矩形波导斜切口面辐射特性的FDTD分析

应用时域有限差分(FDTD)法,结合时域近场 远场转换公式,分析矩形波导斜切口面的辐射特性.分析的斜切口面是把矩形波导管两个窄边同时渐削,宽边尺寸保持不变形成的辐射口面.应用FDTD法分析,较精确地解决了波导边缘的绕射问题.计算了主模激励时主面辐射方向图,与实验结果基本吻合.本文为这种波导斜切口面天线的分析设计提供了一种较精确、方便有效的方法.     

Radiation from a Rectangular Waveguide Filled with Ferrite

This paper presents an approximate analytical solution to the problem of radiation from a ferrite-filled rectangular waveguide. The field distribution at the mouth of the guide is assumed to be unaffected by the termination of the guide. The vector Huygens' principle is applied to find the far-zone radiation field from the determined aperture field. The solution to the problem is found in this manner for the cases of longitudinal and transverse magnetization of the ferrite. The transverse magnetization case is supplemented with a discussion of a specfic numerical example which includes plots of the aperture field distribution and the phase angle as well as plots of the far-zone radiation field. The experimentally known phenomenon of the effect of the applied magnetic field upon the shift of the main lobe is demonstrated and verified analytically.     

矩形波导纵向缝隙的矩量法分析

该文提供了对矩形波导纵向缝隙求解的更为精确的矩量法分析,同时考虑了缝隙电场的横向分布特性和波导壁厚的影响。对缝隙的谐振长度进行了实例计算,对比实际测量和软件仿真结果,具有很高的精确度。随后对算法的收敛性进行了分析,发现该文算法在基函数取到20,模式数取到2020时基本收敛。该文还对缝隙电场横向分布特性在计算缝隙谐振长度时的影响进行了分析,结果表明其在半高波导、大缝隙偏置、大缝隙宽度和窄壁厚这几种情况下影响比较大。     

Analysis and closed-form solutions of circular and rectangularapertures in the transverse plane of a circular waveguide

An analysis is carried out to determine the discontinuity susceptance of a circular or rectangular aperture in the transverse plane of a circular waveguide. Closed-form solutions based on the scattered amplitude calculations and aperture coupling theory are derived. Example solutions for a small circular aperture and a resonant rectangular aperture are given. The calculated results agree very well with the experiments. The results have many applications in the design of circular waveguide components and circular waveguide-backed aperture antennas     

Rectangular Waveguides with Impedance Walls

The propagation of guided waves in a rectangular geometry having impedance boundary conditions is investigated. An impedance compatibility relation is derived that must be satisfied in order that a separable modal solution exists for a given impedance configuration. Several new rectangular waveguides are developed; among them are 1) a tall rectangular waveguide operating in a dominant H/sub 10/ mode with no H/sub 0N/ modes; 2) a rectangular waveguide with two parallel anisotropic impedance surfaces; 3) a rectangular waveguide with two parallel walls having isotropic impedance surfaces, the other two walls being anisotropic; 4) a rectangular waveguide supporting only E modes; and 5) rectangular coaxial systems containing impedance surfaces. The modal structure of rectangular waveguides with impedance boundary conditions offers advantages over the conventional waveguide. The potential of oversizing for low-loss and high-power applications is enhanced because of the additional modal control provided by the impedance surfaces. Other applications are suggested.     

大功率矩形软波导的研制

矩形软波导是微波设备和馈线之间连接必不可少的一种器件。为此，我们提出了一种矩形软波导的研制方法，并在理论上进行了较为详细的分析、计算。所制得的波导具有低损耗、小驻波、大功率的特点。此研制方法可作为所有矩形软波导的通用设计。     

Approximate pattern calculation of a leaky waveguide

A method is described for calculating the patterns of leaky waveguides radiated from the aperture in the metal wall of a waveguide with a rectangular cross section, the waveguide and the aperture being assumed of infinite length along the axis, the tangential components of the electric field on the aperture being assumed to have been prescribed. This method is accomplished by substituting a well approved elliptic cylinder for a boundary with a rectangular cross section. Measurements have been made for the leakyHguide to verify the accuracy of this method.     

