基于高阻抗表面的螺旋天线设计

利用高阻抗表面的同相反射特性,将其加载到阿基米德螺旋天线背腔的边缘区域,从而改善了天线增益,实现低剖面设计。仿真结果显示,与传统背腔式螺旋天线相比,增益稳定性显著提高。在3¹2 GHz的工作频段内,驻波比小于2,阻抗匹配良好,辐射方向图保持稳定。在约7.8 GHz的频带宽度内轴比小于3 dB,实现了较好的圆极化性能。     

一种新型末端加载的宽带平面螺旋天线设计

平面阿基米德螺旋天线是一种应用广泛的典型宽带天线,具有低轴比、宽频带等优良特性。针对其低频特性较差的特点,设计制作了一种末端加载电阻的新型平面阿基米德螺旋天线。该天线采用同轴巴伦馈电,加装反射背腔,从而达到小型化的目的。经过测量,天线在低频范围内具有良好的驻波比和轴比特性,在整个频带内具有较好的增益,起到了扩展低频频带的作用,能够满足工程使用的要求。     

变螺距法向模螺旋通信天线

螺旋天线按其辐射模式可分为轴向模和法向模辐射两种.轴向模螺旋天线是一种园极化、宽频带行波天线.它要求单圈螺旋的周长约为一个波长.这种天线最大辐射方向沿螺旋的轴向.法向模螺旋天线要求螺旋的尺寸大大小于工作波长,这是一种线极化驻波天线、最大辐射方向在垂直于螺旋轴的平面上.这种天线在“谐振”时可以大大缩短天线的几何尺寸,它与同长度的鞭天线相比辐射电阻大62%.目前开始在移动通信中应用. 集总参数加载天线虽然可以改变局部处的电流分布,但是由于它的机械性能差,不适宜在移动车体上采     

带异形反射腔和寄生螺旋的均匀升角轴向模螺旋天线

为了改善轴向模螺旋天线的辐射特性,在带有寄生螺旋的均匀升角轴向模螺旋天线基础上,设计了一种带有曲反射面背腔的螺旋天线,并用HFSS软件对天线的辐射特性进行了仿真分析。通过对比几种不同形式的螺旋天线的仿真结果,证明了该种螺旋天线可以有效地提高轴向模螺旋天线增益系数,圆极化一致性良好,是一种提高轴向模螺旋天线性能的有效方法。     

一种新颖的光子带隙平面螺旋天线

介绍了阿基米德螺旋天线的原理与设计方法,仿真了背腔式阿基米德螺旋天线,并与实际测试结果吻合;研究了一种新颖的光子带隙平面螺旋天线,这种天线用光子带隙代替金属反射腔作为反射面以得到单向波束,仿真与实验发现,光子带隙阿基米德螺旋天线的增益提高约有2dB,后瓣降低了10dB,在有效的工作带宽内天线的性能得到了改善.     

宽频带卫星导航平面螺旋天线设计

提出了一种覆盖GPS、格洛纳斯和北斗3种全球卫星导航系统频点的一种天线,利用阿基米德平面螺旋天线的宽带特性实现了1.2².6GHz的频带全覆盖。天线通过改进巴伦降低了剖面,使用金属背腔获得了定向辐射,并在背腔上开槽优化了驻波和轴比。按照设计尺寸对天线进行加工,测试结果表明天线性能较好,在全频段内增益大于3dBi,驻波小于1.8,轴比小于4dB。     

加载介质透镜的超宽带平面螺旋天线设计

针对乳腺癌检测、成像等医疗领域对天线高增益及宽频带的需求,研究设计了一款加载介质透镜的超宽带平面螺旋天线。该天线采用双臂平面阿基米德螺旋天线作为辐射单元,在辐射臂外围间隔一定距离处加载金属圆环以改善驻波性能,并由指数渐变式微带巴伦作为馈电结构。天线顶部加载介质透镜,底部设置金属圆台形反射背板,实现了调整波束形状和提高天线增益的目的。加装圆柱形天线罩后天线高度约为87.53 mm,直径约为46.50 mm。仿真结果显示,天线在3－12 GHz 工作频带内回波损耗小于-10 dB,辐射方向图呈现良好的定向辐射特性,实测结果与仿真结果基本一致。     

