无线通讯用硅基微小Spiral天线的设计和制作

微小双波段天线通过采用微电子加工工艺在高电阻率硅片上被设计和制备,测试得到天线基本为全向辐射,增益为2.8 dB,谐振频率分别为7.6 GHz和20.2 GHz,反射系数分别为25 dB和23 dB,此天线的设计制造利于IC集成.文章还重点对天线的制作工艺进行了详细地介绍,对于以后此类研究具有一定的参考价值.     

无线电罗盘的天线信号模拟器的电路设计

根据无线电罗盘的工作原理,设计了此无线电罗盘的天线信号模拟器电路,它模拟无线电罗盘的组合天线对地面导航台无线电信号的接收功能,为无线电罗盘接收电路提供含有低频方位的高频信号;在该天线信号模拟器中,采用了单片机、GPIB等技术,重点解决了在不同频率上飞机纵轴与导航台之间的夹角可在一定的精度上的任意控制,从而实现对某型无线电罗盘的主要性能参数的自动测试任务。     

基于高频结构仿真器和神经网络的双面双频宽带偶极子天线设计

为了快速地设计一款应用于无线局域网络(WLAN)的双面结构的具有双频段、宽频带、小型化特性的偶极子天线,将偶极子贴片分别放置于介质基板的两侧,并采用微带巴伦线馈电的方式,以实现更好的宽带匹配。在偶极子的两臂分别开槽,实现小型双频特性,以满足WLAN的2.45GHz和5.49GHz的双频要求。整个天线的尺寸为28mm×44mm×1.6mm。并且利用电磁仿真软件高频结构仿真器(HFSS)和神经网络(NN)联合优化天线的尺寸,加快设计过程。仿真结果表明,当S11小于-10dB时,天线在低频和高频的带宽分别可以达到470MHz(2.29~2.76GHz)和3650MHz(4.96~8.61GHz);当S11小于-14dB时,天线在低频和高频的带宽分别可以达到210MHz(2.36~2.57GHz)和770MHz(5.13~5.9GHz)。而且该天线的方向图具有良好的全向性,实物测量与仿真结果的一致性良好,可以满足WLAN的需要。     

一种应用于微波探测的双频天线的设计

为增加火灾探测天线频带范围,基于微带贴片天线,采用凹槽加载技术,设计了中心频率在Ku(12.4～18.0 GHz)波段的双频微带单元天线.利用HFSS软件对其建模、仿真及优化,结果表明,该单元天线在14.8 GHz和16.1 GHz时回波损失达到最小值,且回波损失小于-10 dB的带宽分别为600MHz和390 MHz.利用该单元天线,进而设计了一款2×2阵列天线,实测结果表明:该阵列天线具有很好的双频谐振特性,在14.3～14.9 GHz和15.7 ～16.1 GHz频带内既保留了原单元天线好的回波损耗特性,又提高了增益,使两个频段最大增益分别达到13.7 dBi和11.3 dBi.     

基于高阶滤波的闪电电场测量与波形校正

为提高对闪电辐射电场瞬态高频分量的探测能力,抑制环境工频噪声影响,本文设计了一种基于高阶滤波的闪电电场测量系统,对于高频通带内信号,其灵敏度为12.11 V/(m/V),最小可以识别0.1 V/m的脉冲电场信号,对工频噪声的抑制可达41 dB.另一方面,为克服高阶滤波作用带来的测量电场低频失真问题,提出了一种直接根据传感器电路参数构造系统函数的波形校正方法,对失真的低频信号进行补偿.通过模拟数值和实测数据的验证分析可知,利用提出的高阶快天线测量系统以及重构方法,既可以观测得到微弱的闪电电场变化事件,又能够在一定程度上补偿波形的低频失真成分,可应用于多站闪电定位以及雷电放电参数的反演估计.     

