基于人工磁导体的超宽带高增益天线设计

随着无线通信环境的日益复杂,为了提高天线抗干扰能力,满足现代无线通信的大容量、宽带化和高增益的要求,文章提出了一款基于人工磁导体的宽带高增益天线。该天线采用共面微带线设计,辐射体为梯形贴片,其渐变的结构有利于获得较宽的阻抗带宽。同时,天线在背向引入宽带人工磁导体(AMC)作为反射板以实现定向辐射,并在辐射方向上辅以寄生超表面单元,进一步改善天线阻抗匹配,抑制表面波损耗。最终,天线实现了超宽带化和高增益。仿真结果显示,天线工作带宽达到94.8%,可以满足移动通信、无线通信以及卫星通信要求。此外,天线在工作带宽内平均峰值增益达到9.5 dBi。     

Tm3+掺杂硫卤玻璃光纤的中红外增益特性研究

采用高温熔融淬冷法制备了1% Tm³⁺掺杂的 72GeS₂-18Ga₂S₃-10CsI(GGSI)硫卤 玻璃,测试了样品的折射率、吸收 光谱和800nm激光泵浦下的中红外荧光光谱,利用Judd-Ofelt和Fut chbauer-Ladenburg(FL)理论分析计算了Tm³⁺在GGSI玻 璃中的自发辐射几率、荧光分支比、辐射寿命、吸收截面、发射截面等光谱参数,进而建立 了Tm³⁺的四能级粒子 数速率-光功率传输方程模型,模拟计算Tm³⁺掺杂GGSI玻璃光纤中红外3. 73μm波段的增益与掺杂光纤长度、泵浦功 率和信号功率的关系。模拟结果显示,硫卤玻璃基掺铥光纤具有较高的信号增益和较宽的中 红外增益谱,泵浦功率为1000mW 时,最大小信号增益值达到30dB,20dB增益带宽达到180nm,同时也存在合适的泵浦功率 和光纤掺杂长度以期获得最佳信号增益。表明Tm³⁺掺GGSI硫卤玻璃光纤可作为中红外 3.73μm波段放大的理想增益介质。     

一种新型超宽带高增益维瓦尔第天线的设计与性能研究

设计了一种新型超宽带高增益维瓦尔第天线，在传统对踵维瓦尔第天线的两端均增加弧形辐射结构，从而提高天线的低频辐射带宽；在天线辐射方向添加一块渐变型介质板，将天线正反两面的表面电流限制在天线辐射方向，既可以矫正E面方向图的增益峰值偏移角度，也可以提升天线辐射强度。实测结果显示：1.6-20GHz频段内的天线VSWR均比小于2，倍频带宽高达12.5，增益为1.5-11.1d B，并且该天线的E面方向图对称性好、交叉极化比小，易于设计、成本低廉，在超带宽、高增益的定向辐射天线方向拥有较高的研究意义和应用价值。     

NH3等离子体处理钝化层致Ge MOS界面特性的改善

制备了以TaYON作为钝化层,以HfTiON作为高k栅介质的Ge MOS电容。研究了NH₃和N₂等离子体处理TaYON对界面特性的影响。结果表明,N₂和NH₃等离子体处理可以有效改善器件的界面及电性能,其中,NH₃等离子体处理的效果更好,可获得更高的k值(25.9)、更低的界面态密度(6.72×10¹¹ eV-1·cm-2)和等效氧化物电荷密度(-9.43×10¹¹ cm-2),以及更小的栅极漏电流(5.18×10-5 A/cm²@V_g=1 V+V_fb)。原因在于NH₃等离子体分解产生的N原子或H原子以及NH基团能有效钝化界面附近的悬挂键和缺陷态,防止GeO_x低k界面层的形成,N原子的结合也增加了介质的热稳定性。     

（英）基于0.13 μm SiGe BiCMOS 工艺的在片背腔贴片天线

本文提出了一款基于0.13-μm SiGe BiCMOS工艺设计、加工的340-GHz在片背腔贴片天线。辐射贴片位于AM金属层,带状线馈线置于LY金属层并通过连接AM金属层和LY金属层的金属化通孔对辐射贴片馈电。通过设计连接AM金属层和M1金属层的金属化通孔形成谐振腔体展宽了天线阻抗带宽、提升了天线辐射性能。天线的仿真阻抗带宽(S₁₁≤-10 dB)为9.2 GHz(335.6-344.8 GHz)。天线在340GHz处的仿真增益为3.2 dBi。天线的整体尺寸为0.5×0.56 mm2。     