探地雷达超宽带背腔蝶形天线设计与实现

设计实现了一种中心频率为400 MHz的吸波材料填充式背腔蝶形天线,并将此天线应用于超宽带探地雷达系统,组装完成了一套400 MHz无线控制探地雷达系统样机。背腔式设计的探地雷达收发天线可以克服传统蝶形天线在H面全向辐射所带来的缺点,从而提高雷达系统的信噪比及收发天线之间的隔离度。对背腔蝶形天线的设计进行了规律性研究,总结了吸波材料填充式背腔蝶形天线系统在工程化实现时的设计经验。实际路测数据验证了所设计背腔天线在此套探地雷达系统中性能表现稳定良好。     

EBG结构在阿基米德天线中的应用

提出了一种基于EBG结构的天线系统截面优化方案，采用EBG结构代替以往常用的λ/4反射腔结构，可以使天线系统截面高度大大缩减。并对背面加载EBG结构的阿基米德螺旋天线辐射特性进行了仿真分析，仿真结果表明EBG结构可以代替反射腔结构使天线具有单向辐射特性。     

应用于Wi-Fi频段的背腔式缝隙天线设计

采用波导反射模型分析了背腔深度对缝隙天线辐射特性的影响, 通过仿真计算, 确定了当背腔深度等于四分之一波导波长时, 金属背腔会使缝隙天线的输入电阻加倍, 但对输入电抗产生影响较小, 根据以上仿真结果, 提出了一种有效的背腔式缝隙天线的输入阻抗电路模型, 分析了馈电位置和缝隙长度对天线谐振点的影响, 为缝隙天线的多频点设计提供了理论依据.结合仿真工具, 设计了两类工作于Wi-Fi频段的背腔式缝隙天线:第一类天线工作于室外2.4 GHz频段; 第二类天线可以同时工作于2.4 GHz和5.2 GHz频段.最后, 对天线的S₁₁系数进行了实测, 实测与仿真结果基本一致.     

Finite-volume time-domain analysis of a cavity-backed Archimedean spiral antenna

This paper presents a comprehensive analysis of a broadband (2-18 GHz) cavity-backed Archimedean spiral antenna. The simulation of the device is performed using the finite-volume time-domain method. The high geometrical flexibility of this method permits a detailed modeling of the antenna including the thin substrate, the feeding balun, and the cavity loaded with a honeycomb absorber. The simulated far-field radiation patterns and the return loss are compared to measurements, showing an excellent agreement over the whole frequency band. The radiation mechanism of the spiral is visualized by observing the current distribution on the spiral arms for both pulsed and harmonic excitation modes.     

Size reduction of cavity-backed slot antennas

A technique for reducing the dimensions of the cavity of a cavity-backed slot antenna (CBSA) is presented, which facilitates proper fabrication and integration of miniaturized slot antennas on multilayer substrates. This is accomplished by replacing the solid metal around the traditional slot antennas with a specific metallic pattern that can be viewed as a series of parallel strip lines placed around the slot antenna. This metallic pattern is then modified by designing the parallel strips in a compact fashion to reduce the overall antenna dimensions and obtain a reduced-size CBSA. It is shown that, for a simple straight slot antenna, the overall occupied volume of the modified cavity backing the slot antenna can be reduced by more than 65% without affecting the high radiation efficiency of the antenna. A number of traditional cavity backed slot antennas and the proposed modified CBSAs are designed, fabricated, and measured. The reduced-size CBSAs show a very low input VSWR, low cross-polarized radiation levels, and high radiation efficiency. Despite their small ground plane size, the proposed cavity backed slot antennas have front-to-back ratio (FTBR) values in the range of 6-7 dB.     

Design and Analysis of a 3-Arm Spiral Antenna

A novel 3-arm spiral antenna structure is presented in this paper. This antenna similar to traditional two-arm or four-arm spiral antennas exhibits wideband radiation characteristic and circular polarization. Advantages offered by the new design are two fold. Unlike the traditional spiral antennas the three-arm spiral can be fed by an unbalanced transmission line, such as a coaxial line or coplanar waveguide, and therefore an external balun is not needed at the feed point. Also by proper choice of arms' dimensions the antenna can be directly matched to any practical transmission line characteristic impedance and therefore external matching networks are not required. This is accomplished by feeding the antenna at the outer radius by a coplanar waveguide (CPW) transmission line and tapering it towards the center. The antenna can also be fed from the center using a coaxial or CPW line perpendicular to the plane of the spiral antenna. A full-wave numerical simulation tool is used to optimize the geometry of the proposed 3-arm spiral to achieve a compact size, wide bandwidth operation, and low axial ratio. The antenna is also designed over a ground plane to achieve a unidirectional radiation and center loading is examined that improves the axial ratio. Simulated results like return loss, radiation pattern, gain, and axial ratio are compared with those obtained from measurements and good agreements are shown. Because of its unique feed structure and compact size, application of the proposed 3-arm spiral antenna for wideband array applications is demonstrated     