一种小型化宽频基站天线设计

随着无线通信技术的迅速发展,为了满足2G/3G/4G频段的覆盖,同时减小天线尺寸,本文提出了一种小型化宽频基站天线.该天线由一个低频辐射单元和高频辐射单元同轴嵌套而成,±45°双极化,低频辐射单元由两对偶极子构成,通过共用偶极子臂和辐射臂弯折,来实现天线小型化。天线仿真的-15dB阻抗频带为694-960MHz(相对带宽为32%)和1695-2690MHz(相对带宽为45.5%),轴向交叉极化大于33dB,频带宽,尺寸小,增益比较高,满足2G/3G/4G通信系统的需求。     

基于CMOS工艺V-NPN晶体管设计的用于接收机的双极型有源混频器

随着声纳通信技术的发展,需要使用CMOS工艺设计用于声纳通信接收机中的低噪声低频混频器.由于MOSFETs的闪烁噪声拐角频率通常在几MHz,在低频工作时会有非常大的闪烁噪声.这使得用MOSFETs设计的传统CMOS有源混频器,在低频低噪声系统中不能使用.本文提出了使用深N阱CMOS工艺中的垂直寄生NPN晶体管(V-NPN)设计的双极型有源混频器.该垂直寄生NPN晶体管的闪烁噪声拐角频率通常为几KHz,因此可以用来设计低噪声低频混频器.本文使用0.18μm CMOS工艺中的V-NPN晶体管设计了一个双极型有源混频器.仿真结果显示,工作电压为3.3V,LO频率为50KHz,RF频率为40KHz时,该双极型有源混频器的电压增益为18.3dB,NFdsb为15.99dB,等效输出噪声,P1dB为-9.88dBm,IIP3为-1.65dBm.     

应用相关系数的小波变换图像融合算法

多聚焦图像融合的关键问题是如何保持原始图像的边缘和细节信息,由此本文提出了一种基于相关系数的小波变换图像融合策略.针对小波分解的不同频率域,设计了两种选择高频系数和低频系数的原则.选择高频系数时,采用绝对值最大、平均与选择相结合两个原则;选择低频系数时,基于平均与选择相结合、相关系数两个原则.最后将提出的算法用于多聚焦...     

一种3—3夹心复合智能机械手测距觉超声传感器

本文作者研制成一种新颖3-3夹心复合压电高频测距觉传感器.它们的谐振频率分别为430 kHz及1 MHz;带通标称Q值为10;通常内谐振接收电压灵敏度分别为—50dB及—56dB(0dB=1V/Pa·m);指向性波束开角分别为3°及1.5°.     

基于带间预测的非负支撑域受限递归逆滤波盲复原算法

针对非负支撑域受限递归逆滤波(NAS-RIF)算法对噪声敏感和耗时长等缺点,提出了一种改进的NAS-RIF盲复原算法。首先,为了改进原始NAS-RIF算法的抗噪性能和复原效果,引入了一种新的NAS-RIF算法代价函数;其次,为了提高算法的运算效率,结合Haar小波变换,仅对低频子频带的图像进行NAS-RIF算法复原,而高频子频带的信息,则通过带间预测分别从低频子频带的复原图像中预测得到;最后,为了保证高频信息的准确性,提出了一种基于最小均方误差(MMSE)的带间预测。分别对模拟退化图像和真实图像进行了仿真实验,采用该算法得到的信噪比增益分别为5.2216 dB和8.1039 dB。实验结果表明:该算法在保持图像边缘细节的前提下,能够较好地抑制噪声;此外,该算法的运算效率也得到了较大的提高。     

A triple‐band antenna for MIMO WLAN applications

A novel triple‐band antenna element by etching parasitic slot on ground plane is presented. A three‐element antenna system for WLAN MIMO communications is fabricated by using the proposed antenna element. The triple‐band antenna element is designed for the WLAN standard frequency ranges (2.4‐2.485, 5.15‐5.35, and 5.475‐5.725 GHz). The three identical antenna elements are rotationally symmetric on the substrate, isolated by using metal‐vias cavity. The measured average peak gain within the operational bandwidth is about 2.7 dBi. The isolation between the antenna elements can achieve better than 17 dB at the lower band (2.25‐2.65 GHz), while more than 32 dB at the higher bands (5.20‐5.35 and 5.47‐5.73 GHz) is obtained.     

