Shielded suspended dielectric guide

The dispersion characteristics of a shielded suspended dielectric are computed using mode matching technique. From the dispersion characteristics the dielectric and conductor loss, quality factor and wave impedances are derived. The dimensions of shielded suspended dielectric are same as that of a rectangular metallic wave guide at K_a band.     

Rectangular resonators in inverted microstrip and suspended microstrip

Resonant frequency characteristics of rectangular resonators in a generalized shielded suspended substrate line are analysed using a rigorous spectral domain technique. The computed dominant mode resonant frequency of rectangular resonators in a suspended microstrip with centred dielectric, inverted microstrip and suspended microstrip are presented as a function of various structural parameters. These characteristics are distinct from those obtained for a conventional microstrip rectangular resonator. Experiments are carried out in the frequency range 4-18 GHz to verify the computed resonant frequencies for a suspended microstrip with a centred dielectric using first-order basis functions. The results should find applications in the design of inverted microstrip and suspended microstrip passive microwave and millimetre wave integrated circuits.     

Reciprocal Ferrite Phase Shifters in Rectangular Waveguide (Correspondence)

A recent article by Reggia and Spencer describes a reciprocal ferrite phase shifter for rectangular waveguide, This phase shifter consists of a pencil of ferrite suspended along the central axis of the waveguide by means of a dielectric. The phase is controlled by an applied longitudinal magnetic field. This geometry is shown in Fig. 1. Large amounts of phase shift are produced by this geometry with low insertion loss, and application to antenna beam scanning appears likely, as suggested by Reggia and Spencer.     

Transverse Modal Analysis of Printed Circuit Transmission Lines

Dispersion characteristics of finned rectangular waveguides, finlines, shielded slotlines, shielded microstrip and striplines, and shielded two-coupled slotlines and striplines are formulated by the transverse modal analysis method. A rectangular cavity is formed by placing two electric walls transverse to a uniform transmission-line system. Considering that the wave propagation is in the direction transverse to the transmission line and to the dielectric discontinuities, the rectangular cavity can be viewed as multiple rectangular waveguide sections joined by the discontinuities. The rectangular waveguide modal analysis technique is readily applicable to obtain the dispersion characteristics by matching the boundary conditions at the discontinuities interface. Numerical solutions are obtained using Galerkin's method, and the results are compared with several numerical techniques for various transmission-line systems.     

Design and performance of a new digital phase shifter at X-band

A new digital phase shifter design at X-band is presented. The phase shifter operates based on converting a microstrip line to a rectangular waveguide and thus achieving the phase shift by changing the wave propagation constant through the medium. As a proof of principle, a 3-b phase shifter has been designed and constructed using PIN diode switches. An average insertion loss of 1.95 dB and phase shift error of less than 4/spl deg/ at 10.6 GHz are achieved.     

介质加载双环背脊波导移相器的相—频特性

本文给出介质加载双环背脊波导移相器的传输常数方程,计算了典型参数的相移,和损耗的频率特性。不但给出了最佳的差相移的频率特性,还指出了该器件的优值比普通矩形波导的高,另外,背脊的存在提供了良好的热传导,因此它具更高的平均功率容量。     

Finite-Difference Analysis of Rectangular Dielectric Waveguide Structures

A class of dielectric waveguide structures using a rectangular dielectric strip in conjunction with one or more layered dielectrics is analyzed with a finite-difference method formulated directly in terms of the wave equation for the transverse components of the magnetic field. This leads to an eigenvalue problem where the nonphysical, spurious modes do not appear. Moreover, the analysis inclndes hybrid-mode conversion effects, such as complex waves, at frequencies where the modes are not yet completely bound to the core of the highest dielectric constant, as well as at frequencies below cutoff. Dispersion characteristic examples are calculated for structures suitable for millimeter-wave and optical integrated circuits, such as dielectric image lines, shielded dielectric waveguides, insulated image guides, ridge guides, and inverted strip, channel, strip-slab, and indiffused inverted ridge guides. The numerical examples are verified by results available from other methods.     

