A novel differential quasi-Yagi antenna is first presented and compared with a normal single-ended counterpart.The simulated and measured results show that the differential quasi-Yagi antenna outperforms the conventio...A novel differential quasi-Yagi antenna is first presented and compared with a normal single-ended counterpart.The simulated and measured results show that the differential quasi-Yagi antenna outperforms the conventional single-ended one.The differential quasi-Yagi antenna is then used as an element for linear arrays.A study of the coupling mechanism between the two differential and the two singleended quasi-Yagi antennas is conducted,which reveals that the TE0 mode is the dominant mode,and the driver is the decisive part to account for the mutual coupling.Next,the effects of four decoupling structures are respectively evaluated between the two differential quasi-Yagi antennas.Finally,the arrays with simple but effective decoupling structures are fabricated and measured.The measured results demonstrate that the simple slit or air-hole decoupling structure can reduce the coupling level from−18 dB to−25 dB and meanwhile maintain the impedance matching and radiation patterns of the array over the broad bandwidth.The differential quasi-Yagi antenna should be a promising antenna candidate for many applications.展开更多
A directional ultra-wideband(UWB)antenna with improved radiation patterns is presented.The proposed sheme comprises a differential-fed microstrip antenna and a rectangular cavity.The hexagon-shaped slot and four trian...A directional ultra-wideband(UWB)antenna with improved radiation patterns is presented.The proposed sheme comprises a differential-fed microstrip antenna and a rectangular cavity.The hexagon-shaped slot and four triangle-cut corners on the ground plane of the planar antenna are used to improve the impedance matching within the UWB frequency range.A rectangular cavity is used as the reflector for the planar microstrip antenna,so as to achieve directed radiation.The measured results indicate that the designed antenna exhibits a stable broadside directional radiation patterns within the entire operating frequency band.Furthermore,thanks to the differentially driven technique,the cross-polarization is greatly decreased and the polarization purity is maintained in a high level.展开更多
Based on the Complex Orthogonal Linear Dispersion (COLD) code,a novel linear Differ- ential Space-Time Modulation (DSTM) design is proposed in this paper.Compared with the existing nonlinear DSTM schemes based on grou...Based on the Complex Orthogonal Linear Dispersion (COLD) code,a novel linear Differ- ential Space-Time Modulation (DSTM) design is proposed in this paper.Compared with the existing nonlinear DSTM schemes based on group codes,the proposed linear DSTM scheme is easier to design, enjoys full diversity and allows for a simplified differential receiver,which can detect the transmitted symbols separately.Furthermore,compared with the existing linear DSTM based on orthogonal design, our new construction can be applied to any number of transmit antennas.Similar to other algorithms, the proposed scheme also can be demodulated with or without channel estimates at the receiver,but the performance degrades approximately by 3dB when estimates are not available.展开更多
This paper presents a novel method for polarized antenna transmission utilizing a differential technique. The method uses a linear cross-polarized antenna, for example, a vertical and horizontal polarized antenna, imp...This paper presents a novel method for polarized antenna transmission utilizing a differential technique. The method uses a linear cross-polarized antenna, for example, a vertical and horizontal polarized antenna, improving performance and power efficiency of wireless communications. Hence a linear relationship between the capacity of the systems and the number of cross-polarized antennas exists. The result shows the fact that this method enhances the SNR comparing to other systems. This solution is simple, compact and does not require any bandwidth expansion.展开更多
Driven by the great demand for highly integrated wireless system-on-chip and system-in-package devices,there has recently been increas-ing interest in the research and development of differential antennas.Many studies...Driven by the great demand for highly integrated wireless system-on-chip and system-in-package devices,there has recently been increas-ing interest in the research and development of differential antennas.Many studies on the design,analysis,and measurement of differential antennas have been published.This paper presents an overview of the fundamentals and applications of differential antennas.First,it compares differential to bal-anced and single-ended to unbalanced antennas and explains why the new terms(differential and single-ended antennas)should be adopted instead of the old terms(balanced and unbalanced antennas).Second,it addresses the quantitative relationship between a differential antenna and its single-ended counterpart,which is important and useful because the properties of either the differential or single-ended antenna can be determined from the other with a known solution.Third,it describes how differential antennas can be measured,with a special emphasis on the balun method.Fourth,it classifies dif-ferential antennas into wire,slot,microstrip,printed,and dielectric resonator antennas to better present their suitability and functionality.Fifth,it pro-vides application examples of differential antennas from simple discrete wire to sophisticated microstrip designs.Finally,it is argued that the old paradigms of lower gains and bulkier sizes of differential antennas as compared to single-ended antennas do not always hold true;for instance,differen-tial microstrip patch antennas can possess comparable or even smaller sizes and higher gain values than single-ended microstrip patch antennas.展开更多
文摘A novel differential quasi-Yagi antenna is first presented and compared with a normal single-ended counterpart.The simulated and measured results show that the differential quasi-Yagi antenna outperforms the conventional single-ended one.The differential quasi-Yagi antenna is then used as an element for linear arrays.A study of the coupling mechanism between the two differential and the two singleended quasi-Yagi antennas is conducted,which reveals that the TE0 mode is the dominant mode,and the driver is the decisive part to account for the mutual coupling.Next,the effects of four decoupling structures are respectively evaluated between the two differential quasi-Yagi antennas.Finally,the arrays with simple but effective decoupling structures are fabricated and measured.The measured results demonstrate that the simple slit or air-hole decoupling structure can reduce the coupling level from−18 dB to−25 dB and meanwhile maintain the impedance matching and radiation patterns of the array over the broad bandwidth.The differential quasi-Yagi antenna should be a promising antenna candidate for many applications.
