Radiation from Electromagnetic Bandgap Microstrip Structures

The radiation from electromagnetic bandgap (EBG) microstrip structures is studied. The results show that the radiation from an EBG microstrip structure at most of the frequencies in the stopband and the passband is larger than that of the corresponding conventional microstrip line. Therefore, EBG microstrip circuit s should be shielded and new EBG microstrip structures whose radiation is little should be developed.     

Closed-Form Expressions for the Electromagnetic Radiation of Microstrip Signal Traces

An analytical study of the unintentional electromagnetic radiation of a microstrip signal trace is presented. Based on transmission-line theory and appropriate far-field Green's functions, a closed-form solution for the electric field is developed, including the contribution from the vertical terminal connections. It allows calculating the frequency and directional response of the radiated emission, depending on the material and geometrical parameters and terminal load impedances. For the special case of matched termination, the general solution assumes a compact form, allowing to set up a formula for the peak-amplitude frequencies. It is shown that in the higher frequency region, where the wavelength is comparable or shorter than the line length, the frequency-response envelope continuously rises with 20 dB/dec. Based on appropriate simplifications, the asymptotic solution for the electrically short line is deduced, including a practical formula for the maximum electric field. It is found that the usual small-current-loop (magnetic-dipole) estimation is incomplete due to the omission of the electric-dipole contribution.     

Radiation from Microstrip Discontinuities

Radically different methods of calculation by Lewin and by van der Pauw are compared. It is shown that the difference in the two sets of results is due not to the difference in method, but to assumptions on the value of dielectric constant to be used when calculating the substrate polarization. Curves show that differences of up to 30 percent can arise from this source, but the differences are much smaller for the larger values of dielectric constant.     

大功率YAG固体连续激光器电源的电磁辐射对环境的影响

对国产５００瓦ＹＡＧ连续固体激光器电源的电磁辐射进行了频谱分析和综合场强测试,频谱分析结果表明,其电磁辐射频率范围为０～４００ＭＨｚ．由于人体共振频率通常在３０～３００ＭＨｚ之间,当人体处于共振频率的电磁场照射时,机体平均单位重量所吸收的功率即比吸收率（ＳＡＲ）最高。用综合场强仪对激光器电源周围的电磁辐射进行的测试表明,综合场强值随着激光功率的增加而增大,当激光输出功率达到５２０Ｗ时,激光器电源周围最大场强值超出国家标准规定值的２倍以上。根据测试结果,对固体激光器电源电磁辐射防护提出了建议。     

AIM Analysis of Scattering and Radiation by Arbitrary Surface-Wire Configurations

The adaptive integral method is utilized to solve electromagnetic scattering and radiation problems of conducting surface-wire configurations. The method of moments (MoM) is applied to establish the integral equations where triangular type basis functions are used to represent the currents on surfaces and wires. Attachment mode has been used to model the surface-wire junction to ensure the current continuity. The resultant matrix system is then solved by an iterative solver where the adaptive integral method (AIM) is employed to reduce memory requirements and to accelerate the matrix-vector multiplications. Numerical results are presented to demonstrate the accuracy and efficiency of the present technique for the arbitrary surface-wire configurations     

Electromagnetic THz Radiation Modeling by DPSM

THz or T-ray imaging and spectroscopy are becoming increasingly popular nondestructive evaluation techniques for damage detection and characterization of materials. In order to understand the interaction between the T-ray electromagnetic waves and dielectric media a reliable model of electromagnetic wave propagation through dielectric materials must be developed. A recently developed semi-analytical method called the distributed point source method (DPSM) is extended to model electromagnetic wave propagation in THz range. Since T-ray signals generated by emitters or sources are close to Gaussian beams, the DPSM modeling is carried out for Gaussian beams generated by finite sized emitters. The DPSM generated results are compared with the analytical and experimental results. T-ray propagation in layered structures in absence of any anomaly and the interaction between the Gaussian beam and the spherical scatterer are also investigated.     

基于温度图像检测的微带线电磁波能量损耗分析

功率放大器输出功率在传输过程中的损耗是电路设计的重要参数.为了提高功率损耗,以及引起的温度特性的测量精度,详细分析了微带线的特性阻抗和传输特性,在此基础上提出一种新的测量方法.该方法采用了温度图像对三种不同宽度的微带线的电磁能量损耗和温度的测量.实验结果表明,这种方法为射频与微波电路的功率损耗和温度测量提供方便,同时为...     

On the Radiation from Microstrip Discontinuities

The method of an earlier paper by Lewin is used to calculate, more accurately, the radiated power from a microstrip termination. The substrate dielectric constant epsilon is used instead of the effective dielectric constant epsilon/sub e/ in the polarization term. The open-circuit, short-circuit, and matched coaxial terminations are deduced as particular cases of the general termination. On comparison with Lewin's results, differences of up to 30 percent have been found, but the differences are much smaller for the larger values of the actual relative dielectric constant epsilon. Curves show that the short-circuit termination radiates less than a quarter that of the open circuit, and can be considered as a means of reducing losses in microstip resonators. The parallel post configuration is also considered.     

