TE Modes of the Dielectric Loaded Trough Line

The properties of TE modes on a dielectric loaded trough waveguide have been investigated. In the case of the dominant mode of this line (TE/sub 20/), families of design curves giving the field distribution, guide wavelength, power handling capability, wall losses, and dielectric losses as a function of operating wavelength, waveguide dimensions and dielectric constant are presented. For a loosely bound wave, the losses are comparable to those of conventional rectangular waveguide and the power handling capability is an order of magnitude greater. The apparatus and procedure used to measure guide wavelength, rate of field decay in the transverse direction, and attenuation are described. The measured performance is in close agreement with the theoretically predicted characteristics.     

矩形波导中主模电磁波传播特性研究

矩形波导主模电磁波是波导传输中使用最多的模式。为了能深入了解其传播特征。从波导的截至波长入手,讨论了电磁波单模传播的条件。得出结论：主模传播需要电磁波波长和波导尺寸之间满足一定关系。推导出主模电磁波的场方程,利用该场方程,结合一定尺寸的矩形波导管,模拟出一定频率的主模电磁波分布图,进而总结了主模电磁波传播的主要特征。这...     

Propagation in Dielectric Slab Loaded Rectangular Waveguide

Propagation in dielectric loaded rectangular waveguide is investigated theoretically for varying slab thickness and dielectric constant. The slabs are placed across the center of the waveguide in the E plane. This geometry is found to offer bandwidths in excess of double that of rectangular waveguide for dielectrics having dielectric constants of approximately 18. Power handling capacities which are double or triple that of standard waveguide are achievable using the dielectric loaded waveguide. In addition to the theory, design curves of bandwidth, guide wavelength, cutoff wavelength, impedance, power handling capacity, wall losses, and dielectric losses are presented and compared to experiment where possible.     

The Channel Waveguide (Correspondence)

A waveguide propagating the TE/sub 10/ mode can carry more power than the normal rectangular waveguide if it has a symmetrically placed channel in the E-plane as shown in fig. 1. The greater height of the channel in the center of the waveguide will allow a higher voltage to be applied before dielectric breakdown occurs. The TE/sub 10/ cutoff wavelength /spl lambda//sub c/ was investigated using the methods of Iashkin and Cohn to find out if the cutoff wavelength of the channel waveguide was equivalent to that of the rectangular waveguide /spl lambda//sub cr/.     

新型单脊矩形波导传输特性研究

文章利用亥姆霍兹方程的有限差分格式,研究了在新型单脊矩形波导中,脊在中心位置且几何尺寸变化时对传输特性的影响.计算了脊的尺寸变化时的截止波长λc和单模带宽B(λc/λc1),并给出了TE10和TE11模式的场结构图以及变形对截止波长和单模带宽影响的相应曲线.通过与传统单脊矩形波导的对比,指出了新型单脊波导传输特性的优缺点.     

Two-Mode Waveguide for Equal Mode Velocities

A rectangular waveguide, with a T-septum attached to one of its side walls, is capable of supporting two modes with equal-phase velocities. Stationary expressions are developed for the cutoff wavelengths of these two modes as functions of the cross-sectional dimensions. A Rayleigh-Ritz procedure is used to produce families of curves relating each cutoff wavelength to the septum dimensions; intersections of corresponding curves establish theoretically those combinations of dimensions that permit the two modes to propagate at a common velocity. Experimental corroboration of the theory is also presented.     

Propagation of TE Modes in Dielectric Loaded Waveguides

The propagation of TE/sub no/ modes in rectangular wave-guides that contain two dielectric slabs parallel to the narrow wall and extending over the full height of the guide is investigated. Waveguide and dielectric are assumed to be lossless and infinitely long. Apart from these restrictions, the dielectric slabs may have arbitrary thickness, position, and dielectric constant. The analysis is restricted to TE/sub no/ modes with the E-field parallel to the narrow guidewall. The guide containing only one dielectric slab is covered by this analysis. The even modes n = 2, 4, 6, . . . of the guide with two slabs correspond to the odd modes n' = n/2 = 1, 2, 3, . . . of the guide with one slab half the width of the guide with two slabs. For six relative dielectric constants (/spl epsilon/= 2.25, 4.00, 9.00, 12.25, 16.00, 25.00) the cutoff frequencies for TE 10, 20, 30, 40, 60 modes and the normalized propagation constants for TE 10 and TE 20 modes between their respective cutoff frequencies and a frequency slightly above the second- and fourth-order mode cutoff frequency for the empty guide, respectively, have been computed for a large range of slab thicknesses and slab positions. Selected results are presented graphically. These results are discussed. The parametric dependence of field distributions, of normalized characteristic impedances, of the ratio of cutoff frequencies (fractional bandwidth), and of the ratio of magnetic field components (ellipticity) are illustrated.     

填充介质倒梯形脊波导截止特性的有限元分析

为了寻找最佳截止特性的填充介质脊波导结构,提出了填充介质倒梯形对称双脊波导.采用有限元法借助MATLAB软件计算了填充介质倒梯形对称双脊波导在TE模式下的截止特性,即主模截止波长和单模带宽.绘制出主模场结构图,并分析脊波导截止特性与填充介质相对介电常数之间的关系,给出了关系曲线图.这些结果将对填充介质波导的设计和工程应...     

