A rectangular beam waveguide resonator and antenna

A closed microwave resonator is derived from the beam waveguide of rectangular symmetry. The resonator is essentially a metal box with one curved wall and approximate dimensionslambda/2bylambda/3by20lambda, wherelambdais the free-space wavelength. Each beam waveguide mode is shown to resonate at a distinct frequency. When apertures are cut in one wall of the resonator a line source antenna is formed. Since then = 0andn = 1beam modes have field distributions which are, respectively, a Gaussian and the derivative of a Gaussian, the radiation patterns produced are of interest in monopulse radar and tracking. A 9 GHz resonator antenna was built, and its measured radiation patterns confirm the theory.     

Full multimodal analysis of an open rectangular groove waveguide

In this paper, a full multimodal analysis of an open rectangular-shaped groove waveguide is presented for both TE and TM modes. The method of solution involves the formulation of the problem in terms of an integral-equation representation to which a Galerkin approximation, which incorporates the anticipated singularities at the edges of the guide, is then applied. The method proves to be extremely accurate and numerically efficient to compute, and results are presented for both the lower and higher order modes     

Excitation of an open resonator coupled with a waveguide via a slot in a mirror

A technique and results of the solution of the problem on excitation of an open mirror resonator coupled with a waveguide via a slot in one of the mirrors are presented. The effect of the coupling slot on the radiation loss is analyzed. The results obtained with the help of a rigorous approach and approximate techniques are compared.     

Field analysis of rectangular waveguide open junction

The problem of a rectangular waveguide open junction is investigated using field theory and the relevant model of two normally intersected, infinite parallel-planes waveguides. Evanescent waveguide modes generated by waveguide wall edges and/or the discontinuity in dielectric are taken into account; an infinite set of equations is derived, where the mode coupling is given by the dielectric slab modes. Proper pole handling is discussed, and a solution for the system is given. Expressions are derived for the reflected, transmitted, and radiated power, which are shown to be sufficiently reliable in the domain of practical interest, regarding the width and the dielectric loading of the gap. The analysis shows that a substantial fraction of the microwave power leaks from the dielectric gap, confirming the absolute necessity of using a choke-flange at the waveguide junction     

Broadband transition between half mode substrate integrated waveguide and rectangular waveguide

A broadband transition between a half mode substrate integrated waveguide and a rectangular waveguide with an antipodal fin-line in its quasi-TEM mode is presented. Experimental results show about 1.3 dB insertion loss and below 215 dB return loss for a back-toback double transition over 10 GHz bandwidth from 26.5 to 40 GHz (the single transition insertion loss is about 0.65 dB). The transition may be used in low-loss and low-noise front-end circuits of the microwave and millimetre-wave bands.     

Broadband substrate integrated waveguide to rectangular waveguide transition with fin-line

A novel broadband transition from a substrate integrated waveguide to a rectangle waveguide with an antipodal fin-line in its quasi-TE mode is presented. Impedance match and field mode gradual changing of transition circuits have been carefully analysed and performed. Experimental results show about a 1.6 dB insertion loss and greater than 12 dB return loss for back-to-back transitions over 10 GHz bandwidth from 26.5 to 40 GHz, so single transition insertion loss is about 0.8 dB. The transition is proposed for low-loss front-end circuits in the millimetre-wave band.     

Oliner models for quasioptical resonator to rectangular waveguide coupling elements

It has been shown that Oliner models, traditionally used for the analysis of microwave integrated circuits, can be applied to the calculation of electrodynamic characteristics of elements for coupling open resonators with rectangular waveguides. The experiments have indicated a high accuracy with the calculation technique developed.<>     

Choice of collocation nodes used in the analysis of an open rectangular dielectric waveguide

The collocation method applied for the electrodynamic analysis of an open rectangular dielectric waveguide is considered. The mathematical apparatus of the correlation theory is used to choose the distribution of collocation nodes. The dispersion equation for the fundamental mode of the structure is solved, the convergence of the solution is investigated, and the electromagnetic-field components on the medium interface are calculated.     

Quasi-optic excitation of an open resonator

A technique and results of solution of the problem on plane-wave excitation of an open quasioptic resonator and a quasi-optic resonator located in an oversize waveguide are presented. Structures with various shapes of the mirror are investigated. The results obtained with the help of the proposed technique are compared with the results obtained by means of an approximate approach.     