一种新型铁电体移相器

介绍了一种用于相控阵雷达的新型铁电体移相器,利用有限元方法对铁电体材料加载波导移相器进行了分析,给出了计算结果。最后讨论了铁电体移相器设计中几个值得关注的重要问题。     

Optimum field theory design of broad-band E-plane branchguide phase shifters and 180° couplers

Optimum rectangular waveguide E-plane branch guide phase shifters and 180° branch guide couplers are designed with the rigorous method of field expansion into normalized eigenmodes. The design includes both the higher order mode interaction between the step discontinuities and the finite step and branch heights. The phase shifter design applies the Schiffman principle to branch guide couplers where two ports are short-circuited. The 180° coupler design combines the advantage of the broadband potential of multiple-branch couplers with the low-insertion-loss qualities of E-plane stub-loaded phase shifters. A computer-optimized phase shifter prototype for the waveguide Ku-band (12-18 GHz) shows a 90°±1° differential phase shift with reference to an empty waveguide within about 23% bandwidth. Five-branch three-stub coupler prototypes, designed for 3±0.2 dB coupling, for the waveguide Ku- and Ka-bands (26-40 GHz) achieve a 180°±1° differential phase shift at the output ports within about 19% bandwidth, as well as more than 30 dB isolation and return loss. The theory is verified by measured results     

Shielded rectangular dielectric wave guides for millimeter wave integrated circuits

The dispersion characteristics of Insulated non-radiative dielectric guides are computed using mode matching technique. From the dispersion characteristics the dielectric loss conductor loss and wave impedances are derived. Effect of metallic walls on trapped insulated image guide are also discussed. The dimensions of Insulated non radiative dielectric guide are same as that of rectangular metallic wave guide at ka band.     

A unique method for reducing losses of bends in dielectric optical wave guide

The dielectric optical wave guide is finding growing attention at millimeter wave frequencies. However the dielectric optical waveguide radiates at bends and thus transmission loss increases. These radiations are in the outword direction of bends. This output radiation at output bends arises due to change in phase velocities of the propagating wave at the centre of the dielectric guide and the phase velocity at the outer surface of the dielectric guide. A unique methiod is suggested to avoid these radiation losses.Experimental results are also shown at microwave frequencies.     

An X-Band Ferroelectric Phase Shifter

An X-band electrically-tunable ferroelectric phase shifter has been constructed. The phase shifter is reciprocal and consists of a thin ferroelectric slab completely filling the transverse plane of a rectangular waveguide with suitable dielectric matching sections placed symmetrically about the slab forming a band-pass filter. Phase shift is controlled by applying a dc electric field to the ferroelectric. The measured characteristics of this device indicate that incremental phase shifts of 40/spl deg/ to 50/spl deg/ are attainable over a bandwidth of 400 Mc centered about 9.3 kMc with insertion losses ranging from 2 to 6 db. Since the phase shifter does not require a magnetic field for operation, the device can be biased with inexpensive, light-weight equipment requiring negligible dc control power, and the response time can be expected to be fast.     

Numerical Analysis of the Rectangular Dielectric Waveguide and its Modifications

Dielectric waveguides suitable for millimeter and submillimeter wave integrated circuits are analyzed by applying the generalized telegraphist's equations. The dielectric waveguides treated in this paper are the rectangular dielectric image line, the cladded rectangular dielectric image line, the insulated image guide, and the strip dielectric guide. Numerical results of the propagation constant, the power distribution, and the field configuration in these dielectric waveguides are presented. Values for the propagation constants obtained by our method are compared with other theoretical results. Although this work is based on a closed waveguide model, it may be applicable to wide classes of dielectric waveguides with arbitrary dielectric profiles and cross sections.     