Design of a dual‐band MIMO dielectric resonator antenna with high port isolation for WiMAX and WLAN applications

A novel dual‐band MIMO dielectric resonator antenna with high port isolation for WiMAX and WLAN applications is designed and investigated. The proposed antenna operates at 3.5 and 5.25 GHz bands. High port isolation is achieved using hybrid feeding mechanism that excites two orthogonal modes at each frequency bands. The measured impedance bandwidth of the proposed antenna covers the entire WiMAX (3.4–3.7) GHz and WLAN (5.15–5.35) GHz bands. The scalable behavior along with the frequency ratio of the antenna has also been investigated in this work. The measured isolation between antenna ports is ?52 dB at the lower band and ?46 dB at the upper band, respectively. Envelope correlation coefficient, diversity gain and mean effective gain have also been investigated. Moreover, measured results are in good agreement with the simulated ones.     

Design of a compact orthogonal fed self‐diplexing bowtie‐ring slot antenna based on substrate integrated waveguide

In this article, a novel design of compact cavity‐backed slot antenna based on substrate integrated waveguide (SIW) technology is presented for dual‐frequency communication services. A single layer printed circuit board is applied to implement the proposed antenna. The bowtie‐ring slot engraved on the SIW square cavity is excited using two orthogonal microstrip feed lines to operate at two distinct frequencies (6.62 GHz and 11.18 GHz). The proposed antenna allows each of these frequencies to be designed independently. A prototype of the proposed cavity‐backed antenna that radiates at both 6.62 GHz and 11.18 GHz is fabricated and measured. The port isolation better than 29.3 dB is achieved by utilizing the transmission zeros (TZs), which are produced due to the orthogonal feed lines, TE₁₁₀ mode and coupling between the TE₁₂₀ and TE₂₁₀ modes. The measured peak gains of the proposed diplexing antenna are 5.77 dBi and 5.81 dBi at lower and upper resonating frequencies, respectively. The proposed dual‐frequency antenna exhibits the front‐to‐back‐ratio (FTBR) and cross‐polarization level greater than 26 dB and 21 dB, respectively, at both resonating frequencies.     

A penta‐band hybrid fractal MIMO antenna for ISM applications

A miniature two‐element MIMO multiband planar patch antenna with potential applications in the ISM bands is presented. The elements of the antenna have been designed using a novel hybrid fractal geometry based on an altered Dragon Curve and the Inverted Koch. Reduced antenna dimensions are obtained with acceptable performance even at lower frequency ranges. The antenna elements are placed adjacent to each other with a very small spacing of 0.004 λ₀ (λ being the free space wavelength of 433 MHz), confining the antenna dimensions to 51 × 50 mm². The antenna resonates at the 433 MHz (ISM), 2.4 GHz (ISM), 3.9 GHZ (Fixed Satellite), 4.7 GHz (UWB) and 5.8 GHz (ISM) frequency bands. The antenna exhibits |S₁₁| ≤ ?10 dB, |S₂₁| ≤ ?16 dB, an ECC ≤ 0.01 for all operating frequencies, with circular polarisation at the 2.4 GHz and 5.8 GHz bands and linear polarisation at the others. The simulated structure was fabricated and tested, with the simulated and measured results displaying acceptable agreement.     

A 60‐GHz on‐chip slot‐array antenna in integrated‐passive‐device technology for antenna‐in‐package applications

A new millimeter‐wave antenna structure on a low‐cost, production platform integrated passive device technology is presented. The antenna consists of a 2‐by‐1 array of slot antennas at 60 GHz. An in‐house developed on‐chip antenna measurement setup was used to characterize the fabricated antenna. The measurement results show an antenna gain of more than 5 dBi with a return loss of 18 dB at 60 GHz. The better‐than‐10‐dB impedance bandwidth of the antenna covers the 60‐GHz unlicensed band from 57 to 64 GHz. The 3‐dB beamwidths of the antenna are 105° and 76° at E‐plane and H‐plane at 60 GHz, respectively. The size of the die of the antenna is 2 mm × 4.5 mm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:155–160, 2014.     

