一种用于微波能量传输的圆极化接收整流天线

提出了一种新颖的用于微波能量传输的圆极化接收整流天线.用内环开槽的圆环形微带天线作为接收天线,在工作频率5.8GHz时得到的轴比为1.2dB,使用肖特基势垒二极管作为整流部分.通过测量接收整流天线的能量转换效率和输出功率,证明其非常适用于移动物体间的微波能量传输.     

微波输能应用中整流天线阵列接收效率的研究

整流天线阵列是微波无线能量传输系统的重要组成部分,其接收和转换效率关系到能量无线传输的成败。在5.8 GHz频段采用矩形、圆形和三角形3种微带贴片单元,分别以发射天线阵列最大口径效率和接收天线阵列最高接收效率为目标进行优化,仿真计算了各天线阵列对空间电磁来波的接收效率。结果表明,天线单元形状会影响整流天线阵列的接收效率,相对于按发射天线阵列最大口径效率设计,以最高接收效率优化排布的整流天线阵列,对空间电磁来波的接收效果较好。     

家用小功率电器的微波无线供电研究

智能家居热度不减,而家用电器的无线供电也是人们研究的热点.微波无线能量传输具有定向性好、传输距离远的特点,在无线输电领域具有广泛的研究前景.通过仿真计算确定印制偶极子天线的基本参数,完成了偶极子天线的设计和制作.以印制偶极子天线为微波的接收天线,结合椭圆滤波器和整流二极管等制作的整流电路,完成了2.45 GHz频率下的微波输电实验.实验获得了72.7％的RF-DC整流效率及197 mW的直流能量,为家用电器的无线供电提供了一种可供探索的方式.     

RFID芯片电源恢复问题分析

RFID(Radio Frequece Identification)是一种利用反射波进行通信的远程识别技术.RFID标签为无源标签,标签芯片工作所需的能量需要从标签天线所接收的微波信号中进行恢复.为了获得尽量远的工作距离,天线的输出阻抗需要与芯片的输入阻抗相匹配,整流部分必须有较高的能量转换效率.本文研究了电子标签所能接收到的微波功率随工作距离的变化,以及RFID芯片电源恢复部分的输入阻抗及整流效率等问题.通过仿真分析所获得的结果可以为芯片电源恢复部分的设计及天线设计提供参考.     

一种5.8GHz新颖混合结构的整流天线

整流天线决定了微波无线输电效率的高低。为了克服微带贴片整流天线需要钻孔,不利于大规模生产的问题,提出了一种新型5.8GHz混合结构的整流天线,接收面积大的矩形微带贴片构成接收天线,过渡到具有平行结构的共面带线,二极管和电容可方便地摆放在共面带线的两侧,避免了钻孔。试验表明该接收系统整流转换效率达到了78.2%,验证了设计的可行性。     

一种2.45GHz高效微带贴片接收整流天线

微波接收整流天线是微波无线输电的关键技术之一,微带贴片天线,非常适合运用于微波飞机、高空平台等场合。设计了一个输入阻抗为50Ω的微带贴片接收整流天线,系统的总体转换系统可达到70.2％。     

一种高效环境WiFi能量收集系统

针对无线传感器系统高效率供电的问题,提出通过射频收集能量并转换为电能的方式将能量提供给无线传感器系统使用的方法。重点研究一款高效的环境WiFi能量收集系统,主要包括天线和整流电路优化设计2大部分。天线由2×2微带天线阵列组成,主要负责捕获环境中2.4 GHz WiFi信号,提高接收天线的灵敏度。整流电路设计基于Greinacher倍压电路,通过改变倍压电路参数或元器件的方式来提高转换效率即可以高效地转换能量。通过调整天线阵列和整流电路的参数,当输入功率在-35~-10 dBm时,能量收集系统的转换效率可以达到最佳状态。在特定的频带进行仿真测试,能量收集系统接收天线距离WiFi路由器2.3 m时,输出整流电压为1 089 mV。实验结果表明,能量收集系统可以有效地从周围的WiFi信号中收集能量。     

整流天线技术及应用

整流天线能把空间的微波能量转化为直流能量。本文分析了它的工作原理,介绍了几种理论分析方法和关键指标测试方法,并进一步分析研究了检波二极管微波/直流转换效率随负载和输入功率的变化关系。最后,列举了整流天线技术在工程技术领域已取得的成果并分析了它的应用前景。     