铁氧体矩形波导双模传输特性的研究

根据非简并态耦合波方程，对充满磁化铁氧体的矩形波导双模旋磁传输效应进行了系统分析，解出了在各种磁化状态下的传输本征模式，讨论了本征模的极化状态。分析了矩形波导移相器的设计原理。     

A 20 GHz Steerable Array Antenna Using 3-bit Dielectric Slab Phase Shifters on a Coplanar Waveguide

A simple steerable array antenna is designed and developed using a movable dielectric phase shifter. The change of effective dielectric constant at different dielectric slab positions on a coplanar waveguide is used as the phase shifter. The impedance matching and desired phase shift conditions are satisfied at two slab heights, and the reflection is designed to be minimized at these slab positions. The low-loss dielectric material is used as the dielectric slab and is placed close to a coplanar transmission line with airgap. The 4times4 steerable array antenna with the phase shifters is designed and fabricated at 20 GHz. The H-plane radiation patterns are measured at different phase shift positions and compared with the expected results     

Propagation properties of ferromagnetic insulator guide

In order to realize new ferrite planar devices for applications at millimeter-wavelength frequencies, the authors have developed nonreciprocal ferrite devices schemes for incorporating ferromagnetic layers in dielectric insulator guide geometries. Their research program involves both the calculation and the measurement of device characteristics. For the calculation, a method of effective permeability, in which the permeability is a tensor, is introduced to characterize the ferrite material. The propagation properties of the insular guide are calculated by using a single-mode approach. The calculated results for dispersion, dielectric, and conductivity losses show resonant behavior with the application of a magnetic bias field for a guide configuration in which the ferrite replaces the insular dielectric. Ferrite phase shifters, filters, isolators, and circulators are potential applications of this guide configuration. For the experimental part of the study, wave dispersion and attenuation were measured in a purely dielectric insular guide from 26.5 to 40GHz. In addition to these experiments wave attenuation was measured as a function of magnetic bias field for the case where a hexagonal ferrite platelet was mounted on the ground plane near the insulator guide. General agreement is found between calculated and measured attenuation     

Rectangular Waveguide Switches (Correspondence)

Since the first disclosure by Reggia and Spencer of the rectangular waveguide phase shifter, a number of investigators have presented qualitative analyses describing ob-served performances. In general, these authors agree on two phenomena that occur. First, upon application of a longitudinal magnetic field to the ferrite (phase-shifter geometry shown in Fig. 1), there is a "trapping" process whereby the RF field is increasingly concentrated in the ferrite acting as if it were a "dielectric" waveguide. Second, there is a mode-conversion process that takes place simultaneously (probably a circularly polarized wave in the ferrite rod) that gives rise to an electric-field component in the ferrite region orthogonal to the electric field in the empty waveguide (TE/sub 10/ mode).     

双模铁氧体器件的理论和设计(二)

根据非简并态耦合波方程，对充满磁化铁氧体的矩形波导双模旋磁传输效应进行了系统分析，解出了在各种磁化状态下的传输本征模式，讨论了本征模的极化状态。分析了矩形波导移相器的设计原理。     

Quasi-static analysis of electrooptic modulators by the method oflines

A quasi-TEM analysis using the method of lines is implemented to calculate the electric field anywhere within a layered guided wave structure at appropriately low frequencies. The analysis provides the electric fields and transmission-line parameters for a shielded structure having any number of coplanar electrodes within an arbitrary number of anisotropic dielectric layers, the principal axes of which are parallel to the axes of the structure. The practical application considered is the calculation of the phase shift of a guided optical wave within an electrooptic modulator that has a dielectric buffer layer between the electrodes and electrooptic substrate     

用于移动通信电调天线的宽频移相器*

提出一种用于移动通信电调天线的宽频移相器。该移相器通过介质滑动来改变相位,通过局部阻抗匹配保证介质滑动过程中各支路阻抗的小幅波动,实现稳定的功率分配。仿真和实测结果表明,该移相器在1. 71GHz-2. 69 GHz 范围内,电压驻波比(VSWR)小于1. 25,传输系数波动不超过依1dB,在最大相移位置,相位离散性在7.5%以内。该移相器具有工作频带宽、通用性强、布局紧凑、体积小等优点。