In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectr...In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectral efficiency (SE) and received energy efficiency (EE) are investigated by considering four types of antenna arrays, including uniform linear array (ULA), uniform rectangular planar array (URPA), uniform hexagonal planar array (UHPA), and uniform circular planar array (UCPA), respectively. We focus on analysis at the antenna response vector and utilize the idea of orthogonal matching pursuit algorithm to seek the optimal hybrid precoder. Furthermore, the trade-off of precoding architectures is studied between SE and received EE. Simulation results show that if the uniform planar array antenna is more concentrated, the SE and receive EE will be higher. Considering SE and received EE, the performance of planar arrays outperform linear array. There exist different optimal radio-frequency chain numbers to maximize the SE for planar array and linear array. In addition, the PCA can achieve relatively higher received EE while the SE is close to the fully connected architecture and the full digital architecture.展开更多
The structure and the characteristic power spectrum of a new lower hybrid wave antenna on the HT-7 tokamak are briefly described in this paper. The main experimental properties with the new antenna have been demonstra...The structure and the characteristic power spectrum of a new lower hybrid wave antenna on the HT-7 tokamak are briefly described in this paper. The main experimental properties with the new antenna have been demonstrated by showing the dependence of current drive efficiency and particle confinement time on phase difference between adjacent waveguides of the antenna. A few preliminary analyses about the experimental results are also discussed in the paper.展开更多
The LHCD antenna that will be used in LH-2A is the original one used in LH-1M, which will be modified. We measured the feature of the antenna, including the reflection of main waveguide, VSWR, the phase shift between ...The LHCD antenna that will be used in LH-2A is the original one used in LH-1M, which will be modified. We measured the feature of the antenna, including the reflection of main waveguide, VSWR, the phase shift between the adjacent sub-waveguides and so on. The paper describes the measured results and spectrum calculation based on the measured parameters. From the works we can assess our antennas correctly, which will be useful in LHCD experiment on HL-2A in the years to come.展开更多
This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algo...This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algorithm is developed to analyze the coupled magnetic fields Which are very difficult to be calculated. The method and results obtained are helpful to study the eddy currents and electro-magnetic forces on metal plates which are placed in a rather complicated electro-magnetic environment.展开更多
This paper presents a modification of an existing cognitive antenna design which contains two antennas: one is a sensing that covers the band from 1 - 11 GHz and the other is a hybrid triangular reconfigurable antenna...This paper presents a modification of an existing cognitive antenna design which contains two antennas: one is a sensing that covers the band from 1 - 11 GHz and the other is a hybrid triangular reconfigurable antenna. Two antennas are combined together to create a new design which called Cognitive Antenna. The new shape of the reconfigurable antenna will affect the cognitive antenna so as to work at two different frequencies via rotation by 180°. At each rotation, the antenna takes single frequency from number of possible frequencies that sensing antenna would find.展开更多
Multipath signal processing is a promising technique for increasing the capacity of downlink frequency of satellite communication networks (S-PCN). The paper presents an approach to processing and reducing multipath s...Multipath signal processing is a promising technique for increasing the capacity of downlink frequency of satellite communication networks (S-PCN). The paper presents an approach to processing and reducing multipath signals received from S-PCN typified of mobile terminal users in clustered or mountainous environment. Use of hybrid linear adaptive antenna array technique and adaptive filtering technique provides improved performance by eliminating uncorrelated signal residing in antenna sidelobes.展开更多
It is well accepted that lower hybrid current drive （LHCD） is the most efficient method for non-inductive current drive in fusion devices and the effect of the current drive is dependent on not only microwave power ...It is well accepted that lower hybrid current drive （LHCD） is the most efficient method for non-inductive current drive in fusion devices and the effect of the current drive is dependent on not only microwave power but also its grill phase shift. This paper presents a new kind of feedback control system for antenna phase difference in LHCD experiments. In this highspeed control system, a lot of new technologies and methods are incorporated. The results of the experiments show a very good agreement with the system design.展开更多
毫米波大规模天线是目前5G研究中的热点技术之一,毫米波大规模天线可提供高增益波束和大带宽,能有效提升系统能量效率和容量。面向未来5G移动通信需求,提出一种基于数字-模拟混合波束形成架构的毫米波大规模天线设计方案。采取该方案,...毫米波大规模天线是目前5G研究中的热点技术之一,毫米波大规模天线可提供高增益波束和大带宽,能有效提升系统能量效率和容量。面向未来5G移动通信需求,提出一种基于数字-模拟混合波束形成架构的毫米波大规模天线设计方案。采取该方案,天线内部各单机功能界限清晰、接口明确,可极大提升天线系统的可测试性和可批量生产性。基于该设计方案研制了一款毫米波大规模天线样机,工作频率为28.6 GHz,带宽为1 GHz,天线共包括64个辐射单元,划分为4个子阵,每个子阵对应一个单独的数字收发通道。采取近场、OTA(Over The Air)的测试方法,完成了该样机的波瓣、等效辐射功率(EIRP)、矢量误差幅度(EVM)等指标的测试。该样机的研制及性能试验方法,均对未来毫米波大规模天线在5G移动通信系统中的广泛应用、大规模量产提供了很好的借鉴意义。展开更多
在对线天线的阻抗特性问题进行分析计算的过程中,采用伽列金矩量法(Galerkin moment method,Galerkin-MOM),综合分域基函数和全域基函数的优点,在幂级数函数的基础上,形成了一种简便有效的混合域基函数作为基函数和检验函数。并根据此...在对线天线的阻抗特性问题进行分析计算的过程中,采用伽列金矩量法(Galerkin moment method,Galerkin-MOM),综合分域基函数和全域基函数的优点,在幂级数函数的基础上,形成了一种简便有效的混合域基函数作为基函数和检验函数。并根据此混合域基函数,对同轴线激励的线天线的导纳特性进行了仿真计算。最终计算结果表明,该基函数简单有效,计算结果准确,有利于快速求解线状天线特性阻抗问题。展开更多
基金supported by the National Natural Science Foundation of China (No.61961018)the Jiangxi Province Foundation for Distinguished Young Scholar (No.20192BCB23013)+1 种基金the Jiangxi Province Natural Science Foundation of China (No.20171BAB202001, 20192ACB21003)the Science Program of Jiangxi Educational Committee (No.GJJ180307)
文摘In this paper, the performance of hybrid precoding is investigated for mmWave massive MIMO systems with different antenna arrays. The hybrid precoding with partially connected architecture (PCA) is adopted. The spectral efficiency (SE) and received energy efficiency (EE) are investigated by considering four types of antenna arrays, including uniform linear array (ULA), uniform rectangular planar array (URPA), uniform hexagonal planar array (UHPA), and uniform circular planar array (UCPA), respectively. We focus on analysis at the antenna response vector and utilize the idea of orthogonal matching pursuit algorithm to seek the optimal hybrid precoder. Furthermore, the trade-off of precoding architectures is studied between SE and received EE. Simulation results show that if the uniform planar array antenna is more concentrated, the SE and receive EE will be higher. Considering SE and received EE, the performance of planar arrays outperform linear array. There exist different optimal radio-frequency chain numbers to maximize the SE for planar array and linear array. In addition, the PCA can achieve relatively higher received EE while the SE is close to the fully connected architecture and the full digital architecture.