Microwave Magneto-Optic Bragg Modulators with Rectangular MSFVW Pulses

Microwave magneto-optic （MO） modulators can directly transform radio frequency （RF） signals into optical data through the Bragg diffraction of guided optical waves （GOWs） induced by microwave magneto-static waves （MSWs）. According to the MO coupled-mode theory, the modulation of continuous GOWs by a rectangular magneto-static-forwardvolume-wave （MSFVW） pulse in MO film waveguide is studied in the small signal case and the modulated optical pulse at the output is analyzed by means of an analytical form, which is dependent on the instantaneous diffraction intensity determined by the overlap of rectangular MSFVW pulse and light beam aperture. On the basis of it, the characteristics of MSFVW-based MO modulators can be explained well for the case of rectangular pulse modulation. It is also shown that the line codes of optical data generated by MO Bragg modulators can be controlled by adjusting the duty factor of modulating pulse signals.     

Microwave Magneto-Optic Bragg Modulators with Rectangular MSFVW Pulses

Microwave magneto-optic (MO) modulators can directly transform radio frequency (RF) signals into optical data through the Bragg diffraction of guided optical waves (GOWs) induced by microwave magneto-static waves (MSWs). According to the MO coupled-mode theory, the modulation of continuous GOWs by a rectangular magneto-static-forwardvolume-wave (MSFVW) pulse in MO film waveguide is studied in the small signal case and the modulated optical pulse at the output is analyzed by means of an analytical form, which is dependent on the instantaneous diffraction intensity determined by the overlap of rectangular MSFVW pulse and light beam aperture. On the basis of it, the characteristics of MSFVW-based MO modulators can be explained well for the case of rectangular pulse modulation. It is also shown that the line codes of optical data generated by MO Bragg modulators can be controlled by adjusting the duty factor of modulating pulse signals.     

矩形波导加载介质块的谐振模型

本文利用输入阻抗的变分公式导出了矩形波导中对称加载介质块的等效滤波器模型，从而利用其网络揭示了其中的波型转换和谐振原理，利用本文模型的计算结果同文献［１］、完全吻合。本文方法对于这种滤波器的工程设计具有实际意义。     

Analysis of Small Aperture Coupling Between Rectangular Waveguide and Microstrip Line

This paper presents a generalized analysis on aperture coupling between a microstripline and a rectangular waveguide. The orthonormalized modal functions for the microstrip line required for the determination of the equivalent diopole moment are found from its equivalent parallel plate configuration. Expressions for coupling are obtained for transmissions lines with their axes parallel, the lines forming a T-junction and also for cross-guide couplers. Theoretical results show good agreement with the experimental data for all cases under investigation.     

多矩孔菲涅耳衍射的数值模拟

本文由衍射积分公式出发,利用数值模拟方法对多矩孔的菲涅耳衍射进行分析,基于菲涅耳衍射积分法,提出了一种针对多矩孔菲涅耳衍射的数值算法,同时给出了相应的Matlab程序以及仿真结果。从数值分析结果可以看出,该研究结果对于实验验证和计算较为复杂的多矩孔菲涅耳衍射现象具有重要的理论参考意义。     

用多层矩形波导近似计算扁保偏光纤的双折射

本文提出了计算扁保偏光纤双折射的一个近似方法。首先建立了扁保偏光纤的多层矩形介质波导模型,再用类似于Marcatili解矩形介质波导方法,将多层矩形波导分解为两个垂直交叉的多层平板波导,最后求解多层平板波导得到矩形波导的传播常数和双折射。用这一方法计算了双折射与扁保偏光纤结构参数,如应力包层掺硼浓度、椭圆度和归一化频率等的关系曲线,可供设计和工艺人员参考。     

An Adjustable Sliding Termination for Rectangular Waveguide

A new adjustable sliding termination for rectangular waveguide has been developed. The termination is of simple design and can easily be adjusted to have reflection coefficients from zero to nearly unity in magnitude and any desired phase. In addition to the usual applications of adjustable sliding terminations for rectangular waveguide, it provides a suitable design for an adjustable transferor secondary standard of impedance for rectangular waveguide systems.     

