A novel single feed frequency and polarization reconfigurable microstrip patch antenna

In this paper, a novel single feed frequency and polarization reconfigurable microstrip patch antenna is presented. This antenna mainly comprises of a corner truncated square patch with a rectangular ring slot, eight PIN diodes and six conductive pads. Four PIN diodes are placed symmetrically in the rectangular ring slot to bridge the gap and to switch the frequency between WLAN bands resonating at 5.2G Hz and 5.8G Hz. Four PIN diodes connect the corner truncated square patch to parasitic triangular conductors. PIN diodes are used to switch the polarization between linear, right hand circular and left hand circular at each frequency. When compared to conventional patch, the proposed design provides a size reduction of 12% at 5.2G Hz, and 30% at 5.8G Hz. The simulated reflection coefficient and radiation patterns are presented and compared with the experimental data. This antenna finds applications for modern wireless communication system.     

A dual-band multiple-input multiple-output microstrip antenna with metamaterial structure for LTE and WLAN applications

A method to enhance the gain of microstrip dual-band multiple-input multiple-output (MIMO) antenna using partially reflective surface (PRS) layer is introduced and investigated in this paper. The proposed antenna consists of two FR4 substrates. The lower substrate has two radiating patches with parasitic elements that are supplied independently and create the MIMO property of the antenna. The upper substrate which is known as superstrate is arrays of PRS unit cells. The PRS layer printed on either side of a dielectric substrate and causes the antenna gain to increase in both frequency bands. The proposed antenna is appropriate for LTE (2.4–3.1 GHz) and WLAN (5.1–5.8 GHz) applications. The measured values of S₁₁ and S₂₂ parameters of the antenna are less than −10 dB and its FBR and gain are 12.5 dB and 5dBi, respectively. The average half power beam-width (HPBW) is roughly 108^○.     

应用于WLAN的小型微带天线

为了满足手机无线局域网(WLAN)通信技术的要求,设计了一个三频段单极子贴片天线,通过2个L形支路产生双频辐射。并用软件对该天线进行仿真优化,实现了2.4 GHz、5.2 GHz和5.8 GHz三频段的同时工作,而且该天线结构简单,由L形贴片组合形成,体积小,所占面积为14.5 mm×16.5 mm。仿真结果表明,该天线的尺寸和性能可以在手机WLAN通信系统得到良好的应用     

Dual-band polarization and frequency reconfigurable antenna using double layer metasurface

In this paper, a polarization and frequency reconfigurable antenna with double layer metasurface, responsible for frequency and polarization reconfiguration respectively, is proposed. This antenna could operate in linear polarization in 4 GHz and circular polarization in 5 GHz band. By rotating the frequency reconfiguration metasurface, the linear polarization (LP) operating frequency can be continuously changed from 4 GHz to 4.35 GHz (8.4%) with circular polarization operating frequency around 5 GHz unchanged. Moreover, polarization of the whole antenna at 5 GHz can be reconfigured to linear polarization (LP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP) by rotating polarization reconfiguration metasurface, the 3 dB axial ratio bandwidth is 5.0–5.2 GHz (4%). In all states, gain of the antenna achieves 5 dBi.     

Reconfigurable dual-band circularly polarized microstrip patch antenna for wireless applications

A new design of reconfigurable single-feed circular patch microstrip antenna for dual-band circular polarization application is proposed. The dual-band functionality is realized through incorporating cross-slots of equal slot length in the circular patch and utilizing two PIN diodes to switch the slots on or off. A pairs of tuning stubs are used to tune the circular polarization performance. The design process is presented and good results were obtained.     

一种双频左/右旋圆极化可重构环形缝隙微带天线

设计了一种频率比为1.9的双频左/右旋圆极化可重构环形缝隙微带天线,其在高频段和低频段分别工作于线极化和圆极化状态。在该天线中,环形缝隙和相互正交的四个缝隙臂将接地面分为五部分,缝隙臂上跨接两对PIN二极管开关和隔直电容。通过二极管开关的控制,天线在低频频率上可实现左/右旋圆极化的切换,在高频频率上则可保持其线极化性能不变。实验结果表明,天线在1.6 GHz的低频段上具有12.5%的3 dB轴比带宽,在3.06 GHz的高频段上其–10 dB阻抗绝对带宽为100 MHz,成线极化状态,辐射方向图近似不变。     