A nonreciprocal tunable waveguide directional filter using aturnstile open gyromagnetic resonator

The 4-port waveguide directional filter is a classic network in microwave engineering. The purpose of this paper is to describe one gyromagnetic version using an open gyromagnetic resonator in a dielectric-filled cavity. A property of the circuit is that it behaves as a 4-port circulator with one direction of circulation at one split frequency of the resonator and with the other direction for the other split frequency. An insertion loss between the coupled ports below 1.50 dB and an attenuation or isolation of typically 15 dB between the decoupled ports over most of the tuning range of the filter have been achieved. Its 3-dB bandwidth is typically 65 MHz. A typical tuning range of more than 1 GHz centered at about 10.5 GHz has been separately realized for each split branch     

Scattering at an offset circular hole in a rectangular waveguide

A solution is given for the problem of scattering at an offset circular to rectangular junction and at a thick diaphragm, with an offset circular aperture, in a rectangular waveguide. The method used is mode matching for computing one discontinuity. The difficulty arising from the fact that the eigenmodes of the two waveguides are known in different coordinate systems is overcome by simple transformation for the evaluation of overlap integral between the eigenmodes of each waveguide. Experimental results validate this method     

Analysis of a rectangular waveguide isolator

Isolator conditions are derived for a rectangular waveguide in which magneto-optical and anisotropic dielectric crystals are integrated for reciprocal and nonreciprocalE^{x}-E^{y}mode conversion functions, respectively. Relations between structural parameters are derived by perturbation analysis, and design examples of single-mode isolators with 3.6-, 4.6-, and 6.6-μm square cores are given at the 1.55-μm wavelength. Tolerances in the structural parameter deviations are investigated analytically and numerically. Isolation of more than 20 dB is feasible without any parameter adjustment even when there is a 9- percent deviation in the core dimension.     

带有环形谐振器L型弯折光子晶体波导性能的研究

本文提出了一种带有环形谐振器的L型弯折光子晶体波导结构,利用时域有限差分法研究了该波导电磁波的传输性能.分析结果表明:该结构具有宽频带、高传输率等特点,在光通讯器件制作、光子晶体集成化等方面具有潜在的应用价值.     

Field theoretical CAD of open or aperture matched T-junctioncoupled rectangular waveguide structures

The rigorous computer-aided design of rectangular waveguide structures coupled by open or rectangular iris loaded E- or H-plane T-junctions is described. The design theory is based on the full wave mode-matching method for the key-building-block T-junction element associated with the generalized S-matrix technique for composite structures. The waveguide structures may be arbitrarily composed of the T-junction and already known key-building-block elements (such as the double step and the septum discontinuity) combined with homogeneous waveguide sections between them. The E- or H-plane T-junction effect, large apertures, finite iris or septum thicknesses, and higher-order mode interactions at all step discontinuities are rigorously taken into account. Typical design examples, like rectangular iris coupled T-junctions, narrow-stopband waveguide filters, high return loss E-plane T-junction diplexers, an elliptic function E-plane integrated metal insert filter and a simple ortho-mode transducer demonstrate the efficiency of the method. The theory is verified by measurements     

Radiation from a flanged rectangular waveguide

The radiation from a rectangular waveguide with a perfectly conducting infinite flange is rigorously studied by using the method of the Kobayashi potential (KP). The fields in the waveguide and half-space are expanded in terms of the waveguide modes and the Weber-Schafheitlin discontinuous integrals, respectively. Continuity of the tangential aperture fields yields matrix equations for the expansion coefficients and the matrix elements consist of double infinite integrals and double infinite series of Bessel functions, which are calculated efficiently by applying the asymptotic approximation of the Bessel function. Numerical results are presented for various physical quantities, such as the aperture admittance, reflection coefficient of the incident wave, and magnitudes of higher-order mode waves, as well as the far-radiation pattern and aperture fields. To verify the validity of our method, the results are compared with other methods and excellent agreement is obtained.     

Electromagnetic wave radiation through the gyrotropic semiconductor wall of rectangular waveguide

The peculiarities of the microwave radiation through the semiconductor wall of the rectangular metallic waveguide set in the external magnetic field have been investigated. The radiation direction dependence on wave frequency, the external magnetic field, and the geometric shape of the semiconductor element have been determined. It has been shown that in the case of the wedge-like semiconductor element the radiation direction can be controlled by the external magnetic field. The experiments have been carried out in V-band at the temperature of liquid nitrogen.     

Space harmonic peniotron in a magnetron waveguide resonator

The paper describes both simulated and experimental results observed in high cyclotron harmonic peniotron oscillators with magnetron waveguide resonators and discusses the operation modes of the oscillation. We made the modes clear by considering interactions between an axis encircling electron beam and the space harmonic components of the respective modes generated in the magnetron waveguides. To make it possible to operated at higher frequencies, we introduced a new concept for designing high cyclotron harmonic tubes based on a space harmonic of the 2 π mode interaction. We then presented design parameters for a number of peniotron tubes operable up to 300 GHz with relatively low magnetic field     

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.     

Experimental investigation of the input-impedance characteristics of an antenna in a rectangular waveguide

The input impedance of a monopole antenna in a rectangular waveguide is investigated experimentally. It is found that theoretical results based on the assumption of a sinusoidal current distribution are in good agreement for monopole lengths up to about 0.6 of the guide height and about 1/4 ?0. For longer monopoles, a more accurate theory should be sought.