Influence of antenna configuration on achievable throughput in real indoor propagation environment for 2-by-2 single-user MIMO in LTE-advanced uplink

This paper clarifies the influence of the antenna configuration on the achievable throughput in a real indoor propagation environment for 2-by-2 single-user (SU) multiple-input multiple-output (MIMO) in the Long Term Evolution (LTE)-Advanced uplink using single carrier-based radio access. In indoor experiments conducted in an office at walking speed, we consider four antenna configurations: co-polarized antennas with a long or small separation, cross-polarized antenna, and a distributed antenna arrangement. The experimental results show that when rank-2 MIMO spatial multiplexing is applied, the cross-polarized antenna configuration achieves a higher user throughput than the other antenna configurations. Furthermore, we show that when closed-loop rank-1 precoding is applied, the cross-polarized antenna configuration is effective in stably achieving a relatively high throughput regardless of the tilt angle of the mobile station transmitter antenna, although the other antenna configurations indicate better throughput under ideal antenna-tilt angle conditions.     

机载MIMO-SAR线性阵列天线配置研究

等效相位中心原理的应用为多发多收合成孔径雷达(MIMO-SAR)的天线设计提供了更大的自由度。文中阐述了等效相位中心原理,分析了传统ARTINO天线配置,指出由于其发射阵元布设于机翼处而剧烈抖动造成图像模糊的问题。然后,对传统ARTINO天线结构进行了改进,并提出了发射居中紧凑和接收居中紧凑2种天线构形。最后,对4种天线构形的方向图进行了仿真。结果表明,MIMO-SAR采用等效相位中心原理进行天线结构配置,可以在保证天线方向图具有良好指向性的同时,提高天线配置的灵活性并降低成本。     

Analysis and optimization of an electrically small receivingantenna

A theoretical and experimental study of an optimum receiving antenna configuration that fits within certain allocated space requirements is presented. This optimum monopole antenna configuration is applicable for Loran-C reception. The antenna analysis is based on a quasi-static numerical study of a conducting body of revolution above a perfectly conducting ground plane. A general numerical algorithm is developed to determine the input impedance and the effective height of the antenna. In addition, the amplifier noise and its role in the choice of the optimum antenna are examined. Results are presented for cylindrical and truncated conical structures both with and without a top load     

Dual frequency wire antennas

A new type of dual frequency antenna is introduced by combining a helical and a monopole antenna. The antenna configuration is shown to operate at two discrete frequencies. i.e. ~900 and 1800 MHz. The size of the antenna configuration can be decreased at the cost of the bandwidth. The bandwidth is shown to increase by adding a reactive matching network to the antenna     

用于星载SAR的双频双极化天线

该文设计了共用一个物理孔径的双频双极化的微带天线。天线采用了可折叠的充气式聚酯薄膜介质结构，有较小的介电常数，较大的相对带宽。天线采用孔径耦合馈电方式，对L波段和S波段的馈电线路可各自优化。讨论了此天线的交叉极化特性和阻抗区配，计算了天线的各个参数和天线用于星载SAR时的系统性能指标。     

双弯曲赋形反射面天线的外形选择

对双弯曲赋形反射面外形特征进行了理论分析，研究了不同外形反射面对天线电性能的影响，给出了选择反射面外形的方法，对双弯曲赋形反射面天线的设计有一定的帮助。     

Development of a Cavity-Backed Broadband Circularly Polarized Slot/Strip Loop Antenna With a Simple Feeding Structure

A cavity-backed loop antenna is developed for producing broadband circularly polarized (CP) radiation. The antenna configuration consists of a slot loop and a strip loop. The slot loop radiates a CP wave at a lower frequency while the strip loop produces CP radiation at a higher frequency. A combination of the two frequencies leads to a bandwidth enhancement. The slot/strip loop antenna is fed by a single straight microstrip line. It is demonstrated that the cavity-backed slot/strip loop antenna can achieve an axial ratio (les 3 dB) bandwidth of 19% with good impedance matching. The antenna configuration is described and the operating principles for broadband circular polarization and impedance matching are analyzed. The antenna performance is confirmed by experimental results.     

A new log-periodic dipole antenna

A log-periodic antenna having triangular dipoles as its constituent elements is presented. The design criterion and its electrical properties are discussed. The proposed configuration is compared with the conventional log-periodic dipole antenna. It is shown that this configuration offers a better frequency transition, bettor gain and a reduction in the axial length over the conventional log-periodic dipole array.     

Adaptive Counting Rule for Cooperative Spectrum Sensing Under Correlated Environments

We propose in this paper a dual-antenna-array (with transmitter antenna array and receiver antenna array) architecture, where the antenna elements are divided into several antenna element sets and each traffic channel is transmitted over an antenna element set, to realize the multiple traffic channels set up by a user. A SINR feedback based algorithm, which can regulate the transmission rate by iteratively adjusting the power on each traffic channel, is proposed to execute the rate control for the proposed dual-antenna-array architecture under cochannel interference. It is shown that the proposed algorithm can make the throughput meet the throughput requirement or achieve the weighted bandwidth sharing for certain fairness. In addition, we further propose a traffic channel configuration algorithm to help the SINR feedback based algorithm find the optimal traffic channel configuration that can meet the throughput requirement for each traffic channel or results in the maximal total throughput for each user.     