热处理对掺Er3+碲酸盐玻璃近红外发光性能的影响

采用高温熔融冷却法和原位受控析晶法,制备了两 种Er³⁺掺杂碲酸盐玻璃及微晶玻璃。对比研究了其析晶 性能及近红外发光性能;计算了Er³⁺在玻璃与微晶玻璃中的J-O强度参数、自发辐射 概率、荧光分支比和 荧光辐射寿命;在980nm波长泵浦源下测量样品的荧光光谱,计算荧 光有效线宽、峰值受激发射截面。结果发现, 采用合理的析晶热处理制度,可以获得透明度高的Er³⁺掺杂碲酸盐微晶玻璃;析 晶热处理能够有效地提高 Er³⁺在近红外波段的发光效率和拓宽其有效发光带宽;Er³⁺掺杂85TeO₂- 10TiO₂-5La₂O₃(TTL)碲酸盐微晶玻璃较78TeO₂-17ZnF₂-5Bi₂O₃(TZBF)碲酸盐微晶玻璃在1.55μm波段增益性能更好,有望在光纤放 大器中得到应用。     

基于法布里-珀罗腔的圆极化太赫兹天线设计

为满足未来无线通信的高带宽与圆极化通信的需要,提出了一种基于法布里-珀罗腔的圆极化太赫兹天线。该天线采用准光学的波导馈电模式,对圆波导45°切槽实现天线的线-圆极化转换,采用电介质材料的部分反射面来提高天线的增益。仿真分析表明,该天线在228GHz处获得最大增益为14.4dBic,阻抗带宽(S₁₁＜-10dB)为40GHz,3dB增益带宽和轴比带宽分别为18与27GHz,三者重叠带宽为18GHz。该天线具有良好的方向性、高带宽以及在整个工作频带实现圆极化等优点,在太赫兹/毫米波无线通信中有一定的参考性与实用性。     

高k HfLaO栅介质MoS2晶体管的性能研究

比较研究了HfO₂与HfLaO栅介质多层MoS₂场效应晶体管。实验结果表明,与HfO₂栅介质MoS₂晶体管相比,HfLaO栅介质MoS₂晶体管表现出更优的电性能。电流开关比高达1×10⁸,亚阈斜率低至76 mV/dec,界面态密度低至1.1×10¹² cm-2·eV-1,载流子场效应迁移率高达1×10⁹ cm²·V-1·s-1。性能改善的原因在于镧(La)对HfO₂的掺杂形成HfLaO化合物,减小栅介质薄膜的表面粗糙度,降低缺陷电荷密度,改善了栅介质/沟道界面特性,从而减小了界面态密度,抑制了库仑散射和界面粗糙散射。最终,提高了多层MoS₂晶体管的场效应迁移率,改善了晶体管的亚阈特性。     

基于超表面的低剖面高增益圆极化天线

提出了一种基于缝隙耦合超材料表面的低剖面圆极化高增益天线,该天线由一个超材料表面和一个微带缝隙天线紧贴着组成. 通过改变超表面切角的大小来产生圆极化波,同时还可以提高天线增益和拓宽阻抗带宽. 为了验证仿真结果,制作和测量了一个大小为1λ×1λ×0.067λ(在10 GHz处)的样本天线,仿真和测量结果显示出良好的一致性. 结果表明,在整个工作带宽内天线的增益均在7.5 dB以上,最大增益达到10.5 dB,比普通缝隙天线提高了5.3 dB,阻抗带宽(S₁₁ < ?10 dB)为27.4%,轴比带宽(AR < 3 dB)达到12.3%. 因此,该天线能同时满足低剖面、圆极化、高增益等多种性能的要求,可以应用于许多领域.     

一种对拓式超宽带高增益Vivaldi天线设计

文中设计了一款结构新颖的对拓式超宽带高增益的Vivaldi天线。该天线在基板两侧引入平衡辐射臂并用通孔将它们联结起来,使天线增加了低频带宽、降低了交叉极化、减小了尺寸;在不影响带宽的前提下,通过在天线首部和尾部分别添加介质引向器和反射地板,使天线的增益得到了提高。天线测试结果表明该天线的带宽在2 GHz～20 GHz内反射系数均低于-10 dB,且天线增益最高为12.8 dBi,同时在带宽范围内,保持了良好的方向图对称性和低交叉极化水平。     

Broadband cylindrical dielectric resonator antenna excited by modified microstrip line

The impedance bandwidth of a high permittivity cylindrical dielectric resonator antenna excited by a microstrip line was significantly improved by modifying the feed geometry. The 10 dB return loss bandwidth is enhanced from 12 to 26% without much affecting the gain and other radiation properties of the antenna. Good agreement has been observed between the predicted and measured results.     