Compact microstrip antennas with very wide ARBW and triple circularly polarized bands

This article presents two compact circularly polarized microstrip antennas with a very wide 3 dB axial ratio bandwidth and triple circularly polarized bands. A hexagonal stub (circular polarization element) along with tuning element in the ground plane is used for achieving wide 3 dB ARBW in antenna‐1, while a novel approach of using a parasitic strip around the circular polarization element is used in antenna‐2 for introducing band elimination notches in the circularly polarized band of antenna‐1. The antenna‐1 has a ?10 dB impedance bandwidth of 12.34% (3.8‐4.3 GHz), 84.02% (4.9‐12 GHz), and 3 dB ARBW of 79.94% (4.9‐10.9 GHz). The antenna‐2 displays circularly polarized band elimination notch characteristics with ?10 dB impedance bandwidth of 24.80% (3.85‐4.94 GHz), 31.72% (6.1‐8.4 GHz), 25.35% (9.3‐12 GHz), and 3 dB ARBW of 4.84% (4.63‐4.86 GHz), 19.08% (6.02‐7.29 GHz), and 5.7% (9.54‐10.1 GHz). Both the antennas are designed and fabricated on FR4 substrate of dimension (0.52 × 0.52 × 0.04)λ₀ at a frequency of 7.9 GHz.     

A compact multi‐band multi‐input multi‐output antenna for 4G/5G and IoT devices using theory of characteristic modes

A compact four element multi‐band multi‐input multi‐output (MIMO) antenna system for 4G/5G and IoT applications is presented in this paper. The proposed antenna is developed using the theory of characteristic modes helping in systematic design of MIMO antenna system. It consists of four L‐shaped planar inverted‐F antenna (PIFA) elements each operating at 3.5, 12.5, and 17 GHz bands with the bandwidth of 359 MHz, 1 GHz, and more than 3.7 GHz, respectively. The proposed antenna system is suitable for both 4G/5G and internet of things devices as it shows the satisfactory MIMO system performance. Good isolation characteristics are observed by implementing complimentary Metamaterial structure on the ground plane resulting in isolation level lower than ?21 dB between the antenna elements. The proposed antenna is fabricated and experimental results are also presented and discussed.     

Enhancement of gain with corrugated Y‐shaped patch antenna for triple‐band applications

In this article, investigation has been carried out on Y‐shaped patch antenna to produce triple‐band for wireless applications. The corrugated Y‐shaped patch antenna is considered to produce low reflection coefficient with high gain at the triple‐bands. The corrugated Y‐shaped patch antenna is resonates at 4.19 GHz (4‐4.43 GHz), 8.79 GHz (8.61‐9.01 GHz), 13 GHz (12.6‐13.6 GHz) frequencies with reflection coefficient of ?29.26 dB, ?34.87 dB, ?40.37 dB and gain 5.01 dBi, 5.42 dBi, 7.46 dBi, respectively. The proposed corrugated Y‐shaped patch antenna works three frequency bands at radio communications, satellite communications, and aeronautical radio navigation applications, respectively.     

Design of a printed log‐periodic dipole array antenna with high gain for millimeter‐wave applications

In this article, a V‐band printed log‐periodic dipole array (PLPDA) antenna with high gain is proposed. The antenna prototype is designed, simulated, fabricated, and tested. Simulation results show that this antenna can operate from 42 to 82 GHz with a fractional impedance bandwidth of 64.5% covering the whole V‐band (50–75 GHz). The antenna has a measured impedance matching bandwidth that starts from 42 to beyond 65 GHz with good agreement between the experimental and simulated results. At 50 and 65 GHz, the antenna has a measured gain of 10.45 and 10.28 dBi, respectively, with a gain variation of 2.6 dBi across the measured frequency range. The antenna prototype exhibits also stable radiation patterns over the operating band. It achieves side‐lobe suppression better than 17.26 dB in the H‐plane and better than 8.95 dB in the E‐plane, respectively. In addition, the cross‐polarization component is 18.5 dB lower than the copolarization with front‐to‐back ratio lower than 24.1 dB in both E‐ and H‐planes across the desired frequency range. Based on a comparison of performance among the reported work in the literature, we can say that the proposed PLPDA antenna is a proper candidate to be used in many applications at V‐band frequency. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:185–193, 2015.