciency, low re∞ection, and useful radiation patterns. In this paper, the Antenna structure has been found to have low-pass characteristics due to the periodic discontinuities at the transposed junctions. The analysis and design of the low-pass characteristic are performed according to the fllter theory of periodic structures and full-wave simulation. Therefore, a relatively higher frequency radiating array is appropriately designed with a low-pass flltering attribute, which prevents the lower frequency radiators from resonating at the relatively higher frequency. An air gap between adjacent transposed sections is proposed in order to enhance impedance matching, and a fork shape stub at the end is used as a virtual short point to enhance radiation at the higher frequency. Finally a single port dualband Omnidirectional Antenna array is obtained by locating the higher frequency radiating array with low-pass flltering attribute near the Antenna feed and a relatively lower frequency radiating array at the end. An example of a dualband Omnidirectional planar array is demonstrated experimentally, which operates at 2:32 » 2:56GHz and 5:65 » 6:10GHz with S11 < i10dB and a stable radiation pattern, and corresponding gains of 7:0 » 7:6dBi and 6:9 » 7:9dBi respectively.
K Sarabandi - One of the best experts on this subject based on the ideXlab platform.
-
a wideband circularly polarized Omnidirectional Antenna based on excitation of two orthogonal circular te 21 modes
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Behzad Yektakhah, K SarabandiAbstract:A novel wideband circularly polarized (CP) Omnidirectional Antenna operating at L-band is presented. The Antenna operates based on excitation of a field distribution similar to circular waveguide TE21 mode over a wide bandwidth. It is shown that the circular TE21 mode generates a linearly polarized far-field electric field over the horizontal plane with its polarization tilt angle varying as a function of azimuth angle. It is also shown that the tilt angle varies by 90° for an azimuthal angle increase of 45°. To obtain circular polarization, two circular TE21 modes are excited such that one mode is spatially rotated by 45° with respect to the other mode. The phase difference between two modes is 90°. The modes are excited by an array of 16 monopole sectorial loop Antennas to achieve a wide axial-ratio (AR) bandwidth. A right-handed CP Antenna based on the proposed structure is fabricated and tested against simulation results. A feed network including Wilkinson power dividers and low-pass/high-pass phase shifters is also designed and fabricated to feed the Antenna elements. The measurement results show 58% of 3-dB AR and 10-dB impedance bandwidth with the center frequency at 1.565 GHz. The total height of the Antenna is 47 mm.
-
a compact broadband horizontally polarized Omnidirectional Antenna using planar folded dipole elements
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Xiuzhang Cai, K SarabandiAbstract:A compact horizontally polarized (HP) Omnidirectional Antenna with broadband characteristic is presented. The Antenna is composed of four planar folded dipole Antennas (PFDAs) as radiation elements of a square array and a broadband microstrip feeding structure composed of baluns and matching networks. The folded dipole Antennas are chosen in order to achieve wide bandwidth operation within a compact size. The folded dipole elements are modified to compensate for the mutual coupling effects and also to improve the bandwidth and radiation performance of the Antenna. The Antenna is fabricated and its input impedance and radiation pattern are measured. The measured 10 dB return loss bandwidth is about 53.2% (1.19–2 GHz) and the gain variation in all directions of azimuth plane is less than 2 dB over the frequency band 1.2–1.9 GHz, and is increased to 2.8 dB at 2 GHz. The gain is almost constant over the entire band with a peak gain about 1.2 dB. The co-pol and cross-pol isolation is more than 20 dB for all azimuth directions and frequencies over the entire band.
Zhijun Zhang - One of the best experts on this subject based on the ideXlab platform.
-
horizontally polarized Omnidirectional Antenna array using cascaded cavities
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Le Chang, Zhijun Zhang, Zhenghe FengAbstract:A new structure of horizontally polarized (HP) Antenna array is presented for azimuthal Omnidirectional coverage. The proposed Antenna array is engineered by breaking the fringing field symmetry along the typical parallel strip-lines, which is implemented by loading field-block structures alternatively and periodically. In physics, the blocking structures constrain the fringing fields inside, producing a series of rectangular open cavities operating at the ${\rm{TM}}_{1n0}$ ( $n = 0.5$ ) mode. Counterintuitively, these asymmetric open cavities are able to generate an Omnidirectional radiation pattern in the $E$ plane with horizontal polarization, similar to the linear magnetic current array. In order to verify the design strategy, a five-unit center-fed cascaded cavity array is fabricated and tested. The measured bandwidth is 120 MHz (5.83–5.95 GHz) with reflection coefficient lower than −10 dB. The HP Omnidirectional pattern at 5.9 GHz provides a gain variation of 1.94 dB ranging from 6.7–8.64 dBi.