一种用于无线输能的2.45 GHz微带贴片整流天线

为了提高大信号输入下整流天线的整流效率,利用Ansoft Designer仿真软件,设计制作了一种工作在2.45 GHz的微带整流天线,接收天线采用二元串联微带矩形贴片阵列,单元贴片之间引入两个短枝节以调节方向图指向;整流电路采用二极管串联双管倍压电路。实验结果与仿真结果二者吻合良好,实测得到输入功率为100 mW时,微波-直流转换效率达到64%,同单管并联电路相比,大大提高了整流电路的输入功率,使整流天线的实际转换效率更高。     

一种实用线极化矩形微带贴片接收整流天线的仿真设计

太空电站以及微波输电被认为是解决人类能源危机的一个切实可行的方案之一，本文介绍了微波接收整流天线的原理，设计了一种实用、尺寸简洁的线极化矩形微带贴片接收和整流天线，通过高频电磁仿真软件Ansoft Designer V1．0仿真表明该系统中二极管的转换效率超过70％，系统总转换效率大于63％，验证了该设计在理论和实际上的可行性。     

5.8-GHz circularly polarized dual-rhombic-loop traveling-wave rectifying antenna for low power-density wireless power transmission applications

This paper reports a right-hand circularly polarized (RHCP) high-efficiency traveling-wave rectifying antenna (rectenna) designed in a coplanar stripline (CPS) circuit that is etched on a Rogers Duroid 5870 substrate with /spl epsiv//sub r/=2.2 and 20-mil thickness. A 4 /spl times/ 1 traveling-wave array of RHCP high-gain dual-rhombic-loop antennas (DRLAs) and a reflecting plane are used to provide highly efficient RF-to-DC conversion in the presence of lower power densities regardless of the rectenna's broadside orientation. The DRLA array has a circularly polarized antenna gain of 14.6 dB with a 2:1 voltage standing-wave ratio bandwidth of 17% and a better than 3 dB axial ratio fractional bandwidth of 7% centered about 5.8 GHz. The rectenna achieves 82% RF-to-DC conversion efficiency at 5.8 GHz and uses a low-profile CPS band-reject filter to suppress the re-radiated second harmonic by over 14 dB. The rectenna operating at low power density should have many applications when the transmitting power is low and/or the transmission distance is long.     

新型CPS型低通滤波器在整流天线中的应用

提出了一种新型共面带状线(CPS)低通滤波器,并将其用于圆极化整流天线中。该滤波器实现了小插损、宽阻带。通过宽带巴伦转换,实验测得衰减大于15dB的阻带带宽达到10.3GHz,5.8GHz处插入损耗为1.62dB,在11.6GHz和17.4GHz处插入损耗分别为30.3dB和26.3dB,与仿真结果吻合较好,有效地抑制了二次和三次谐波。将该低通滤波器应用于圆极化整流天线中,测得高达72.3%的RF-DC(Radio Frequency-Direct Current)转换效率,该整流天线可作为无线输能系统的接收部件。     

用于整流天线的口径耦合圆极化微带天线的设计与实验

提出了一种用于整流天线的新型圆极化微带天线形式，此天线采用单端口径耦合馈电，易与整流电路集成和匹配。利用电磁场仿真软件分析了天线参数对天线性能的影响，设计并加工了一个圆极化天线单元。设计值和实验值较吻合，实验结果表明该天线在10．25GHz具有良好的圆极化特性：在最大方向上圆极化轴比为0．3dB，3dB圆极化带宽达到160MHz，驻波比小于2的带宽达到800MHz。     

具有谐波抑制功能的共面波导轻薄整流天线

为解决对无人机、平流层飞艇等空中移动目标无线输能时机载接收端整流天线质量大,占居飞行器有效载荷多的难题,设计了一种具有谐波抑制功能的共面波导轻薄圆极化整流天线。该整流天线采用集中式整流方式,通过将整流电路直接集成在微带天线接地板上,实现了质量轻,尺寸小,剖面低,易共形的圆极化整流天线。该天线工作在5.8 GHz,采用共面波导耦合馈电,并在馈线上直接加载共面波导谐振结构进行谐波抑制,具有较宽的工作带宽。整流电路采用倍压整流形式,利用贴片电容作为直通滤波器进行直流滤波,电路结构简单。该整流天线结构紧凑,质量仅6.28 g,剖面厚度0.5 mm,最佳整流效率63.84%,测试结果与仿真结果吻合良好,验证了该设计的可行性。     