SIW 耦合馈电阵列天线

提出一种新型宽带、结构紧凑的基片集成波导(SIW)背腔阵列天线的设计方法。所设计的SIW 阵列由紧密相连的背腔构成馈电网络,每个背腔上开宽缝作为辐射单元。SIW 背腔天线单元紧密排列,主要通过单元间感性耦合窗耦合馈电。SIW 背腔既是辐射单元又能实现能量分配,不需加载额外的馈电网络,因此该阵列结构十分紧凑。工作在20 GHz 频段的2×2 SIW 耦合馈电阵和4×4 SIW 耦合馈电阵已加工实现,仿真和测试结果表明所提出的SIW阵列设计方法简单、阵列结构紧凑、天线辐射性能良好。另外,本文研究了高增益大规模阵列天线的组阵方法。在2×2 SIW 耦合馈电阵的基础上,采用8×8 SIW 并联馈电网络加载天线子阵的方法设计了16×16 宽带高增益SIW 阵列天线并进行了加工测试。结果表明,采用这种组阵方法,天线阵阵元排布紧密,天线具有带宽宽、增益高、损耗低等优点。     

密距八木天线的设计与仿真

介绍了应用密距原理设计的密距八木天线,采用T形匹配天线来代替传统的用于激励器的折合振子和用于反射器及引向器的半波偶极子,通过减小T形匹配天线之间的距离来实现天线的小型化设计。以中心频率为500 MHz密距八木天线为例,说明了天线的设计过程,设计结果表明,该天线具有较为理想的技术指标,同时,相对于传统的八木天线,该设计使天线尺寸明显减小。     

小型化八边形基片集成波导背腔缝隙天线

提出一款新颖的W波段八边形基片集成波导(SIW)背腔缝隙天线。相较传统的缝隙天线，具有体积小、易加工、Q值高、成本低等优点，且易于成阵。通过调节天线背腔缝隙的长度、宽度，以及SIW腔体的尺寸优化天线的辐射特性，通过电磁仿真软件HFSS对模型进行仿真优化，确定了天线的最优结构。仿真实验结果表明，所设计的天线相对带宽约4.5%，方向性优良，中心频率点谐振深度<-31 dB，天线最大增益达到5 dBi，满足设计要求，验证了设计的正确性。所设计的SIW背腔缝隙天线拓宽了数字通信的可用频谱，是一种新的尝试，可为以后的研究提供新的参考思路。     

Design of a broadband planar cavity-backed circular patch antenna

This paper presents a design of a low-profile cavity-backed circular patch antenna for broadband applications. By using substrate integrated waveguide (SIW) based cavity and feeding mechanism, a planar cavity-backed patch antenna is realized. The proposed study demonstrates that a wide impedance bandwidth can be achieved by employing a rectangular SIW-based cavity underneath the conventional circular patch. Additionally, to generate circular polarization (CP), the patch has been reduced diagonally and shorted by a via-probe. Finally, a CP SIW-based antenna is designed and operating for a wide impedance bandwidth of 23.10% below −10 dB criteria, ranging from 9.09 GHz to 11.40 GHz and axial-ratio (AR) bandwidth of 270 MHz (10.30–10.57 GHz). The proposed design is fabricated by means of a printed circuit board (PCB) procedure. The simulated results are validated with the experimental one which agrees well with each other in the terms of S₁₁, antenna gain, AR and radiation patterns. Moreover, the proposed design exhibits unidirectional radiation characteristics with the measured peak gain of 6.6 dBic while maintaining planar integration.     

Slot spiral antenna

When compared to printed cavity-backed spirals, slot spiral antennas offer the possibility of designs that are conformal and very thin. We discuss the physical characteristics of a cavity-backed slot spiral, as well as the associated infinite balun and termination designs. Simulations of the proposed cavity-backed spiral are presented and used to optimize the antenna's various parameters. Comparisons of measurements and calculations are also given, to validate the gain and axial-ratio computations. Several options for miniaturizing this design, using capacitive and inductive loadings, are also presented