Analysis of E-H plane tee junction using avariational formulation

A three-port equivalent network for an E-H plane tee junction is determined taking into account the effect of waveguide wall thickness and considering the contribution of the dominant mode to the imaginary part of the self-reaction. The parameters of the three-port equivalent network are determined. From a knowledge of the equivalent network parameters, the net impedance loading, reflection coefficient, and coupling are evaluated for an E-H plane tee junction. A comparison between theoretical and experimental results is also presented     

Superconducting millimeter-wave E-plane filters

The authors report on the measured performance of a three-pole E-plane filter constructed from high-T_c superconducting bulk materials at 34.5 GHz. Experimental results are presented for the insertion loss and return loss of the filter at 77 K. The problems associated with the use of bulk materials at the millimeter-wave range are addressed. Other possible superconducting waveguide filter configurations are proposed. While the experimental results are taken at low input power level, the current distribution inside the filter structure is calculated, and the power handling capability of the superconducting filter is discussed     

E-polarized scattering from a conducting rectangularcylinder with an infinite axial slot filled by a resistively coateddielectric strip

The potential use of resistive films for damping the resonance spikes observed in the radar cross section (RCS) spectrum of a partially open rectangular cavity is investigated using a recently developed finite-difference-time-domain (FDTD) method that utilizes the resistive-sheet boundary condition for the modeling of resistive films. Backscattering data obtained in the first resonant region for an E -polarized plane wave normally incident into the slotted side of the cavity are presented. It is shown that resonance behaviors can be eliminated completely with a low-resistance film that attenuates significantly the impinging wave. Poorer resonance damping performance is observed as the film resistance increases because more of the field is allowed to penetrate into the cavity. For the latter case, the presence of the resistive film lowers the Q-factor of the slotted cavity such that the resultant resonance spectrum is lower in strength and broader in bandwidth     

Robustness of mean E{X} and R charts

The effect of nonnormality on E{X} and R charts is reported. The effect of departure from normality can be examined by comparing the probabilities that E{X} and R lie outside their three-standard-deviation and two-standard-deviation control limits. Tukey's λ-family of symmetric distributions is used because it contains a wide spectrum of distributions with a variety of tail areas. The constants required to construct E{X} and R charts for the λ-family are computed. Control charts based on the assumption of normality give inaccurate results when the tails of the underlying distribution are thin or thick. The validity of the normality assumption is examined by using a numerical example     

Scattering of E-polarized waves from conducting strips inthe presence of a magnetically uniaxial half-space-a singular integralequation approach

A method based on the theory of singular integral equations (SIE) is presented for treating analytically scattering by perfectly conducting infinitely long strips in the presence of a magnetically uniaxial half-space. A uniform plane wave, polarized parallel to the strip axis, is incident from the isotropic region. As a prerequisite to this approach, the E-mode scalar Green's function of the structure is developed. Use of the reciprocity theorem then leads to a SIE for the current density induced on the scatterer's surface. The solution of the SIE is carried out in the case of a strip parallel or perpendicular to the interface, either located above or embedded in the anisotropic space. Numerical results for the induced current density and for the scattered far field in a variety of cases are presented in graphical form     

Oscillators and amplifiers in integrated E-plane technique

An overview is presented of solid-state oscillators and amplifiers realized in E-plane technology. The circuit topology, basic design procedures, and performance characteristics are described and compared. Gunn oscillators, IMPATT oscillators, transistor oscillators, injection-locked Gunn oscillators, and transistor amplifiers are surveyed. Gunn and transistor oscillators have been realized successfully for frequencies from 10 to 110 GHz, thus covering almost the entire frequency range suitable for E-plane technology. IMPATT oscillators are difficult to design and to reproduce in quasi-planar form because of the high impedance ratio that must be overcome by the circuit. E-plane FET amplifiers have been built for frequencies up to 60 GHz     

Computer-aided design of E-plane waveguide passivecomponents

The newly developed numerical analysis method for the inductive discontinuities in rectangular waveguides is presented. It can be used to analyze the scattering properties of E-plane uniform conductor-dielectric inserts in rectangular waveguides. These inserts are of arbitrary cross section and number. The calculation accuracy and speed are improved by a combined analytical-numerical approach. Some practical applications are given demonstrating its engineering usefulness     

Improved theory for E-plane symmetrical tee junctions

L. Lewin's theory (1975), which describes an E-plane symmetrical tee junction by an equivalent circuit with only three parameters, is examined. It is shown that although the theory is formally correct, its circuit parameters depend on the amplitudes of reflected waves. An improved theory corrects this fault     

Optimum design of waveguide E-plane stub-loaded phaseshifters

Broadband low-insertion-loss E-plane stub-loaded rectangular waveguide phase shifters are designed with the method of field expansion into normalized eigenmodes, which includes higher-order mode interaction between the step discontinuities. Computer-optimized three-stub prototypes of 90° differential phase shift with reference to an empty waveguide of appropriate length, designed for R140-band (12.4-18 GHz) and R320-band (26.5-40 GHz) waveguides, achieve typically ±0.5° phase shift deviation within about 20% bandwidth. For two-stub designs, the corresponding values are about +2.5°/-1° and 17%. Both designs achieve minimum return loss of 30 dB. The theory is verified by measurements of a compact R120-band (10-15 GHz) waveguide phase shifter design example milled from a solid block, showing measured insertion loss of about 0.1 dB and about +2.5°/-0.5° phase error between 10.7 and 12.7 GHz     