A new design approach for dual‐band patch antenna serving Ku/K band satellite communications

A printed planar antenna with simple and intelligent geometrical structure has been proposed for Ku/K band satellite communication systems. The radiating patch of the antenna is formed by cutting rectangular slots and extending the radiating element to some extent. The final design of the antenna with optimized parameters is fabricated on ceramic–polytetrafluoroethylene substrate materials of dielectric constant ε_r = 10.2. The antenna is excited through a microstrip feed line and has reduced ground plane that covers only the non‐radiating portion of the antenna. The reduced complexity of the antenna is easy to fabricate and has overall dimension of 40 × 35 × 1.905 mm³. The results from experimental analysis show that the proposed antenna can guarantee a wide bandwidth of 12.0 to 16.4 GHz at lower band, and the upper band covers the frequency in the range of 17.53 to 19.5 GHz. The antenna has achieved appreciable gain in the range of 3.14 to 4.68 dBi for lower band and 2.03 to 3.65 dBi for upper band. The proposed antenna has offered almost symmetrical and directional radiation pattern that is essentially suitable for serving Ku/K band satellite applications. Copyright © 2015 John Wiley & Sons, Ltd.     

宽带高增益圆极化微带天线与阵列

设计了一副宽带高增益圆极化微带天线,并进行组阵分析。天线中心频率2.6 GHz,通过增加寄生贴片和空气层来提高天线单元的增益和带宽。上下两层介质板上边长不同的切角方形贴片分别激励一个低频与高频的圆极化模,有效地拓宽了轴比带宽。仿真结果表明,反射系数|S11|<-10 dB带宽21.8%,3 dB轴比带宽12.0%,中心频率点增益9.0 dBi。对天线单元进行加工测试,与仿真结果较为吻合。设计了2×4元阵列,并进行了仿真,增益提升至17.5 dBi,3 dB轴比带宽10.4%。     

一种宽频带共形天线的特性研究

设计了一种具有宽频带特性的柱面共形天线,通过改变柱体曲率半径、长度和介电常数等参数,详细分析了其变化对共形天线性能的影响。结果表明:柱体各个参数的变化会导致天线的谐振频率、阻抗带宽以及辐射特性发生显著的改变。对设计宽频带共形天线时共形载体的选取提供了可靠依据。实际加工制作了天线,测量结果表明:该天线具有宽频带特性,可用频段覆盖2～16GHz,在工作频段内具有较好的辐射特性,增益稳定。     

Ultra wideband (UWB) dielectric resonator antenna using fractal-inspired feeding mechanism

This article examines a compact dielectric resonator antenna (DRA) for UWB applications. Here a composite feeding structure excites a dielectric resonator which in tern provides the resonant modes TE₁₁₁, TE₁₂₁, TE₂₁₂, and TE₂₂₂. The dielectric resonator (DR), built of alumina ceramic (ε_{r, DR} = 9.8), is mounted on a fractal triangular patch, inspired by Sierpinski Gasket. The suggested DRA is supported by a FR4 substrate (ε_{r, sub} = 4.4) and measures compactly 40 × 30 × 8.5 mm³. To confirm the results of its simulations, the proposed antenna's prototype is prepared and measured up to the second iteration. The measured outcome demonstrates that the suggested antenna has a frequency range of 3.38–10.71 GHz (104%) for S₁₁ < −10 dB and provides a maximum gain of 7.23 dBi at 8 GHz along with highest possible simulated efficiency of 98%. The suggested DRA is appropriate for small-range future 4G/5G UWB wireless multimedia applications due to its ultrawide bandwidth, excellent gain, reasonable efficiency, omnidirectional radiation features, and compact construction. This DRA is also suitable for repeaters of mobile and vehicular communications.     

Broadband multimode antenna and its array for wireless communication base stations

A wideband dual‐polarized antenna coupling cross resonator is proposed for LTE700/GSM850/GSM900 base stations. An additional resonance is introduced to obtain strong coupling between the dipole and resonator. Moreover, the input impedance of the proposed antenna is steadily close to 50 Ω, which results in better impedance matching. Therefore, a wide bandwidth can be achieved with multiresonance. A prototype is fabricated to verify the proposed design. The measured results show that the antenna has a fractional bandwidth of 35.7% from 690 MHz to 990 MHz for |S₁₁| < ?15 dB. Stable radiation patterns as well as gain are also obtained over the entire operating band. Moreover, a five‐element antenna array with an electrical downtilt of 0° to 14° is developed for modern base station applications. Measurement shows that a wide impedance bandwidth of 34.7% (690 MHz to 980 MHz), stable HPBW (3‐dB beamwidth) of 65 ± 5°, and high gain of 13.8 ± 0.6 dBi are achieved with electrical downtilts of 0°, 7°, and 14°.     

