共查询到20条相似文献,搜索用时 15 毫秒
1.
利用微细加工技术, 制作出金属矩形孔阵列, 从实验和理论上研究了金属矩形孔阵在THz波段的透射极大值和极小值产生的规律.并利用透射极大值频率随矩形孔长度增大而向低频移动的特性, 在同一层金属上, 利用不同尺寸的金属孔结构形成复合金属孔阵列, 设计出中心频率可调节、频率拓宽的频率选择器件和频率拓宽器件.此研究为太赫兹滤波器等无源器件提供了新的设计思路和加工方法, 对太赫兹波技术的发展具有重要意义. 相似文献
2.
利用微细加工技术,制作出金属矩形孔阵列,从实验和理论上研究了金属矩形孔阵在THz波段的透射极大值和极小值产生的规律.并利用透射极大值频率随矩形孔长度增大而向低频移动的特性,在同一层金属上,利用不同尺寸的金属孔结构形成复合金属孔阵列,设计出中心频率可调节、频率拓宽的频率选择器件和频率拓宽器件.此研究为太赫兹滤波器等无源器件提供了新的设计思路和加工方法,对太赫兹波技术的发展具有重要意义. 相似文献
3.
《Microwave Theory and Techniques》1970,18(9):627-632
A general solution to the problem of determining first the aperture field distribution and then the transmission and reflection coefficients of an infinite planar conducting sheet perforated periodically with apertures has been formulated. The excitation is considered to be a plane wave incident at any arbitrary angle. The aperture dimensions and array element spacings were assumed to be comparable with the wavelength of the incident electromagnetic field. The solution given can include the effect of a dielectric slab used to support the thin conducting sheet. The solution is obtained by matching the tangential field components at the surface of the screen. The resulting integral equation is solved by the method of moments which reduces the integral equation to a system of linear algebraic equations that can be solved with the use of a digital computer. Accurate results for both the magnitude and phase of the aperture field distribution and the transmission coefficients for the propagating modes are determined explicitly for a specific example of slots arranged in an equilateral triangular lattice. The balance of power flow between the reflected and the transmitted waves has been checked with satisfactory results. The solution can be applied to the problem of scattering from a conducting screen with periodic apertures and to the complementary problem of scattering from a set of conducting plates by the use of Babinet's principle. 相似文献
4.
利用全矢量的三维时域有限差分法,分析了一种金属银复合结构的反常透射增强效应.该结构是在一层打有六角排列的圆孔阵列的金属银层的上方放置一层六角排列的银圆环阵列构成.与普通的单层银打孔阵列相比,该结构明显具有更高的透射峰值和更窄的透射带宽.系统分析了结构的场强分布、坡印廷矢量能流分布图、透射峰的频率色散关系,结果表明该复合结构激发的更强的独特的表面等离激元模式主导了整个透射过程. 相似文献
5.
Humberto César Chaves Fernandes Arthur Rodrigo Barros da Rocha 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(7):1171-1176
The use of photonic materials has been used in the theory of optical waves. The PBG (Photonic Band Gap) theory and material, was developed recently for optical frequencies and can be easily applied to millimeter waves, microwaves and planar antenna frequencies. The presence of photonic materials as substrate in antennas has some good characteristics such as, supression of light spontaneous emission and suppression of surface waves, allowing the application in planar antenna array. In this work an elaborate analysis using the full wave Transverse Transmission Line - TTL method, that provides efficient and concise results is applied to the planar antennas array with PBG substrate. 相似文献
6.
以基于超材料的太赫兹波透射为目的,设计并制作了四种亚波长开环共振(SRR)超材料。采用连续太赫兹波作为入射激光源,实验测量了它们在1.04 ~4.25 THz波段的功率透射属性,并采用CST Studio进行仿真,结果显示这些超材料存在一个位于2.52 THz的全局透射峰和多个局部透射峰。全局透射峰与SRR阵列的微结构和图形配置等参数有关。为了寻找一个具有较高透射效率的太赫兹感应阵列,比较了四种不同超材料微结构的归一化功率透射性能和感应差别。从这些差别中找到特定图案配置的超材料器件用于太赫兹波感应具有借鉴意义。 相似文献
7.
