Numerical Modeling and Computer Simulation of a Meander Line Antenna for Alzheimer’s Disease Treatment, a Feasibility Study

Alzheimer’s disease (AD) is a brain disorder that eventually causes memory loss and the ability to perform simple cognitive functions;research efforts within pharmaceuticals and other medical treatments have minimal impact on the disease. Our preliminary biological studies showed that Repeated Electromagnetic Field Stimulation (REFMS) applying an EM frequency of 64 MHz and a specific absorption rate (SAR) of 0.4 - 0.9 W/kg decrease the level of amyloid-β peptides (Aβ), which is the most likely etiology of AD. This study emphasizes uniform E/H field and SAR distribution with adequate penetration depth penetration through multiple human head layers driven with low input power for safety treatments. In this work, we performed numerical modeling and computer simulations of a portable Meander Line antenna (MLA) to achieve the required EMF parameters to treat AD. The MLA device features a low cost, small size, wide bandwidth, and the ability to integrate into a portable system. This study utilized a High-Frequency Simulation System (HFSS) in the design of the MLA with the desired characteristics suited for AD treatment in humans. The team designed a 24-turn antenna with a 60 cm length and 25 cm width and achieved the required resonant frequency of 64 MHz. Here we used two numerical human head phantoms to test the antenna, the MIDA and spherical head phantom with six and seven tissue layers, respectively. The antenna was fed from a 50-Watt input source to obtain the SAR of 0.6 W/kg requirement in the center of the simulated brain tissue layer. We found that the E/H field and SAR distribution produced was not homogeneous;there were areas of high SAR values close to the antenna transmitter, also areas of low SAR value far away from the antenna. This paper details the antenna parameters, the scattering parameters response, the efficiency response, and the E and H field distribution;we presented the computer simulation results and discussed future work for a practical model.

An Inductor Model for Analyzing the Performance of Printed Meander Line Antennas in Smart Structures

Meander line antenna has been considered desirable on flight vehicles to reduce drag and minimize aerodynamic disturbance;however, the antenna design and performance analysis have made mostly by trial-and-error. An inductor model by simulating the meander line sections as electrical inductors and the interconnecting radiation elements as a quasi-monopole antenna is developed to analyze the antenna performance. Experimental verifications of the printed meander line antennas embedded in composite laminated substrates show that the inductor model is effective to design and analyze. Of the 4 antennas tested, the discrepancy of resonant frequency in simulation and experiment is within 4.6%.

Antenna-in-package system integrated with meander line antenna based on LTCC technology

We present an antenna-in-package system integrated with a meander line antenna based on low temperature co-fired ceramic(LTCC) technology. The proposed system employs a meander line patch antenna, a packaging layer, and a laminated multi-chip module(MCM) for integration of integrated circuit(IC) bare chips.A microstrip feed line is used to reduce the interaction between patch and package. To decrease electromagnetic coupling, a via hole structure is designed and analyzed. The meander line antenna achieved a bandwidth of 220 MHz with the center frequency at 2.4 GHz, a maximum gain of 2.2 d B, and a radiation efficiency about 90% over its operational frequency. The whole system, with a small size of 20.2 mm×6.1 mm×2.6 mm, can be easily realized by a standard LTCC process. This antenna-in-package system integrated with a meander line antenna was fabricated and the experimental results agreed with simulations well.

LOW PROFILE MEANDER LINE PRINTED QUADRIFILAR HELIX ANTENNA

In this paper,a new approach of meander line technique for Printed Quadrifilar Helix Antenna(PQHA) is studied.Compared with other meander line techniques,this approach has lowered the axial height of antenna greatly and improved the efficiency of model-building in simulation processing.We have focused on the analysis of radiation pattern,axial ratio,and design graph for the Meander line Printed Quadrifilar Helix Antenna(MPQHA).Finally,we have reduced successfully 67% size in geometry compared with traditional PQHA method,and obtained rather reasonable results.

Design of a Compact Monopole Antenna for UWB Applications

In this paper,a low cost,highly efficient and low profile monopole antenna for ultra-wideband(UWB)applications is presented.A new inverted triangular-shape structure possessing meander lines is designed to achieve a wideband response and high efficiency.To design the proposed structure,three steps are utilized to achieve an UWB response.The bandwidth of the proposed antenna is improved with changing meander lines parameters,miniaturization of the ground width and optimization of the feeding line.The measured and simulated frequency band ranges from 3.2 to 12 GHz,while the radiation patterns are measured at 4,5.3,6 and 8 GHz frequency bands.The overall volume of the proposed antenna is 26×25×1.6 mm^(3);whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.3 and 0.025,correspondingly.The peak gain of 4 dB is achieved with a radiation efficiency of 80 to 98%for the entire wideband.Design modelling of proposed antenna is performed in ANSYS HFSS 13 software.A decent consistency between the simulated and measured results is accomplished which shows that the proposed antenna is a potential candidate for the UWB applications.