Radiating apertures in a corrugated rectangular waveguide

A variational analysis for determining the scattering parameters of an aperture in the plane broad wall of a corrugated rectangular waveguide is described. To effect the analysis, a quasi Green's function for the loaded waveguide is postulated.     

Design of a Power Extractor Using a Rectangular Dielectric Loaded Waveguide

We report on the design of a power extractor using a rectangular dielectric loaded (DL) waveguide. The use of a rectangular rather than a circular DL waveguide can potentially lead to higher output power, since a flat drive beam can then be used to mitigate space charge effects. This power extractor based on the LSM₁₁ mode is predicted to be able to generate 171 MW of power with a 100 nC/bunch drive train of electron bunches separated by 0.769 ns. An output coupler is also designed which is able to extract the generated power to standard waveguides with a 94% coupling efficiency. The propagation of an intense electron beam through a long rectangular DL waveguide is investigated. Results show that, by using a periodic magnetic focusing channel surrounding the waveguide, a 20 MeV, 40 nC beam can propagate up to 129 cm without significant particle losses.     

Discontinuities in a Rectangular Waveguide Partially Filled with Dielectric

The modal spectrum for a rectangular waveguide with a dielectric slab at the bottom of the guide is obtained following the Characteristic Green's Function method developed by Marcuvitz. Then a four-terminal network is found as equivalent to the junction of the partially filled waveguide and an empty rectangular waveguide. An integral equation is written for the electric field at the plane of the junction and variational expressions are derived for the parameters of the four-terminal network connecting the transmission line equivalent to the partially filled waveguide to the transmission line equivalent to the empty guide. A reasonable guess for the electric field at the discontinuity gives approximate values for the parameters of the four-terminal network. These values agree with experiment. The parameters of the network are plotted vs frequency and thickness of the slab.     

Depth of Penetration of Fields from Rectangular Apertures Into Lossy Media (Short Paper)

A widely used device for biomedical applications of microwave energy is the dielectric-loaded waveguide operating in the TE/sub 10/ mode. We have calculated the (1/e) energy penetration depth from such antennas, modeled as rectangular apertures radiating into a lossy medium with dielectric properties resembling those of tissue. The results are presented in nondimensional form from which the characteristics of practical antennas can be estimated. Depending on the dielectric properties of the medium and the size of the aperture, the effective penetration depth can be limited by either the aperture size or the plane-wave penetration depth practical antennas fall between these two extremes. Experimental results confirm the calculations.     

Aperture performance of a double-ridge rectangular waveguide in a phased array

Despite its widely recognized broad-band characteristics, the potential of a double-ridge rectangular waveguide as a phased array element has not been systematically explored. An additional benefit in using this waveguide is its reduced size which permits realization of a compact array lattice for wide angle scanning applications. A number of treatments of ridge waveguide propagation characteristics appear in the literature [1] -[5], but an analysis of the performance of a double-ridge waveguide phased array element has only recently been published [6], [7]. The results presented are based on [6], but they include additional material. The unmatched aperture performance of a rectangular ridge-guide in a number of wide-band phased arrays with quarter-hemispherical coverage, and a single narrow-bandH-plane scan design are examined. A parametric study and comparison of the unmatched aperture performance of a ridged-guide element with that of a rectangular waveguide reflects the capabilities of the double ridged-guide wide-band element in a large phased array. Such parametric study reveals to the designer the active admittance of the unmatched radiating element and leads in a systematic manner to a choice of the ridge-guide geometry and array lattice, to be followed by the determination of a suitable matching structure. This approach contrasts that of [7], which concentrates on demonstrating the feasibility of broad-band matching of a particular dual ridged-element.