Artificially integrated synthetic rectangular waveguide

A synthetic rectangular waveguide (SRW), which consists of two electrical sidewalls and two parallel periodical structures placed at the top and bottom surfaces of the waveguide, is presented. The SRW is made by multilayered integrated circuit processes, which typically have large ratios of SRW lateral dimensions to substrate thickness. Two theoretical methods, finite-element method and deembedding of composite structure consisting of SRW and mode converters, are applied to investigate the propagation characteristics of the SRW. Application of the dispersion characteristics of the two-dimensional periodical structures coupled with appropriate mode converter designs leads to results in SRW designs supporting TE/sub 10/, TM/sub 00/, and TM/sub 10/ modes. Measurements and the two theoretical approaches indicate that the slow-wave factor is 4.9 and Q-factor is 260 at 6.85 GHz for the TE/sub 10/ mode propagation with a cutoff frequency of 4.10 GHz (0.348 factor of cutoff frequency of conventional rectangular waveguide using the same material and dimensions). The theoretical data show the TM/sub 00/ mode to have a slow-wave factor of 1.8, Q-factor of 187.6 at 11.4 GHz, and cutoff frequency of 10.2 GHz. The TM/sub 10/ mode has a slow-wave factor of 1.98, Q-factor of 187.6 at 12.5 GHz, and cutoff frequency of 10.4 GHz.     

Wide Band Metallic Waveguide With In-Line Dielectric Rods

Conventional rectangular metallic waveguides are seldom used at frequencies higher than twice the cutoff frequency because of higher mode propagation. Single-mode propagation is available for a metallic waveguide with arrayed dielectric rods at the center of the waveguide in the frequency under twice the cutoff frequency region using the TE₂₀ mode, and in the frequency over twice the cutoff frequency region using the TE2o mode. If the metallic waveguide and dielectric loss tangent are assumed to be WR-90 (f_c ap6.55 GHz) and 3times10^-4, respectively, then the attenuation constants are smaller than 0.25 dB/m in the frequency range from 7 to 10 GHz, 15 to 16.5 GHz, and from 17.2 to 21 GHz.     

含单负材料对称三层平板波导的模式特性

由电磁场的波动方程和边界条件建立了单负材料作为芯层的对称三层平板波导的模式本征方程,用图解法研究其色散特性。研究发现,单负介质波导不支持快波的传播,只支持表面波的传播。在负磁材料平板波导中只存在TE表面模,不存在TM表面模。分析了在负磁材料平板波导中TE模受磁导率的比值-μ2／μ1和波导参数的影响,给出了横向场分布图。在-μ2/μ1〈1时,偶对称只有TE0表面模存在,奇对称只有TE1表面模存在,高阶模式并不存在,且两种模式都没有低频截止;-μ2/μ1〉1时,TE1表面模始终不出现;TE0模的存在与否和波导参数有关,在一定条件下TE0模可出现双模并存。给出的结果可望对表面波器件的设计提供理论基础。     

On the Mode and Square Correspondence Between Circular Multimode Tapered Waveguides

In an axially straight multimode circular waveguide taper excited with a pure TE/sup /spl circle// /sub 11/ dominant mode, the first and only converted mode at and near cutoff is the TM/sup/spl circle// /sub 11/ mode. It is shown that in an axially straight multimode square waveguide taper excited with a pure TE/sup/spl square// /sub 10/ dominant mode, the TM/sup/spl square// /sub 12/ mode corresponding to the TM/sup/spl circle// /sub 11/ mode in circular case is not the only first converted mode at and near cutoff. The overall behavior or coupling mechanism of waveguides is similar whether the waveguide is rectangular, square, circular, or elliptical: i.e., the overall coupling coefficient at cutoff of a converted mode or modes approaches an ininfinity of the order 0/sup -1/4/.     

Nonreciprocal Remanence Phase Shifters in Rectangular Waveguide

Three types of nonreciprocal remanent phase shifters in rectangular waveguide are described which are approximated by a simple model consisting of twin ferrite slabs symmetrically placed in rectangular waveguide and separated by a dielectric rib. The model has been analyzed with the assumption that a fundamental TE mode wave propagates in the structure. Simultaneous solution of Maxwell's equations in the three regions of dielectric, ferrite, and air within the waveguide enables the characteristic equation to be formed. The characteristics of the model have been obtained with the aid of a computer as a function of dimensions, dielectric and magnetic constants, frequency, and power. The theoretical results are compared with experimental data obtained on a double toroid structure. Correction factors applied to the experimental data, which are necessary to account for differences between the practical structure and the ideal model, are discussed.     

对称单负材料平面波导的波导模

基于经典电磁理论建立了芯层为单负材料的对称三层平板波导的导波方程,采用图解法研究了该波导中的TE和TM波导模,分析了TE波导模和TM波导模会受波导参数μ1/μ2和R的影响,给出TE模和TM模解的横向场分布图.结果显示,在单负材料的对称三层平板波导中只存在慢波导模,TE慢波模只能在磁负材料中传播,TM慢波模只能在电负材料...     

