One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers

In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers.     

加载电磁带隙结构的低剖面等角螺旋天线

介绍了平面等角螺旋天线的原理和设计方法,运用以有限元法为原理的专业软件Ansoft HFSS对加平板式低剖面等角螺旋天线（EAS-PEC）进行了仿真;研究了一种加载电磁带隙结构的低剖面等角螺旋天线（EAS-EBG）,该天线是在保持低剖面和不扩大横切面积的情况下,将小型EBG结构插入加平板式低剖面等角螺旋天线中,以优化轴比。仿真结果表明,加载电磁带隙结构的模型在工作频带4～8GHz内降低了轴比（特别是在5～7GHz内降低了3dB的轴比）,且没降低增益。在不改变外形尺寸的情况下,为优化低剖面等角螺旋天线的性能提出了一种可行的技术途径。     

Comparison of the design of a contoured-beam and an elliptical-beamsatellite offset reflector antennas to cover the Taiwan island regionfor satellite communications

For the design of the satellite antenna for the future geostationary (GEO) satellite communication or DBS (direct broadcasting satellite) applications to serve the Taiwan Island region, it may be required to have a antenna beam which effectively covers the Taiwan region and reduces the antenna radiation level in the nearby area of mainland China. Two cases of the Ka-band (20 GHz) satellite antenna, a shaped offset reflector antenna to synthesize a contoured beam and an elliptical offset reflector antenna to generate an elliptical beam, have been studied. This paper presents the comparison and discussion of the antenna coverage performance of the two designs     

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.     

Internal Ultrawideband Monopole Antenna for Wireless USB Dongle Applications

A novel, ultrawideband (UWB) monopole antenna suitable to be mounted on the printed circuit board (PCB) of a wireless, universal, serial-bus (USB) dongle as an internal antenna is presented. The proposed antenna in the study is a U-shaped, metal-plate monopole antenna, easily fabricated from bending a simple metal plate onto a foam base of a compact size of 6times11times20 mm³. The antenna mainly comprises a pair of wide-ended radiating arms and a bevel-feed transition. When the antenna is mounted at the top portion of the PCB, one end of the radiating arm is also short-circuited to the system ground plane. With the proposed antenna structure, which can provide a very wide operating bandwidth of larger than 7.6 GHz, the antenna impedance bandwidth can easily cover the 3.1-10.6 GHz UWB band. Details of the antenna design are described, and experimental results of the constructed prototypes are presented and discussed     

基片集成波导双圆极化贴片天线的设计与实现

为了提高通信系统的通信容量,设计了一种基片集成波导(SIW)双圆极化贴片天线。该天线由耦合器、贴片天线构成。基于空腔模型研究,耦合器采用SIW结构,其输出端信号在较宽的带宽内具有良好的稳定性;在分析微带天线理论基础上,引入贴片天线作为辐射单元,结构简单,易于实现;在传输线模型理论中,天线输入端口采用共面波导(CPW)的转换结构是必不可少的,可以直接与SMA转接头相连,方便测试。该天线可以根据其应用需求调整工作极化方式,可以实现左旋圆极化(LHCP)和右旋圆极化(RHCP)。通过测试加工后的天线验证了仿真数据。结果表明,该天线相对带宽超过18%(19.5 GHz~23.5 GHz),在工作频率范围内,轴比参数小于2,可实现增益7.4 dB。     

Hybrid diversity combining techniques for DS‐CDMA over a multipath fading channel

The combined effect of antenna diversity and spread spectrum (SS) diversity for a direct sequence code division multiple access (DS‐CDMA) system using differential binary phase‐shift keying (DBPSK) modulation is evaluated. Both maximal ratio combining (MRC) and selection diversity (SD) are considered and the bit error rate (BER) performance for four following diversity schemes are compared: (1) SS diversity with MRC and antenna diversity with SD; (2) SS diversity with SD and antenna diversity with MRC; (3) MRC of both SS diversity and antenna diversity; (4) SD of both SS diversity and antenna diversity. It is shown that antenna diversity with MRC and SS diversity with selection has a performance very close to that of antenna diversity and SS diversity both with MRC. This revised version was published online in July 2006 with corrections to the Cover Date.     