基金The project supported by the National Natural Science Foundation of China (No. 10205015)
文摘The structure and the characteristic power spectrum of a new lower hybrid wave antenna on the HT-7 tokamak are briefly described in this paper. The main experimental properties with the new antenna have been demonstrated by showing the dependence of current drive efficiency and particle confinement time on phase difference between adjacent waveguides of the antenna. A few preliminary analyses about the experimental results are also discussed in the paper.
文摘The LHCD antenna that will be used in LH-2A is the original one used in LH-1M, which will be modified. We measured the feature of the antenna, including the reflection of main waveguide, VSWR, the phase shift between the adjacent sub-waveguides and so on. The paper describes the measured results and spectrum calculation based on the measured parameters. From the works we can assess our antennas correctly, which will be useful in LHCD experiment on HL-2A in the years to come.
文摘This paper analyzes the eddy currents and the electro-magnetic forces on the lower hybrid wave (LHW) launching antenna on the superconducting Tohamak HT-7 by using a finite element circult method. A new iterative algorithm is developed to analyze the coupled magnetic fields Which are very difficult to be calculated. The method and results obtained are helpful to study the eddy currents and electro-magnetic forces on metal plates which are placed in a rather complicated electro-magnetic environment.
文摘This paper presents a modification of an existing cognitive antenna design which contains two antennas: one is a sensing that covers the band from 1 - 11 GHz and the other is a hybrid triangular reconfigurable antenna. Two antennas are combined together to create a new design which called Cognitive Antenna. The new shape of the reconfigurable antenna will affect the cognitive antenna so as to work at two different frequencies via rotation by 180°. At each rotation, the antenna takes single frequency from number of possible frequencies that sensing antenna would find.
文摘Multipath signal processing is a promising technique for increasing the capacity of downlink frequency of satellite communication networks (S-PCN). The paper presents an approach to processing and reducing multipath signals received from S-PCN typified of mobile terminal users in clustered or mountainous environment. Use of hybrid linear adaptive antenna array technique and adaptive filtering technique provides improved performance by eliminating uncorrelated signal residing in antenna sidelobes.
基金Meg-science Engineering Project of the Chinese Academy of Sciences
文摘It is well accepted that lower hybrid current drive （LHCD） is the most efficient method for non-inductive current drive in fusion devices and the effect of the current drive is dependent on not only microwave power but also its grill phase shift. This paper presents a new kind of feedback control system for antenna phase difference in LHCD experiments. In this highspeed control system, a lot of new technologies and methods are incorporated. The results of the experiments show a very good agreement with the system design.
文摘毫米波大规模天线是目前5G研究中的热点技术之一,毫米波大规模天线可提供高增益波束和大带宽,能有效提升系统能量效率和容量。面向未来5G移动通信需求,提出一种基于数字-模拟混合波束形成架构的毫米波大规模天线设计方案。采取该方案,天线内部各单机功能界限清晰、接口明确,可极大提升天线系统的可测试性和可批量生产性。基于该设计方案研制了一款毫米波大规模天线样机,工作频率为28.6 GHz,带宽为1 GHz,天线共包括64个辐射单元,划分为4个子阵,每个子阵对应一个单独的数字收发通道。采取近场、OTA(Over The Air)的测试方法,完成了该样机的波瓣、等效辐射功率(EIRP)、矢量误差幅度(EVM)等指标的测试。该样机的研制及性能试验方法,均对未来毫米波大规模天线在5G移动通信系统中的广泛应用、大规模量产提供了很好的借鉴意义。
文摘在对线天线的阻抗特性问题进行分析计算的过程中,采用伽列金矩量法(Galerkin moment method,Galerkin-MOM),综合分域基函数和全域基函数的优点,在幂级数函数的基础上,形成了一种简便有效的混合域基函数作为基函数和检验函数。并根据此混合域基函数,对同轴线激励的线天线的导纳特性进行了仿真计算。最终计算结果表明,该基函数简单有效,计算结果准确,有利于快速求解线状天线特性阻抗问题。