基金supported in part by the National Natural Science Foundation of China(Nos.61472324,61073106,61540028)
文摘A directional ultra-wideband(UWB)antenna with improved radiation patterns is presented.The proposed sheme comprises a differential-fed microstrip antenna and a rectangular cavity.The hexagon-shaped slot and four triangle-cut corners on the ground plane of the planar antenna are used to improve the impedance matching within the UWB frequency range.A rectangular cavity is used as the reflector for the planar microstrip antenna,so as to achieve directed radiation.The measured results indicate that the designed antenna exhibits a stable broadside directional radiation patterns within the entire operating frequency band.Furthermore,thanks to the differentially driven technique,the cross-polarization is greatly decreased and the polarization purity is maintained in a high level.
基金Supported by the National Natural Science Foundation of China (No.60372055)National High Technology Research and Development Project of China (No.2003AA123320)the National Doctoral Foundation of China (No.20020698024,No.20030698027).
文摘Based on the Complex Orthogonal Linear Dispersion (COLD) code,a novel linear Differ- ential Space-Time Modulation (DSTM) design is proposed in this paper.Compared with the existing nonlinear DSTM schemes based on group codes,the proposed linear DSTM scheme is easier to design, enjoys full diversity and allows for a simplified differential receiver,which can detect the transmitted symbols separately.Furthermore,compared with the existing linear DSTM based on orthogonal design, our new construction can be applied to any number of transmit antennas.Similar to other algorithms, the proposed scheme also can be demodulated with or without channel estimates at the receiver,but the performance degrades approximately by 3dB when estimates are not available.
文摘This paper presents a novel method for polarized antenna transmission utilizing a differential technique. The method uses a linear cross-polarized antenna, for example, a vertical and horizontal polarized antenna, improving performance and power efficiency of wireless communications. Hence a linear relationship between the capacity of the systems and the number of cross-polarized antennas exists. The result shows the fact that this method enhances the SNR comparing to other systems. This solution is simple, compact and does not require any bandwidth expansion.
文摘Driven by the great demand for highly integrated wireless system-on-chip and system-in-package devices,there has recently been increas-ing interest in the research and development of differential antennas.Many studies on the design,analysis,and measurement of differential antennas have been published.This paper presents an overview of the fundamentals and applications of differential antennas.First,it compares differential to bal-anced and single-ended to unbalanced antennas and explains why the new terms(differential and single-ended antennas)should be adopted instead of the old terms(balanced and unbalanced antennas).Second,it addresses the quantitative relationship between a differential antenna and its single-ended counterpart,which is important and useful because the properties of either the differential or single-ended antenna can be determined from the other with a known solution.Third,it describes how differential antennas can be measured,with a special emphasis on the balun method.Fourth,it classifies dif-ferential antennas into wire,slot,microstrip,printed,and dielectric resonator antennas to better present their suitability and functionality.Fifth,it pro-vides application examples of differential antennas from simple discrete wire to sophisticated microstrip designs.Finally,it is argued that the old paradigms of lower gains and bulkier sizes of differential antennas as compared to single-ended antennas do not always hold true;for instance,differen-tial microstrip patch antennas can possess comparable or even smaller sizes and higher gain values than single-ended microstrip patch antennas.