Spectral-domain analysis of E-plane waveguide tomicrostrip transitions

The spectral-domain technique and a residue calculus theorem are used to compute the input impedance of a microstrip transition to a rectangular waveguide. The transition consists of a printed circuit board inserted into a waveguide housing along the E-plane. The effects of the dielectric layer are considered in the present analysis. The behavior of the input impedance of the transition is studied with respect to the critical dimensions of the probe length and backshort location. Calculated results by the new formulation agree well with those computed using an integral equation and those measured at Ka -band frequencies     

Nonuniform currents on a wedge illuminated by a TE plane wave

Closed-form expressions for nonuniform currents on a perfectly conducting, infinite wedge illuminated by transverse electric (TE) plane wave are presented. These expressions are derived by requiring that they coincide with the current predicted by the asymptotic diffraction method far from the edge and, further, that they agree with the current predicted by the eigenfunction solution at the edge. The angle of incidence is arbitrary and our expressions remain valid even for glancing angles of incidence when either one or both faces of the wedge are in the vicinity of a geometric optic (GO) boundary. Formulas presented here are simple involving the well-known modified Fresnel functions but are not uniform. Exact expressions for nonuniform currents are available for the two special cases of half-plane and infinite plane. For these special cases, our solution reduces to the exact solution. Currents computed using the expressions developed here are compared with currents computed from the eigenfunction solution of the wedge. Good agreement is obtained throughout.     

p-i-n diode control devices in E-plane technique

The status of the use of p-i-n diode control devices in the E -plane technique, especially in integrated finline configurations, is reviewed. The circuit topologies, operating principles, and design considerations for state-of-the-art switches, attenuators, and digital modulators are discussed, and typical performance characteristics are presented. The superior performance of these components confirms that finline is the appropriate transmission medium for the realization of millimeter-wave p-i-n diode switches and attenuators in the low-power regime (up to some 10 W of CW power), where beam-lead diode devices can be used. By properly matching these devices to their finline embedding network, excellent broadband characteristics can be achieved     

Prediction of the E and H fields produced by theSwiss mobile EMP simulator (MEMPS)

The author discusses a simple analysis for determining the electromagnetic fields produced by the MEMPS simulator. A transmission line solution for the currents flowing on the simulator structure is obtained, taking into account both the resistive loading along the simulator and the dispersive nature of the earth under the simulator. Once the current distribution is determined, the fields at an arbitrary location are found by integrating the fields produced by an electric current element located over the lossy air-earth interface. Using this model, a procedure for estimating the fields at an arbitrary location within the simulator is described. This requires a knowledge of the primary transient E and H field components at a reference point near the simulator, or equivalently, a knowledge of the incident E or H field at this point. Results of this study indicate that it is possible to predict the simulator fields at other points, based on the reference fields and the calculational model     

Scattering parameters of E-plane printed opposite fin inwaveguide

An analysis of the E-plane printed opposite fin in a waveguide is presented. The current distribution existing on the metal fin is obtained through a variational technique that utilizes the extremization process. The eigenvalue functions derived from the transverse resonance condition are used to include the effects of the dielectric layer. The computed data for a simplified case with Duroid substrate are compared with those obtained by means of the spectral-domain method. Based on the calculated results, a band-reject filter has been designed and tested at Ka-band. Good agreement on the filter response has been observed between theory and measurement     

NONUNIFORM CURRENTS ON A CONDUCTING WEDGE ILLUMINATED BY A TM PLANE WAVE

Closed-form expressions for nonuniform currents induced on a perfectly conductinginfinite wedge illuminated by a TM plane wave are presented.Results computed by using theseexpressions are in good agreement with ones of the eigenfunction solution of the wedge.     

Field theoretical treatment of E-plane waveguide junctionswith anisotropic medium

E-plane waveguide junctions containing an anisotropic medium are analyzed. The analysis is based on the equivalence principle and on cavity field expansions. Using the equivalence principle, magnetic surface currents are introduced at the imaginary boundaries chosen between the central region of the junction and the waveguides. The electric displacement D in the junction is expressed in terms of a solenoidal set and an irrotational set. Matching the tangential magnetic field at the imaginary boundaries leads to a matrix equation, the unknown of which are the amplitudes of the scattered waveguide modes. Using this method, the performance of E-plane waveguide junctions with full-height and partial-height ferrite post is analyzed. The influence of the completeness terms G_oq on the numerical results of an empty E-plane Y-junction is shown. The numerical results are compared with previously published experimental and theoretical results     

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     

Computer-aided design of evanescent-mode waveguide filter withnontouching E-plane fins

The authors present a computer-aided design algorithm for the analysis and design of an evanescent-mode bandpass filter with nontouching E-plane fins. The theoretical analysis is based on the generalized scattering matrix technique in conjunction with the spectral-domain approach and mode-matching method. The technique used takes into account the dominant as well as the higher-order effects. The measured filter responses in the Ka-band are in good agreement with those obtained by this analysis     

A discussion of E-pulse method and Prony's method forradar target resonance retrieval from scattered field

An efficient version of the E-pulse method is discussed and generalized in the context of radar target pole retrieval from the scattered field. Its relation to the generalized Prony's method is investigated. It is shown that the E-pulse method can be efficiently implemented using a smoothing-and-sampling procedure and a Prony's approach. The tradeoff between noise insensitivity and computational burden influenced by various parameters is pointed out