Metamaterial-Based Compact Antenna with Defected Ground Structure for 5G and Beyond

In this paper,a unit cell of a single-negative metamaterial structure loaded with a meander line and defected ground structure(DGS)is investigated as the principle radiating element of an antenna.The unit cell antenna causes even or odd mode resonances similar to the unit cell structure depending on the orientation of the microstrip feed used to excite the unit cell.However,the orientation which gives low-frequency resonance is considered here.The unit cell antenna is then loaded with a meander line which is parallel to the split bearing side and connects the other two sides orthogonal to the split bearing side.This modified structure excites another mode of resonance at high frequency when a meander line defect is loaded on the metallic ground plane.Specific parameters of the meander line structure,the DGS shape,and the unit cell are optimized to place these two resonances at different frequencies with proper frequency intervals to enhance the bandwidth.Finally,the feed is placed in an offset position for better impedance matching without affecting the bandwidth The compact dimension of the antenna is 0.25λL×0.23λL×0.02λL,whereλL is the free space wavelength with respect to the center frequency of the impedance bandwidth.The proposed antenna is fabricated and measured.Experimental results reveal that the modified design gives monopole like radiation patterns which achieves a fractional operating bandwidth of 26.6%,from 3.26 to 4.26 GHz for|S11|<−10 dB and a pick gain of 1.26 dBi is realized.In addition,the simulated and measured crosspolarization levels are both less than−15 dB in the horizontal plane.

Wideband One Way Antenna without Grounding

This article proposes a new type of antenna which allows getting rid of certain limitations of classic monopole antenna. Like a normal monopole, this antenna belongs to a class of radio antenna consisting of a straight rod-shaped conductor. But unlike a classic monopole, this antenna can operate at all frequencies of a very wide range. In addition, it does not require grounding. The article considers the wide possibilities of antenna applications.

弯折线偶极子天线谐振特性的研究

本文研究了由矩形弯折线构成的偶极子天线的谐振特性,分析了弯折线偶极子天线的弯折次数、矩形弯折的高度以及弯折角度等参数对天线谐振特性的影响。结果表明,弯折线偶极子天线的参数改变对天线谐振特性有较强的调节作用,适当的改变天线的参数可以获得较好的天线尺寸缩减特性,适合RFID标签天线的应用。

弯折线天线原理、结构及其研究进展

弯折线技术作为一种减小天线尺寸和实现宽频带的有效手段,在现代天线设计中被广泛使用。根据不同的技术要求,研究者们提出了多种改进结构。文中介绍了6种具有代表性的弯折线天线结构,其中包括双弯折线天线、折叠式弯折线天线、立体式弯折线天线、渐变式弯折线天线、行波弯折线天线和弯折线缝隙天线。同时也对上述6种天线的工作原理以及研究进展进行了简要的阐述。

一种用于移动终端的新型内置五频芯片天线

研制了一种用于GSM850/GSM900/DCS1800/PCS1900/UMTS频段的五频内置芯片天线.芯片天线将FR-4介质（介电常数为4.4）上的曲折线和螺旋线相结合,两者分别产生谐振频段进行叠加从而实现天线宽频工作特性.弯曲的折线结构实现了天线尺寸的小型化,天线的体积为20 mm×8 mm×3.2 mm,适合用作移动手机终端的内置天线.电路板的尺寸为40 mm×93 mm,适用于新款小型手机.在驻波比小于3时,测试低频带宽为146 MHz（1030-1176 MHz）,高频工作带宽为530 MHz（1756-2286 MHz）.

一种频带展宽的小型化左手偶极子天线的设计

左手传输线加载偶极子（简称左手偶极子）可以有效实现天线的小型化，但是这种天线通常带宽窄、效率低。通过采用一种渐变的梯形网络结构代替传统的非渐变的结构形式来改善天线的阻抗特性，设计了四单元的左手偶极子天线，进而拓展了天线的带宽，天线总长度为0．2五。仿真和实物测试结果显示：天线同时工作在-1阶和-3阶谐振模式，│S11│≤-10dB的阻抗带宽达到6．5％，在工作频段内（571-610MHz），天线的增益不小于-4．25dBi，效率大于25％。

时域近场测量采样平面选择分析

利用平面波谱展开理论和时域有限差分法对几种典型天线的远场方向图建模计算 ,分析和比较了不同采样平面对远场的影响 ,以及平面波谱理论对强、弱方向性天线的适用性 ,为进一步误差分析修正奠定了基础。