Antenna Array Structures Effect on Water-Filling Capacity of Indoor NLOS MIMO Channel

1 Introduction Digital communication using MI MO has recently e-merged as one of the most significant technical break-throughs in modern wireless communications .Foschini ,Telatar and others saythat the capacity can beincreasedlinearly with the mini mum antenna numbers of thetransmitter and receiver if the scattering environment isrich and there is no correlation between the antennapairs at the transmitter and the receiver[1 ~2]. Toachieve these capacities coding techniques such asBLAST an…     

An ultrawide-bandwidth tapered resistive TEM horn antenna

A novel stable beamwidth, ultrawide-bandwidth low-scattering antenna is presented. This antenna is a modified version of the conducting slotline bowtie hybrid (SBH) antenna with resistive sheets (Rcards) introduced into the guiding structure design. Since the resistive sheets can attenuate creeping wave fields, much smaller rolled edges are needed in the Rcard SBH antenna. Moreover, due to the Rcard's partially transparent nature with respect to electromagnetic fields, the radar cross section (RCS) associated with this new antenna is smaller than the original conducting rolled edge one. By employing an optimization process based on the concept of the genetic algorithm, one can easily design the Rcard SBH antenna to obtain a very stable antenna beamwidth and phase center in both the E- and H-planes across the entire operating frequency bandwidth. Because of its constant beamwidth, low RCS, and broad-band features, the Rcard SBH antenna is an ideal antenna for many applications such as a compact range feed. Calculated and measured results are presented to demonstrate the performance of this new antenna     

Controlling resonance frequencies in antennas to achieve wideband operation

A novel antenna design method for controlling resonance frequencies is presented. This method can be realised by simply inserting a spiral inductance and a gap capacitance into a conventional loop-type antenna, and this technique remarkably enhances an impedance bandwidth without increasing the antenna size. The proposed antenna has been designed to have 530 MHz (975?1505 MHz) and 150 MHz (2410?2560 MHz) dual bands (VSWR = 2.5), and can be effectively used as an internal antenna for global system for mobile communications (GSM) and Bluetooth bands. These wideband characteristics provide a critical advantage because the shift of an antenna operation frequency increases when it is near various other components.     

基于最大比合并的MIMO分集系统递增天线选择算法

MIMO分集系统天线选择技术可以在不增加系统射频链路的情况下,达到与全天线几乎相同的分集增益.针对发送端采用最大比发送,接收端采用最大比合并的MIMO分集系统,提出了一种递增天线选择方法,每次增加一根天线,并使得它与已选出的天线结合起来具有最大的信噪比增益.相对于对所有可用天线集进行遍历的最优算法,它减小了需要搜索的范围和每次搜索的计算量,降低了复杂度;相对于功控天线选择算法,它考虑了新增天线与已选出天线集之间的相关性,改善了性能.仿真结果表明,在误比特率、信道容量和信噪比增益方面,此算法和最优算法性能相近,且不随可用天线数和选出天线数的改变而改变.     

一种应用于三频GPS的宽频带单馈电天线设计

为了实现全球定位系统（global positioning system,GPS）天线小型化并提高其性能,提出了一种新型的三频段GPS宽频带单馈电背腔天线,可在1176.45 MHz（L5）、1227.60 MHz（L2）和1575.42 MHz（L1）三个GPS频段下工作。通过在一端馈送交叉型行波天线并在另一端添加负载,来实现提出天线的右旋圆极化（right-hand circular polarization,RHCP）,且配有弯折线散热器。天线尺寸仅为120×120×29 mm3。仿真和实际测量结果显示,提出的单馈电天线无需使用复杂的馈电网络或双馈结构便可提供宽阻抗带宽（VSWR<2）、低轴比（AR）（<2 dB）和高RHCP增益（>4 dBic）。     

The dielectric wedge antenna

A new modification of the TEM-horn antenna has been developed for ground-penetrating radar (GPR) applications. The antenna is based on a dielectric wedge, and thus, was named the dielectric wedge antenna. Tapering of the metal flairs has been used to match the antenna to the ground and to reduce the late-time ringing. The finite-difference time-domain model of the antenna has been created to investigate physical processes within the antenna and to optimize its performance. The dielectric wedge antenna has shown a superior (in comparison with the TEM-horn) performance by radiation in different types of the ground and has been used in a novel antenna configuration within a GPR system, which is dedicated for landmine detection.     