M. G. Evtikhov 《Journal of Communications Technology and Electronics》2010,55(8):855-862
General conditions for the existence of plane electromagnetic waves with a single nonzero electric-field component (TE waves)
in an anisotropic medium are established. A transformation that makes it possible to derive similar formulas for TM waves
(plane electromagnetic waves with a single nonzero magnetic-field component) from the formulas expressing the properties of
TE waves is considered. A general numerical algorithm is developed for calculating the amplitudes (with allowance for phases)
of the TE waves formed when an external TE wave propagates through a system of plane-parallel plates consisting of media supporting
TE waves. Formulas are obtained for the solution of the particular problem on the transmission of a TE wave through a plane
interface between two media supporting TE waves. A series of relationships that can be interpreted as generalizations of the
Snell and Fresnel relationships for media of the considered type are derived. Formulas for the transmission, reflection, and
refraction coefficients are obtained. The existence conditions for TE (TM) surface waves are derived. A numerical method is
proposed for computing the spectra of such surface waves formed on the interface between two media. For isotropic media, analytic
expressions for the spectra of surface waves are derived. It is shown that the obtained formulas are similar to the known
formulas for surface TM waves in dielectrics but, in addition, make it possible to take into account both the permittivities
and permeabilities of the media. 相似文献
8.
Chao-Chun Chen 《Antennas and Propagation, IEEE Transactions on》1970,18(5):660-665
The boundary value problem of an infinite array of thin plates arranged in a doubly periodic grid along any two coordinates is formulated in a general form for an arbitrarily polarized plane wave incident from any oblique angle. The induced current on the plate, the near-field distribution, and the distant reflected waves can be obtained to a very close accuracy. Both magnitudes and phases of the reflection coefficients for some specific examples are determined explicitly. For the case of a wave incident normally on a rectangular lattice array of narrow rectangular plates, the calculated values are in excellent agreement with the measurements in a previously published paper. 相似文献
9.
Possible determinants of pulse-wave velocity in vivo 总被引:2,自引:0,他引:2
The relationship between arterial pulse-wave velocity and the possible factors (age, gender, blood pressure, heart rate, serum lipids, and disease state) involved were examined for 127 subjects using multivariate analysis. Since a preliminary study had shown that age correlated highly with transmission time of pulse waves rather than with their velocity, the former was used in this analysis. Transmission time was obtained from the transit time between fingertip-pulse and toetip-pulse waves, as estimated from the delay of the initial rise of pulse waves and from the delay of each of the six frequency components less than 7 Hz obtained with Fourier analysis. Multiple regression analysis indicated that the possible determinants of the transmission time were age, gender, systolic and diastolic blood pressures, and phospholipid 相似文献
10.
Farman Ali Mangi Shaoqiu Xiao Qasim Ali Arain Imran Memon Ghulam Fatima Kakepoto 《Wireless Personal Communications》2018,99(2):985-997
A circular polarizer based on bi-layer split ring structure is proposed that could achieve asymmetric fission transmission of linearly polarized wave at the dual band. Firstly, a new approach of “Fission Transmission of Electromagnetic (FTEM) waves” is introduced to understand the polarization transformation behavior for linear-to-circular polarization. The designed structure achieves broadband circularly polarized wave with an asymmetric transmission over resonance frequencies by the principle of FTEM wave. The electronics circuit of proposed structure demonstrates the transformation behavior of EM waves when the electric and magnetic coupling between the upper and lower patterned SRR is reached at the certain strength. The physics of the giant circular dichroism effect and optical activity is illustrated by the surface currents distribution on the structure. The proposed structure achieves a right-handed circularly polarized wave and left hand circularly polarized wave with high transmission at 13.94–15.70 GHz and at 16.0–17.03 GHz, respectively. The axial ratio bandwidth of 11.76 and 6.86% is obtained at the dual band. The simulated and measured results exhibit good correspondence. 相似文献
11.