一种新型的介质反射面天线

提出了一种新型的多层介质结构的反射面天线，反射平面上所需要的相位补偿通过选择合适的介质厚度来实现，使用几个多层圆形介质即可满足条件。与传统的高增益天线相比，该结构设计简单，加工方便。验证了几种不同层数的结构和一个等口径的抛物面反射面天线。加工并测试了一个采用Vivaldi做馈源的4层结构的反射面天线。仿真和测试结果均表明该天线具有良好性能。     

Circular-polarised dielectric resonator antenna excited by dualconformal strips

A circular-polarised cylindrical dielectric resonator antenna excited by dual conformal strips is investigated experimentally. The configuration offers a wide axial-ratio bandwidth of 20%. We measured axial ratio, radiation patterns and antenna gain of the configuration are presented and discussed     

Optimizing antenna configuration for MIMO systems with imperfect channel estimation

We study the optimal antenna configuration (i.e. number of transmit and receive antennas) for multiple-input multiple-output systems in pilot-symbol-assisted modulation schemes with imperfect channel estimation. We assume block flat-fading channels and focus on a practical range of high signal-to-noise ratio. An ergodic capacity lower bound is used as the objective function to be maximized. We analytically study the capacity gain from adding extra antennas to the transmitter or to the receiver in two different scenarios. Our numerical results show that the optimal antenna configuration under imperfect channel estimation can be significantly different from that under perfect channel estimation assumption. In addition, we investigate the capacity gain from optimizing antenna configuration and find that the gain can be larger than that achieved by optimizing transmit power over pilot and data symbols, particularly for large block lengths.     

Shorted fractal Sierpinski monopole antenna

A novel configuration of a shorted fractal Sierpinski gasket antenna is proposed. Using only half the structure of a conventional Sierpinski gasket, the antenna is folded over to be parallel to the ground plane, to form an element that is, in some ways, similar to the inverted L antenna. A shorting pin is then placed at the far end of the antenna. A quasi log periodic resonance behaviour is observed     

一种新型的层叠式介质埋藏贴片八木天线

为了解决平面式微带贴片八木天线的主波束不能与微带天线基片平面垂直的问题,运用微带天线耦合理论、八木天线原理和微带天线理论,借鉴八木天线设计经验和微带天线制作技术,研制出了一种新型的层叠式介质埋藏贴片八木天线,并提出在八木天线振子两旁增加“栅栏”的改进结构形式。经仿真计算和实物天线测试证明：这种天线性能优于平面式的微带贴片八木天线。     

Resonant Meta-Surface Superstrate for Single and Multifrequency Dipole Antenna Arrays

The design of a multifrequency dipole antenna array based on a resonant meta-surface superstrate is proposed. The behavior of a single element that is closely placed to a meta-surface is experimentally investigated. The proposed meta-surface is based on resonating unit cells formed by capacitively loaded strips and split ring resonators. By tuning a dipole antenna to the pass band of the meta-surface, the physical area is effectively illuminated enhancing the radiation performance. The gain, radiation efficiency and effective area values of the whole configuration are compared to the ones obtained with a single dipole without superstrate. Radiation efficiency values for the proposed configuration of more than 80% and gain values of more than 4.5 plusmn 1 dB are obtained. Based on this configuration, simulated results of a multifrequency antenna array are presented. Distinctive features of this configuration are high isolation between elements (20 dB for a distance of lambda₀/4), and low back radiation.     

Dual frequency multilayered circular patch antenna withself-diplexing function

A novel type of dual frequency and double-layered patch antenna with self-diplexing function is presented. Experimental results of the proposed antenna which consists of a circular patch antenna and a ring patch antenna with partially shorting planes are shown to verify the practicality of the new antenna configuration     

Annular slot-coupled dielectric resonator antenna

An annular slot-coupled dielectric resonator antenna is investigated experimentally. As compared with the previous rectangular-slot version, the new configuration offers a much wider bandwidth of 18%. The return loss, radiation patterns, and antenna gain of the configuration have been measured and are discussed     

Compact stripline-fed meander slot antenna

A meander-type slot antenna fed by a stripline is proposed for use in miniaturised personal communication systems. By varying the slot configuration of the antenna, a 56% smaller antenna to substitute the conventional slot antenna is achieved. Simulated and measured results are presented     

一种新型的超宽带树形天线

提出了一种新型的双分枝树形超宽带天线,该天线是在矩形树形天线基础上由阶梯形缺口构成,采用了部分接地面技术和分形概念,测量结果表明天线的输入阻抗带宽达71.4%(2.7～5.7 GHz),同时数值仿真表明阶梯形缺口有利于天线阻抗匹配的改善,该天线为全向辐射,方向图与偶极子天线类似,天线增益为2.16～4.49 dB(3～5 GHz),与矩形树形天线相比,双分枝树形辐射单元面积减少28.5%。     

Study of electrically small printed chakra (wheel) antenna

A novel printed antenna configuration in the form of a chakra (wheel) is presented. The antenna has many design parameters, such as axle radius, rim radius, and shaft location, and exhibits a very low design frequency which is five times smaller than that of a regular circular microstrip patch antenna of the same size