A reconfigurable wideband MIMO antenna combines RF energy harvesting

This article introduces a novel and groundbreaking approach combining multiple-input-multiple-output (MIMO) technology with radio frequency (RF) energy harvesting. The proposed antenna consists of two semi-circular monopole antenna components, optimized with dimensions of 89 × 51.02 × 1.6 mm³, that share a common ground plane to achieve MIMO characteristics. A series of split-ring resonators on the ground plane significantly enhances the isolation between the two radiating components. Band-notched features are performed in the 3.5 GHz WiMAX and 5.5 GHz WLAN bands through modified C-shaped slots in the radiating patch and two rectangular split-ring resonators serving as parasitic devices near the feed line. The reconfiguration of band-notching is made possible by controlling the modes of the embedded PIN diodes. The two antenna elements maintain mutual coupling below −18 dB from 1.5–13 GHz, achieving an impressive 158.62% impedance bandwidth. The antenna's efficiency and gain experience significant drop, indicating effective interference suppression at the center frequencies of the notch bands, and its performance in MIMO systems is assessed through parameters including envelope correlation coefficient, port isolation, radiation patterns, efficiency, gain, and diversity gain. The simulated properties of the designed antenna closely align with the measured outcomes, demonstrating its reliability and consistency. Moreover, the article evaluates the antenna's potential for RF energy harvesting, achieving a maximum harvested energy of 4.88 V. This proposed antenna can be used in multiple applications, like wideband, band-notching MIMO, and RF energy harvesting. This proposed antenna is an efficient, reconfigurable wideband MIMO antenna with novel RF energy harvesting capability.     

一种圆极化可重构微带天线的设计

对圆弧寄生单元微带天线进行了理论分析,设计了一种圆极化可重构的圆形微带天线。该天线通过电控开关控制圆弧寄生单元的状态,从而实现左、右旋圆极化的转换。并利用仿真软件HFSS13.0对天线的特性进行了仿真验证。结果表明,在天线回波损耗S11<–10 dB时,该天线在频段为2.38~2.51 GHz,3 dB轴比带宽为30 MHz,且最大辐射方向处正交极化差达20 dB以上。天线的整体辐射性能良好,且结构简单易于实现,很容易在低频段匹配到50,能够满足WLAN在2.4 GHz频段的要求。     

一种适用于极化捷变天线的可重构射频网络设计

介绍了一种适用于极化捷变天线的可重构射频网络.该射频网络由一个两路可重构Wilkinson功率分配器和两个45°/135°可重构移相器构成,通过控制PIN二极管的偏置电压,可实现两种单路（1:0和0:1）传输模式和三种两路（1:1,1:j和j:1）传输模式,即五种不同的工作模式切换.实测结果表明:该可重构射频网络在单路传输模式（相对带宽6.7%）下的插入损耗小于1.5 dB,输入端口的回波损耗大于12.1 dB;在两路传输模式（相对带宽4.3%）下的输出端口间隔离度大于23.6 dB,相位差为3.5~5.4°（1:1模式）和92.6~97.4°（1:j和j:1模式）,相位误差小于7.4°.     

共面波导馈电的频率可重构印刷单极子天线

提出了一种间接改变天线辐射体长度的方法。该方法通过改变天线馈线中地导体的长度,间接地改变天线辐射体的长度,有效避免了有源开关对天线辐射性能的影响。为验证此方法,设计了一个共面波导馈电的频率可重构印刷单极子天线,该天线利用PIN二极管来改变馈电端地的长度。实验结果表明:控制开关的工作状态,可使天线的谐振频率发生明显的变化。相应的中心频率分别为1.9 GHz和2.3 GHz,相对阻抗带宽分别为20.8%和17.2%。     

A circularly polarized slot antenna for high gain applications

A coplanar waveguide fed slot antenna for wideband circular polarization is designed and experimentally validated. The rectangular slot is excited using a stepped feed line terminated on a circular disc shaped tuning stub. To obtain circular polarization, inverted L-shaped strips are attached to the ground plane at the opposite corners while a rectangular slit is cut in the circular disc. The combined bandwidth (3-dB axial ratio and 10 dB impedance matching) achieved is 48% (4.35–7.1 GHz) under simulation and 40% (4.75–7.1 GHz) in measurement. The gain of the antenna is next enhanced by the application of a double layered square loop frequency selective surface. The frequency selective surface is used as a reflector placed beneath the antenna at an optimum distance. An improvement of about 4 dB is seen in the measured peak gain over most of the operating band. Experimental results are presented to characterize the antenna and the frequency selective surface and they are found to be in good agreement with the simulated results.     