Circularly polarised truncated-corner square patch microstriprectenna for wireless power transmission

A circularly polarised rectenna using a truncated-corner square-patch microstrip antenna has been developed for wireless power transmission at 5.8 GHz. The gain and axial ratio achieved were 8.5 dBi and 0.5 dB at 5.82 GHz respectively. A GaAs Schottky barrier diode was employed for microwave to DC conversion with a maximum conversion efficiency of 60%     

Low profile multiband rectenna for efficient energy harvesting at microwave frequencies

This paper presents the design and development of a multiband rectenna for ambient RF energy harvesting. The proposed rectifying antenna consists of fractal-based geometry to obtain GSM 0.9 GHz (0.8–1.2 GHz), GSM 1.8 GHz (1.6–2.1 GHz), WLAN 2.5 GHz (2.2–2.8 GHz), Wi-MAX 3.5 GHz (3.1–4.0 GHz), WLAN 5.5 GHz (5.3–6.4 GHz) and 7.35 GHz (7.0–7.8 GHz) resonating bands. The designed sensing antenna is low profile, lightweight and small in size with two circularly polarized bands at frequencies 1.8 and 2.5 GHz. In the proposed rectenna, a dual-stage voltage doubler rectifying circuit is utilized for converting surrounding RF signals into DC power. A matching network is connected between the fractal antenna and the rectifying circuitry for realizing a good impedance matching between them. To verify the proposed design, a prototype rectenna is fabricated and measured results are compared with the simulated results. The proposed rectifier provides an RF to DC conversion efficiency of 78%.     

Low-profile circularly polarized rectifying antenna for wireless power transmission at 5.8 GHz

Portable devices operating without batteries are sometimes desired in wireless applications such as RFID (Radio Frequency Identification) and telemetry. A novel circularly polarized shorted annular ring-slot rectenna (rectifying antenna) on a 0.5 mm thick flexible microwave laminate is proposed for the powering of these devices. Output dc voltage of 1.3 V and axial ratio of 1.5 dB were measured when 32 dBm microwave power was transmitted at 5.8 GHz over a distance of 2 m. Comparing the results with a rectenna designed on a thick rigid laminate, similar performance was observed.     

C波段高增益圆极化微带天线阵的研制

论述了圆极化微带天线阵的设计方法。以工作频率为5.8GHz,32单元圆极化微带天线阵为研究对象,设计出了与馈电网络为一体、具有圆极化特性的微带天线阵,从而解决了圆极化微带天线阵馈电网络较为复杂、工程实现较为困难这一问题。实验结果表明该天线阵具有良好的圆极化特性,进而说明了该方法是有效可行的。     

具有谐波抑制功能的圆极化整流天线设计

设计了一款新型的具有谐波抑制能力的圆极化整流天线。在圆环缝隙天线的中心挖圆形孔,控制天线的谐振频带与抑制高次谐波。在缝隙的内边缘开两个半圆形槽,缩减天线的尺寸并获得圆极化辐射。倍压整流电路有效地提高了整流天线的输出直流电压。仿真结构表明,天线谐振带宽(VSWR＜2)为17.6％,圆极化带宽(AR＜3 dB)达到3.7％。整流电路在0 dBm的输入功率时,能达到59％的整流效率和1.7 V的直流输出电压。该整流天线可作为无源射频识别(Radio Frequency Identification,RFID)标签的整流天线。     

5.8-GHz circularly polarized rectifying antenna for wireless microwave power transmission

This paper reports a new circularly polarized (CP) high-gain high-efficiency rectifying antenna (rectenna). The CP rectenna can be rotated and still maintain a constant dc output voltage. The high-gain antenna has an advantage of reducing the total number of rectenna elements to cover a fixed area. The rectenna is etched on Rogers Duroid 5870 substrate with /spl epsi//sub r/=2.33 and 10 mil thickness. A high-gain dual-rhombic-loop antenna and a reflecting plane are used to achieve a CP antenna gain of 10.7 dB and a 2:1 voltage standing-wave ratio bandwidth of 10%. The rectenna's pattern has an elliptical cross section with orthogonal beamwidths of 40/spl deg/ and 60/spl deg/. The rectenna circuit has a coplanar stripline band-reject filter that suppresses the re-radiated harmonics by 20 dB. A highly efficient Schottky diode is used for RF-to-dc conversion with an efficiency of approximately 80% for an input power level of 100 mW and a load resistance of 250 /spl Omega/.