微带功率均衡器的设计

微波功率管的输出功率在工作频带内存在一定的起伏,导致下一级功率管欠激励或过激励工作,加入级间功率均衡器设计,改善功率组件平坦度和稳定性。根据原理,设计吸收式微带功率均衡器,利用微波仿真软件Microwave Office构建电路模型,进行仿真设计,软件优化的具体步骤,注意事项,总结设计经验,最后设计出实物,得到所需均衡曲线。     

An Electromagnetic Time-Harmonic Analysis of Shielded Microstrip Circuits

A Galerkin analysis of microstrip circuits of arbitrary planar geometry enclosed in a rectangular conducting box is described. The technique entails a time-harmonic electromagnetic analysis evaluating all fields and surface currents. This analysis is suitable for the accurate verification of microstrip designs prior to fabrication. A computer program implementing the analysis has been written in Pascal on a personal computer. Agreement with measurements of several microstrip structures suggests a high degree of accuracy.     

新型电磁晶体微带天线设计

提出了一种新型的双面电磁带隙微带结构,并运用有限元法对其进行了仿真分析,计算结果显示该结构具有紧凑超宽阻带和低通特性良好的特点.在此基础上,设计了一种基于该结构的新型电磁晶体微带天线.计算和实验表明,与普通贴片天线相比,新型电磁晶体天线不仅抑制了2～6次谐波,在比较宽的频带内有效地抑制了高次谐波引起的辐射,而且克服了传统电磁晶体微带天线的一些缺陷,因而完全可以取代传统形式的电磁晶体天线.由于新型电磁晶体微带天线可以明显改善有源天线系统的性能,必将在现代有源通信领域得到广泛的应用.     

高功率干扰设备电磁辐射危害性及防护分析

电磁辐射危害人体健康,如不采取必要防护措施,长期接触会造成不可恢复的严重伤害。强功率干扰是电磁作战的必要手段,接触干扰设备的作战人员不可避免地会受到电磁辐射影响。针对电磁辐射的危害,对人体受害机理、典型防护措施和安全限界标准进行了简要介绍,在分析电磁波辐射场传播特性的基础上,对L频段高功率有源相控阵干扰设备的电磁辐射场强进行计算,明确了安全工作条件,提出了具体的安全防护措施。     

微带功分器的设计

介绍了宽带微带功分器的设计方法,设计工作频带在6～18GHz的微带功分器,使用Agilent公司的高级设计系统（ADS）软件进行仿真,得到了理想的结果。     

电力线载波通信电磁辐射和OFDM调制技术的研究

介绍了PLC电磁辐射产生的原因、影响因素和抑制措施,电磁辐射可通过OFDM调制技术灵活的选择载波频率得到抑制。对OFDM调制技术的原理进行分析,建立数学模型,并介绍了OFDM技术的应用优势。     

Spurious Radiation from a Microstrip Y Junction

The radiation from a microstrip Y junction is calculatcd as a function of angle. It is shown that the radiated power increases monotonically with the Y angle, decreases inversely as the dielectric constant of the substrate for large permittivities, and increases as the square of the substrate thickness for thin substrates.     

Microstrip Patch Antennas on Tunable Electromagnetic Band-Gap Substrates

A tunable metamaterial in integrated circuit structures is investigated through an example of a microstrip patch antenna on a mushroom-type electromagnetic band-gap (EBG) structure. The patch antenna is designed as a half-wavelength resonator of an EBG loaded microstrip transmission line. The operating frequency of a patch antenna can be switched and controlled dynamically by loading diode switches in between vias and the ground plane. When the switches are on, the EBG surface is short to the ground and is at its on-state; while when the switches are turned off, the EBG surface is dc open and is at its off-state. It is found that the resulting patch antenna in-band resonant frequencies are very different at these two states. Antenna dual-band frequencies, gain, efficiency, and radiation patterns are characterized. The designed switchable EBG-patch antenna is fabricated and tested in these two states. The measurement is found in good agreement with simulation. An example is also given for the case of selected switches within the EBG elements to tune dynamically the resonant frequency.      

蘑菇型EBG微带天线电磁辐射特性分析

利用矩量法对探针馈电的蘑菇型EBG微带天线的电磁辐射特性进行了分析。首先建立了天线模型,采用细导线的带模型将馈电探针和EBG短路过孔等效为细带,并与EBG金属表面和微带贴片一样均采用平面三角面元剖分,RWG基函数作为电流展开函数,将线面连接问题转化为面面连接问题。然后给出了采用空域矩量法对天线辐射特性进行分析的全过程,并介绍了激励源的添加模型。最后对蘑菇型EBG微带天线的回路损耗、输入阻抗和方向图等特性进行了分析计算,相关结果与FEKO和文献吻合良好,验证了本文方法的正确性。     

Radiation Conductance of Open-Circuit Microstrip (Correspondence)

The radiation conductance of an open-circuit microstrip stub is determined. The losses due to radiation from a stub are shown to be a significant fraction of the total loss.     

浅谈移动通信中电磁辐射的影响

该文主要阐述了移动通信中电磁辐射的主要来源,并对移动通信中电磁辐射的影响做了初步的分析。