A High-Power S-Band Filter (Correspondence)

This note describes the measured performance of a high-power S-band "waffleiron" filter. Techniques for designing varying-impedance corrugated waveguide filters in rectangular waveguide have been available for some time [1 ]. If propagation is restricted to the dominant TE/sub 10/ mode, these filters have wide well-matched pass bands and wide high-attenuation stop bands. Unfortunately, the filters may have spurious transmissions in the stop band when power is incident upon them in other modes, such as TE/sub 20/ or TE/sub 30/, if the guide wavelength of these modes at the stop band frequencies is equal to the guide wavelength of the TE/sub 10/ mode at the pass-band frequencies of the filter.     

Rigorous Analysis of the Scattering of Surface Waves in an Abruptly Ended Slab Dielectric Waveguide

The reflection and the scattering properties of even TE and TM surface waves incident in an abruptly ended dielectric slab waveguide are analyzed. The discontinuity is regarded as a junction between two open waveguides namely the dielectric slab waveguide and the free space waveguide. The boundary conditions acting together with the orthogonality provide singular coupled integral equations on the discrete and the continuous wave amplitudes at the discontinuity. These singular coupled intergral equations with Cauchy kernels and infinite limits of integration are solved by iteration via the Neuman series. Numerical results are presented for the reflectivity of the even TE/sub 0/ and TM/sub 0/ fundamental modes, together with their mode conversion on even TE/sub 2/ and TM/sub 2/ in a slab where two guided modes can propagate. Reflectivity and mode conversion of higher order excitations are also investigated     

Modes of a symmetric slab optical waveguide in birefringent media, part II: Slab with coplanar optical axis

We study the modes of a symmetric thin-film slab waveguide composed of birefringent crystalline material in the film and in the equivalent substrate and superstrate. In addition we assume that the optical axes of the uniaxial materials of film and substrate are parallel to each other and also parallel (coplanar) to the plane of the film. This simple anisotropic waveguide has interesting properties. It supports only hybrid modes but in the limit of propagation along the optical axis and at right angles to it the modes become almost of the TE and TM type. Moreover, some of the modes become leaky waves as they propagate at increasingly larger angles relative to the optical axis of the dielectric material. For guides made of materials whose ordinary refractive index nois larger than the extraordinary index ne, the extraordinary wave modes, which approximate TE modes, become leaky; and forn_{e} > n_{o}, the ordinary wave modes, which approximate TM modes, become leaky. The leakage losses are large near a "critical angle," where leakage begins to appear but may be insignificant at larger angles, measured between the optical axis and the direction of propagation.     

Electrodynamic analysis of eigenmodes in a rectangular waveguide with two L-shaped septa

A technique of electrodynamic calculation and computer-aided simulation of the structure of the electromagnetic fields of TE and TM waves in a rectangular waveguide with two L-shaped ridges and a lossless air filling is presented. The problem is solved by means of the partial domain method with allowance for the edge singularity of the electromagnetic field. Cutoff wave numbers, the structure of the electromagnetic fields of various TE — and TM-wave modes in the cutoff regime, the characteristic impedance, and the breakdown power for the fundamental waveguide mode are calculated.     

Propagation Constants in Rectangular Waveguide Partially Filled with Dielectric (Correspondence)

There is considerable current interest in the production of guided electromagnetic waves having phase velocities equal to or less than the speed of light in free space (for example, in the design of traveling-wave slot antennas and of devices involving electron traveling-wave interactions). Such phase velocities can be obtained conveniently by partially loading a rectangular waveguide with dielectric material. In antenna work particularly, because of the field configurations, it is usually desirable to place the dielectric interface so that it is parallel to the broad face of the waveguide, as indicated in Fig. 1. The calculation of phase velocities in such a waveguide has been considered in the literature, and there is published information on some of the cutoff frequencies, but (since in this case there is no convenient relationship between the cutoff frequencies and the propagation constants) there has been little detailed information available concerning the phase velocities as a function of waveguide proportions and dielectric material. Thus a compilation has been made of such information for the dominant (hybrid) mode.     

Modal Inversion in Circular Waveguides---Part II: Application to Latching Nonreciprocal Phasers

The characteristics of the nonreciprocal phase shifter (phaser) configuration, consisting of a circumferentially magnetized circular toroid in circular waveguide, have been investigated theoretically. By suitably filling the toroid center with a material having a high dielectric constant, it is possible to reverse the normal order of the cutoff frequencies of the TE/sub 11/ and the operating TE/sub 01/ modes. The enhanced modal purity resulting from this inversion could yield significant improvements in the performance of practical phasers. The characteristic equation has been derived for the general case of a magnetized toroid in a circular waveguide, with dielectric material in both the central region and external to the toroid. The equation is valid for an arbitrary range of dielectric constants and magnetization. Differential phase shift calculations have been made specifically for operation within the modal inversion window. It is found that adequate differential phase shifts are obtained, even under the restrictions on geometric dimensions and range of dielectric constants imposed by the inversion requirements.