Broadband Multiple Input Multiple Output antenna for sub-6-GHz 5G communications

This paper presents the design of a miniaturized broadband monopole antenna for 5G and Wireless Local Area Network (WLAN) applications in mobile handsets. The proposed monopole evolved from a rectangular geometry of size 12 × 5 mm. The slot and stub loading techniques are used to improve the impedance matching offered by the antenna. Furthermore, bandwidth broadening is achieved using lumped elements loaded onto the aperture of the antenna. The proposed miniaturized antenna exhibits a measured impedance bandwidth of 63.6% (3.0–5.8 GHz) covering the 5G spectrum allocations under sub-6 GHz and the WLAN services. The antenna elements are replicated along the sides of the mock mobile handset PCB to study the functionality of the eight-element MIMO antenna. The prototype MIMO antenna fabricated and tested in the laboratory offers a peak gain of 3 dBi and total efficiency greater than 72%. Owing to miniaturization, the spatial distribution of the antenna element provides a low envelope correlation (ECC) of less than 0.2 and good diversity gain (DG) greater than 7.8 dB. In addition, the mean effective gain (MEG), channel capacity loss (CCL), multiplexing efficiency (ME), and total active reflection coefficient (TARC) are evaluated and presented. The estimated MIMO metrics are within the desired range of operation and hence make the antenna suitable for a complex propagation environment. The prototype antenna is developed on a thin microwave laminate with low-loss characteristics and tested under laboratory conditions. The outcomes indicate that the proposed eight-element antenna can be applied to 5G MIMO communications.     

平面隙缝阵列天线的宽带电磁散射特性分析

 针对主动雷达导引头对防空导弹武器系统制导雷达站检测与识别的需求,研究了平面隙缝阵列天线的宽带电磁散射特性.将天线的电磁散射机理与目标高频散射中心理论相结合,建立了天线的电磁散射模型,分别采用矩量法和物理光学法计算天线的模式项散射场和结构项散射场,并从理论上证明了天线散射中心的客观存在,分析了隙缝阵列天线的散射中心分布特征.最后对不同视角下天线的高分辨距离像进行了仿真,为进一步理解天线的电磁散射机理、分析其宽带电磁散射特性、以及采用高分辨率成像技术对雷达站进行检测与识别奠定了基础.     

Modified planar inverted F antenna

The design of a modified planar inverted F antenna (PIFA) which is more compact (antenna length <λ₀/8 and antenna height <0.01 λ₀) and has a much wider antenna bandwidth (greater than 10 times that of a simple PIFA) is demonstrated. The reduction in antenna length is achieved by meandering the radiating patch, while the enhanced bandwidth with low antenna height is obtained using a chip-resistor load in place of the shorting post. A typical design of the modified PIFA in the 800 MHz band has been implemented, and experimental results are presented and discussed     

Spectral efficiency of distributed antenna system with random antenna layout

The downlink capacity potential of a distributed antenna system (DAS) with random antenna layout is investigated. A low complexity sub-optimal power allocation scheme among transmit antennas is proposed. Simulation results show that with the same antenna density DAS outperforms a co-located antenna system (CAS) in terms of average and outage spectral efficiency.     

Gain improvement of planar-printed broadband end-fire antenna

A broadband high-gain planar-printed end-fire antenna is presented for microwave imaging application. The proposed antenna consists of a conventional Vivaldi antenna (CVA) with slot edges (SEs) and a planar phase compensation lens (PCL). Taking into account the actual phase error along E-plane direction at antenna aperture, a more precise and detailed analysis for the printed antenna with PCL is carried out. The PCL with specific layout of rectangular patches is utilised to enhance antenna gain especially at high frequencies, while the SE technique is employed to further improve directivity at low frequencies. The final design combining PCL and SE develops an expected high-flat-gain Vivaldi antenna over the entire operating range. The CVA and the proposed antenna are fabricated and measured. The measured results agree with the simulated ones well. The proposed antenna provides a high gain of 10–11.7 dBi in the range, which corresponds to a gain increase of 0.9–3.2 dBi compared to the CVA.     

MOM结合AWE技术分析高斯曲线天线

将最佳形状对称天线近似为高斯曲线天线 ,用矩量法 (MOM)计算电流分布 ,并运用渐近波形估计 (AWE)技术快速预测高斯曲线天线的宽带响应 ,得到天线的输入阻抗、方向图和增益。计算结果表明 ,高斯曲线天线是一个很好的辐射器 (或接收器 ) ,它可以进一步降低副瓣 ,增强在天线对称轴方向的辐射 ,从而可以得到较直线天线高的增益。     

带有开口谐振环引向器的新型端射天线设计

设计一种带有开口谐振环(SRRs)引向器的新型端射天线。天线由反射板、地板、辐射单极子和开口谐振环组成。天线的反射板结构使天线在低频处阻抗匹配,有效地提高了天线带宽;用六对开口谐振环结构作为天线的引向器,很好地实现了天线的高增益。仿真和实测结果表明,天线阻抗带宽达到73.7%(2～4.21 GHz),增益为4.3～10.3 dB;在天线的带宽内,天线的辐射方向图稳定,设计的天线满足S波段无线通信领域的需求。