-
a mng tl loop Antenna array with horizontally polarized Omnidirectional patterns
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A horizontally polarized Omnidirectional planar loop Antenna that employs an artificial mu-negative transmission line (MNG-TL) is proposed. The MNG-TL is designed using periodically loaded parallel-plate lines. The reactive loading is inspired by the zeroth-order resonator (ZOR), which has a propagation constant of zero. Due to the unique property of an infinite wavelength, the MNG-TL loop Antenna presented in this paper allows current along the loop to remain in phase so that a horizontal polarized Omnidirectional pattern is generated. A series-fed array, which is composed of four MNG-TL loop Antennas and operates at 2.4 GHz band, is designed, fabrication, and measured. The MNG-TL loop Antenna array offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 6.5 ~ 7.9 dBi and measured radiation efficiency exceeding 85% for covering bands. The concept extends the degrees of design freedom for horizontally polarized Omnidirectional Antenna array.
-
periodic leaky wave Antenna array with horizontally polarized Omnidirectional pattern
IEEE Transactions on Antennas and Propagation, 2012Co-Authors: Kunpeng Wei, Zhenghe Feng, Zhijun Zhang, Magdy F IskanderAbstract:A novel periodic leaky-wave Antenna for broadside radiation with horizontally polarized Omnidirectional pattern is proposed, designed and demonstrated experimentally. The objective is to achieve a horizontally polarized Omnidirectional Antenna array with highly directive beam. The proposed structure is based on combining the rotating electric field method and a leaky-wave Antenna design. By properly designing a unit cell with a pair of crossed dipoles spaced at a distance approximately equal to λg/4 at the center frequency, not only Omnidirectional radiation pattern with horizontal polarization is obtained by crossed dipoles fed in phase quadrature, but also the open-stopband effect exhibited at broadside scan is significantly reduced. The analysis and design of this structure are performed on the basis of a simple equivalent network model. A finite structure formed by 16-unit cell (32-element) for broadside beam is developed at the 2.4 GHz band, which offers a horizontally polarized Omnidirectional radiation pattern with enhanced gain of 9.9-10.6 dBi and measured radiation efficiency of 90% for the covering bands.
-
design of a dualband Omnidirectional planar microstrip Antenna array
Progress in Electromagnetics Research-pier, 2012Co-Authors: Kunpeng Wei, Zhijun Zhang, Zhenghe FengAbstract:This paper proposes and designs a new method of dualband Omnidirectional planar microstrip Antenna array. A cascade of transposed microstrip lines have been adapted to produce efiective Antenna structures that radiate Omnidirectionally, with high e-ciency, low re∞ection, and useful radiation patterns. In this paper, the Antenna structure has been found to have low-pass characteristics due to the periodic discontinuities at the transposed junctions. The analysis and design of the low-pass characteristic are performed according to the fllter theory of periodic structures and full-wave simulation. Therefore, a relatively higher frequency radiating array is appropriately designed with a low-pass flltering attribute, which prevents the lower frequency radiators from resonating at the relatively higher frequency. An air gap between adjacent transposed sections is proposed in order to enhance impedance matching, and a fork shape stub at the end is used as a virtual short point to enhance radiation at the higher frequency. Finally a single port dualband Omnidirectional Antenna array is obtained by locating the higher frequency radiating array with low-pass flltering attribute near the Antenna feed and a relatively lower frequency radiating array at the end. An example of a dualband Omnidirectional planar array is demonstrated experimentally, which operates at 2:32 » 2:56GHz and 5:65 » 6:10GHz with S11 < i10dB and a stable radiation pattern, and corresponding gains of 7:0 » 7:6dBi and 6:9 » 7:9dBi respectively.