左/右旋圆极化可重构微带天线

设计了一种左/右旋圆极化可重构的微带天线。在矩形微带贴片的两条边上增加枝节,贴片与枝节通过PIN 二极管开关连接,通过控制PIN 二极管的通断来改变正交模式的相位差,使天线在同一个馈电点上可实现左旋圆极化（LHCP）和右旋圆极化（RHCP）的重构。该天线在（2800±10）MHz 的频率范围内驻波比小于2,轴比小于3dB。仿真结果与测试结果均验证了该方案的可行性。     

一种应用于WLAN/WiMAX的双频微带天线

提出了一种适用于WLAN/WiMAX的小型化双频微带天线。在矩形辐射贴片表面加载2/5形缝隙,改变矩形辐射贴片表面电流路径,使电流有效路径增加,实现天线的双频特性。通过电磁仿真软件HFSS 15.0对天线模型进行仿真分析。结果表明,天线可同时工作于WiMAX2.60 GHz和WLAN5.15 GHz频段,低频段和高频段的相对带宽分别为4%(2.53~2.64 GHz)和6%(5.14~5.48 GHz),最大增益分别为4.47 dB和1.35 dB,能够满足WLAN和Wi MAX的通信需求。天线整体辐射性能良好、结构简单、容易集成于前端电路。     

Reconfigurable Circularly Polarized Microstrip Antenna on a Slotted Ground

A compact square patch antenna with reconfigurable circular polarization (CP) at 2.4 GHz is proposed. Circular polarization is generated by an arc‐shaped slot on the ground plane. In order to switch the CP orientation, the current flow direction of the patch is reconfigured via the PIN diodes mounted on the slot. As the slot and bias circuit are not placed on the patch side, the proposed antenna radiates a CP wave without alteration in the main beam direction. From the experimental results, the impedance and CP bandwidths of the proposed antenna have been demonstrated for up to 80 MHz and 25 MHz, respectively.     

双极化方形微带天线的阻抗特性

在方形微带贴片的相邻两边电可以辐射双极化波。文中结合平面电路技术,腔模理论,用Ｇｒｅｅｎ函数法导出了双边馈电方形微带天线输入阻抗与互阻抗的计算公式,分析了Ｘ波段双极化方形贴片天线输入阻抗,Ｓ参数和电压驻波比在谐振频率附近的变化情况,以及馈电点位置与宽度和εｒ对这些特性参数的影响。文中的计算方法可靠而简捷,可用于此类天线的设计,这种天线容易形成阵列结构,并易于有源集成。     

Design of a compact U-shaped slot triple band antenna for WLAN/WiMAX applications

This article presents a small, low-profile planar microstrip antenna that is applicable for both WLAN and WiMAX applications. The goal of this paper is to design an antenna which can excite triple-band operation with appreciable impedance bandwidth to combine WLAN/WiMAX communication specifications simultaneously in one device. The designed antenna has a compact size of 10 × 26 mm². The proposed antenna consists of an inverted U-shaped slot radiator and a defected ground plane. Overall the design method and parametric study found appropriate dimensions, which provides three distinct bands I from 2.40 to 2.52, II from 3.40 to 3.60 and III from 5.00 to 6.00 GHz that covers entire WLAN (2.4/5.2/5.8 GHz) and WiMAX (2.5/3.5/5.5) bands. Finally, a prototype antenna was fabricated and experimentally characterized to verify the design concept as well as to validate the simulation results. Thus the simulation results along with the measurements show that the antenna can simultaneously operate over WLAN and WiMAX frequency bands.     

Frequency notched wide slot antenna for UWB/2.4 GHz WLAN applications

A compact frequency notched microstrip slot antenna for ultra-wideband (UWB) /2.4 GHz-band wireless local area network (WLAN) applications is proposed. The antenna is similar to a conventional microstrip slot antenna; however, by introducing a cross wide slot and a meandered-slotted stub, both compact size and frequency notched function can be achieved. It has been studied both numerically and experi- mentally for its impedance bandwidth, surface current distribution, radiation patterns, and gain. As will be seen, an operation bandwidth of over 4.61 ranging from 2.39 to 11.25 GHz for return loss lower than having a frequency notched band ranging from 4.75 to 5.85 GHz has been achieved, and good radiation performance over the entire frequency range has also been achieved.     

馈电相位可调极化可重构微带贴片天线

设计了一种相位可调的极化可重构微带贴片天线.该天线采用双馈电方式工作,通过改变馈电网络中4个单刀双掷开关的导通状态在两个馈电点形成不同的相位差,从而实现左旋圆极化、右旋圆极化以及线极化之间的切换.实验结果与理论分析和仿真结果相吻合,天线实现了良好的极化重构能力.特别是不同极化状态下,天线工作频率具有良好的一致性.