A simple design of planar microstrip antenna on composite material substrate for Ku/K band satellite applications

A straight forward design of rectangular slotted microstrip planar antenna fed by 50 ohm microstrip line is proposed for Ku/K band satellite applications. The radiating patch of the antenna occupies an area of 17 × 17 mm² and fabricated on 1.0 mm‐thick ceramic filled bioplastic composite material substrate whose dielectric constant (ε_r ) is 10.0. The dual resonant square‐shaped antenna has been formed by inserting four arc shape slots at the corners with the combination of circle and square and wide square shape slot at the center. The results from the measured data show that the antenna has a lower resonant mode impedance bandwidth for S11 < −10 dB is of 18.4% (11.67–14.05 GHz) and upper resonant mode bandwidth is of 8.2% (18.19–19.75 GHz) centered at 12.94 GHz and 19.04 GHz, respectively. The antenna prototype has achieved maximum gains of 3.1 dBi and 4.13 dBi with average radiation efficiencies of 75.3% and 86.4% for the lower band and the upper band, respectively. The numerical data analyses of both the measured and simulated results show relatively good agreement. Moreover, the consistent and symmetrical radiation patters of the proposed antenna make it suitable candidate for the Ku/K band satellite applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Design of 3.1–12 GHz Printed Elliptical Disc Monopole Antenna with Half Circular Modified Ground Plane for UWB Application

This paper presents a new design of an elliptical disc monopole antenna for ultra wideband (UWB) applications. The antenna is fed by a 50 Ω microstrip line and printed on a dielectric FR4 substrate of permittivity ε _r  = 4.7 and height h = 1.6 mm. The optimization on the planar elliptical disc monopole has been presented to accomplish an ultra wide 10 dB return loss bandwidth. The design includes a half-modified circular ground plane with two short I-shaped sleeves in the middle to enhance the S-parameter characteristics across the whole UWB frequency band. Furthermore, compared to a simple rectangular shaped ground plane, the proposed design enhances the bandwidth and improves input return loss. The obtained results confirm that the proposed antenna achieves greater than 90 % radiation efficiency, better than 10 dB return loss, and 0.1 ns group delay in the frequency range of 3.1–12 GHz. The parameters, which affect the performance of the antenna with respect to frequency domain and time domain characteristics, are investigated also. In addition, the proposed antenna is fabricated and the simulation results are compared to the measurement results to prove the superiority of the antenna.     

A fractal metamaterial based printed dipoles on a nickel oxide polymer palm fiber substrate for Wi-Fi applications

In this paper, a novel antenna circuit based metamaterial (MTM) structures is proposed for Wi-Fi applications. The antenna consists of two dipoles with 3 × 5 Hilbert-shaped MTM array printed with Sliver Nanoparticles Conductive Ink (SNPCI). The antenna substrate is mainly created from INP composite of: Iraqi Palm Tree Remnants (IPTR) and Nickel Oxide Nanoparticles (NONP) with Polyethylene (PE) mixture. The relative permittivity (ε_r) and permeability (μ_r) are measured using an open-stub microstrip resonator to find ε_r = 3.106 − j0.0314 and μ_r = 1.548 − j0.0907 at the frequency band of interest. Numerically, Finite Integral Technique (FIT) and Finite Element Method (FEM) of CSTMWS and HFSS formulations, respectively, are invoked to investigate the antenna performance. Experimentally, the antenna exhibits two resonances, |S₁₁| < −10 dB, at 2.45 GHz and 5.8 GHz with gain of 2.6 dBi and 4.8 dBi, respectively. The antenna shows a bandwidth of 500 MHz around the first resonance and 2 GHz at the second resonance. The measured radiation patterns at the two resonances are found to be mainly directed toward the antenna end fire with radiation efficiency of 0.8 and 0.65 at the first and second modes, respectively. Finally, the proposed antenna performance is compared against a reference antenna to reveal the excellent enhancements.     

A Compact CPW-Fed Planar Stacked Circle Patch Antenna for Wideband Applications

The article investigates the performance of planar and compact CPW-fed microstrip patch antenna that offers 10 dB impedance bandwidth over the wide frequency range between 2.59 and 7.61 GHz. The parametric analysis of various design variables is included to acquire the final design of proposed antenna. The prototype exemplary of designed antenna is experimentally tested to obtain the return loss, VSWR, radiation response and gain characteristics. The close agreement is acquired between simulated and experimental results.The projected antenna has compact size of 0.61λ₀ × 0.44λ₀ × 0.027λ₀ mm³ and offers a 10 dB wide impedance bandwidth of 5.02 GHz. Thus, it may be considered suitable for variety of wireless applications including WLAN, Wi-MAX, fixed satellite services, wireless point-to-point applications etc.