偶极子RFID标签天线研究

偶极子天线是RFID标签天线中应用最广泛的一类天线结构,对半波偶极子及弯折偶极子RFID标签天线进行了分析和仿真,并比较了弯折偶极子天线的形状参数对其性能的影响。仿真结果表明,在保持天线效率的前提下,与半波偶极子相比,弯折偶极子天线具有更好的尺寸缩减特性。

非线性传输线高功率实验

设计了基于交叉耦合铁氧体非线性传输线高功率射频微波产生系统,系统由脉冲形成线、非线性传输线以及高功率匹配负载(或组合振子辐射天线)组成。由100kV高压电源和高压微波电缆构成单传输线高功率脉冲形成线,形成线输出脉冲幅度35kV,脉冲半宽60ns。高压脉冲经过非线性传输线的脉冲压缩和调制,与高功率匹配负载相连时,实验得到了峰峰值31kV、中心频率308 MHz、3dB带宽为13%的射频振荡脉冲;与组合振子天线相连时,实验得到了中心频率380MHz、3dB带宽为12%的宽谱辐射。实验结果与数值模拟基本吻合。

新型圆环嵌套多频印刷天线

提出了一种具有多频特点的新型圆环嵌套印刷天线,该天线由不同直径的圆环嵌套得到。通过电磁仿真软件CST Microwave Studio进行仿真研究,结果表明嵌套圆环的外径、宽度和嵌套数目可以对其通频带中心频率、频带宽度和通频带数目进行控制。设计出了具有2.4 GHz,3.5 GHz,5.2 GHz,5.8 GHz四个通频带的共面波导馈电的单极印刷天线和以平衡微带线馈电的对称振子天线。制作了天线实物并在微波暗室中进行测试,测试结果与仿真吻合较好,该天线具有近似独立的频率可控性和较小的尺寸,可用于WLAN和WiMAX等领域。

一款适用于第四代移动通信的宽带偶极子天线

该文设计了一款可用于第四代（4G）移动通信的宽带偶极子天线。利用寄生微带线的阻抗加载,实现不平衡-平衡转换的巴伦;设计天线臂与巴伦之间的传输线,使其在阻抗匹配的同时能延展天线臂中辐射电流径程,产生新的谐振点,实现带宽扩展。2-3 GHz频带内仿真和实测回波损耗（S11）吻合较好,小于-10 d B频带覆盖4G的6个业务频段,频带内仿真和实测方向图也显著体现了偶极子天线良好的辐射特性。

Ka频段回折线型宽带圆极化器设计

提出了一种可应用于Ka频段毫米波卫星通信系统的新型圆极化天线实现方案。利用回折线周期结构特性,只需在已有线极化喇叭天线的前方放置回折线型圆极化器,不需对已有线极化天线做任何内部修改,即可实现线极化向圆极化的转换。这种实现方式具有低成本、低设计复杂度、高灵活性的特点,可与现有的线极化毫米波天线无缝兼容。采用CST软件建立系统仿真模型,对回折线结构进行了参数分析,并对天线进行了加工与实际测试。实验结果表明:该天线的3dB以下轴比圆极化工作带宽覆盖27.5-32.5GHz。

折线振子天线的时域有限差分法分析

研究了在手机和掌上电脑等移动通信终端上应用的平面折线振子天线,用三维变换方向隐式时域有限差分法(ADI-FDTD)进行仿真。利用各向异性参数得到改进的ADI-FDTD方法,并给出计算公式便于提高计算效率和精度,对新算法的稳定性、色散关系及参数的选取进行了研究。然后用这种方法研究了平面折线振子天线的反射系数、电压驻波比和带宽等特性,得到一些有参考价值的结论。

宽带印刷偶极子天线

印刷在薄介质基片上的偶极子,其重量轻、易加工并且提供相当宽的带宽和高级化纯度,通常作为基站天线的辐射单元。介绍了一种由串联印刷偶极子对组成的宽带天线,该天线由两对偶极子组成,印刷在一个薄介质基片的正反面并通过平行带状线连通。该天线结构简单,便于印刷制作,是大型天线阵的理想辐射单元。给出了偶极子长度以及它们之间距离的变化对输入端反射系数(S11)的影响,可供工程设计参考。设计的天线其相对带宽可达62%(VSWR≤2.0),55%(VSWR≤1.5),中心频率为2.3GHz。

一种新型LTCC天线的设计

通过分析Meander-line天线技术理论及LTCC天线结构理论,并结合返折理论技术,将返折Meander-line理论技术应用于LTCC天线。最终通过理论分析与仿真优化,设计了本天线单元,尺寸为18mm×3.8mm×1.2mm的天线模块。仿真结果显示,该天线具有较好的抗阻特性、较高的隔离度、良好的交叉极化比和较为稳定的方向图和增益。