单层和多层有缝金属板电磁波透射的FDTD分析 总被引:5,自引:0,他引:5
采用在入射波一侧的总场边界处同时引进入射波和反射波作为激励源的FDTD方法来分析斜入射时单层和多层有缝金属板电磁波透射问题.通过计算金属板缝隙附近的散射场,提取缝隙口径面上的等效面磁流,进而得到透射截面.计算机仿真结果证实了算法的有效性.数值计算结果表明,两金属板上所开缝隙的相对偏移以及两板间插入介质板将会改变屏蔽效应.该方法可以有效分析平面波斜入射时多层金属板上任意形状缝隙的散射和透射,包括缝隙内或金属板之间填充有介质情形. 相似文献
12.
Bidirectional optical transmission using polarised light waves is demonstrated for the first time. Transmission of 100 Mbit/s signals over 13.6 km of polarisation-maintaining fibre occurs simultaneously in both directions at 1.55/?m. LD transmitters with polarisation-maintaining fibre pigtails, polarisation-maintaining fibre couplers, fibre polarisers and Ge-APD receivers are used. 相似文献
13.
钟敏 《红外与毫米波学报》2014,33(3):227-230
通过改变长方形孔的长度,利用数值模拟研究了金属-介质-金属三明治结构超材料的透射率,负折射(NRI)率和品质因数(FOM)等性质.研究结果表明,随着长方形孔的长度的增大,低频透射峰和最大透射峰都出现了红移现象.长方形孔的负折射率和负折射带宽则随着长方形孔的长度的增大而减小.这意味着可以通过调节金属-介质-金属三明治结构超材料的孔阵列的长度获得较高的透射率或者负折射率.这些结果为开发太赫兹范围的光电器件提供可能的理论. 相似文献
14.
《Microwave Theory and Techniques》1973,21(1):1-6
Transmission characteristics of a thick conducting plate perforated with either circular or rectangular holes are presented. Simple explicit formulas for predicting energy leakage through a reflector surface are derived. 相似文献
15.
传输阵包含接收阵面和再辐射阵面,各由周期排列的单元组成,两个阵面被公共接地板隔开,经由过孔销钉或槽缝相耦合。接收阵面接收发自馈源的球面波,经校正相位并传向再辐射阵面以实现前向辐射。文中提出了两种宽频带正交极化变换的传输阵单元:直接耦合角馈层叠式贴片和近轴耦合U型缝贴片,分别组成相同的接收阵面和再辐射阵面,根据宽频带阻抗匹配的要求,对这两种单元进行了优化设计。然后,采用延迟线实现相位调节,分别设计了37和21个单元的正交线极化变换传输阵,对样品整体仿真结果显示了它们的宽频带、高增益和低交叉极化电平的优良性能。 相似文献
16.
A ten-element array of log-periodic monopole antennas with a power gain of about 20 dB is described. The individual elements are designed for input continuous wave (or peak) powers of 200 kW and differ somewhat from previous monopole configurations. The array element spacing is adjusted so that when it is electronically scanned in synchronism with the associated receiving array all side and grating lobes of the two-way pattern are down at least 20 dB. Element, array, and ground screen designs are discussed, as well as the model array mutual coupling measurements, electronic scanning systems and the associated coaxial transmission lines. 相似文献
17.
通过在双层金属开圆孔阵列并嵌入对称开口谐振环结构,设计了一种新型金属-介质-金属透射增强结构.用电磁仿真软件对该结构的透射特性进行模拟,研究了单元结构的几何参数对透射峰的影响.结果表明:增加开口谐振环可以有效增加透射峰数量,实现了0.2~1.1 THz内的多频超强透射.根据透射峰处金属表面的场分布,透射峰与磁谐振、局域型表面等离子体、传播型表面等离子体、法布里-珀罗谐振及他们之间的杂化耦合有关.结果对深入研究超强透射特性及透射机理具有一定的指导意义,也为太赫兹微波器件设计和性能分析提供了重要参考. 相似文献
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19.
《Antennas and Propagation, IEEE Transactions on》2009,57(7):1931-1935