Extended method of line procedure for the analysis of microwave components with bianisotropic inhomogeneous media

Method of line (MoL) procedure is very useful in the analysis of radiative and transmissive microwave components, but its standard version does not allow for the study of elements with complex substrates. In this work, we first show that components integrated into materials exhibiting the magneto-electric effect (biisotropic and general bianisotropic media) cannot be analyzed following a standard MoL algorithm. Next, we derive an extended MoL numerical tool, which allows for the analysis of components in the presence of any linear medium (even inhomogeneous, bianisotropic and lossy). Such an extension is based on the generalization of the transmission-line equations for a general linear medium, which, in the case in point, are not necessarily decoupled. Furthermore, we present the full coincidence of this new method with the standard MoL in the case of simpler media (i.e., not exhibiting the magneto-electric effect) and, finally, we show some numerical results, obtained analyzing microwave antennas and resonators with bianisotropic and chiral substrates.     

New equivalent circuits for inhomogeneous coupled lines withsynthesis applications

Equivalent circuits for inhomogeneous coupled-line sections are presented which enable cascade synthesis procedure to be applied to the design of very-broadband inhomogeneous filters. Here, the term inhomogeneous means that the even and odd modes have different phase velocities and different electrical lengths. The method has been implemented in the design of inhomogeneous high-pass filters constructed in suspended substrate stripline, when the even-mode characteristic impedance is much greater than the odd-mode characteristic impedance. An approximate but highly accurate synthesis of a 3:1 bandwidth-inhomogeneous distributed high-pass filter is described. The procedure is almost purely analytic, and computer-aided design is required only for fine tuning adjustments. The theoretical feasibility of designing such filters for upper-pass bandwidths of greater than 8:1 is demonstrated     

Generalized coupled azimuthal potentials for electromagnetic fieldsin inhomogeneous media

The original coupled azimuthal potential (CAP) formulation utilized two continuous potentials to represent the Fourier azimuthal modes of the vector field components in inhomogeneous axisymmetric material media. This formulation has since been used as the basis for finite-element solutions of radiation, scattering, and penetration problems. A generalization of the CAP formulation is presented that removes the restriction to axisymmetry of the inhomogeneous media while retaining the advantage of vector field generation in terms of only two scalar potentials. The discrete form of this generating relation is cast into a matrix transport equation, which is solved by the use of natural basis function. Variational and Galerkin approaches are considered for the solution of the given potentials. Computational examples, using finite elements, are given for the case of a simple three-dimensional boundary-value problem     

Characteristics of inhomogeneous coupled cylindrical striplines

The letter presents a method for the determination of even and odd mode impedances of inhomogeneous coupled cylindrical striplines using the conformal mapping technique. Closed-form expressions for characteristic impedances are obtained. The analysis can also be extended to coupled cylindrical microstrip lines and warped coupled strip and microstrip lines.     

Asymmetric coupled lines in an inhomogeneous medium

Up-to-date, asymmetric coupled lines in an inhomogeneous medium have been dealt with either theoretically or by making use of certain properties obtained in practice. According to certain formulas, these properties are only valid for extremely special geometrical configurations. However, we realised from the general theory, by performing numerical applications, that these properties possess an unexpected application domain: they are, in particular, valid for practically all experimental manipulations.     

The first-order coupled differential equations for waves in inhomogeneous warm magnetoplasmas

The first-order coupled differential equation for waves in gyrotropic inhomogeneous warm magnetoplasmas are derived for the case where the plasma parameters N0(z), T0(z), v(z), and H0(z) vary in the z direction only. In this form they are well sited for solution on a digital computer by the Runge-Kutta method.     

Design of aperture coupled microstrip antenna array fed bydielectric image line

A novel design for a linear array of microstrip antennas, aperture coupled to a dielectric image line has been developed. The design is based on a simplified theory to determine the impedances of the antennas at their apertures, and in turn, the coupling to each antenna from the image line. The theory developed is verified using an eight-element linear array and the experiment results are very good     

A flexible synthesis procedure for line source antennas

A technique is described for the synthesis of line source antennas. This technique provides arbitrary control of individual extrema of the radiation pattern. It may be used to apply independent specifications to individual sidelobes or to specify certain types of shaped beam patterns. Independent control is also provided for the asymptotic behavior of the more remote sidelobes.     

Lumped element networks for replacing sections of a buriedtransmission line

A buried transmission line formed by vertical conductors can function as a wave guiding structure in producing a part of the electromagnetic field distribution caused by a distributed source at the air-earth interface. Such a structure, when excited by an appropriate low-frequency source, is a viable EMP simulation technique for use with underground systems. In the developmental phase of such a technology, there exists a need to artificially elongate the buried line by using lumped element networks. In effect, such networks simulate the simulator plates and earth. The authors address such a network concept and its design considerations. The actual design, fabrication, and testing of an example network are also presented     

Transient response of an inhomogeneous MOS transmission line

Analytical solutions for charge transport in inhomogeneous MOS transmission lines are obtained. The line is assumed to have an initial exponential doping profile. An exact solution is obtained for the case of a constant charge being injected into the structure. An approximate solution is obtained for the case of a fixed voltage being applied at one end of the structure.     

A procedure for designing EMI filters for AC line applications

A procedure for designing AC power line EMI filters is presented. This procedure is based on the analysis of conducted EMI problems and the use of a noise separator. Design examples are given, and results are experimentally verified     

A capacitively coupled meander line for solid-state traveling-wave amplification

A slow-wave structure intended for use in solid-state traveling-wave amplifiers is described. The structure is a meander line with adjacent conducting elements electrically connected by lumped capacitors. The dispersion curve is derived and shown to agree with experiment. The structure is found to have a passband which is dependent on the coupling capacitors. The interaction impedance is estimated.     

An enhanced transmission line model for conductors with arbitrary cross sections

An enhanced transmission line model (ETL) has been recently proposed to describe the propagation along two parallel wires with circular cross sections up to wavelengths comparable to the distance between the wires. In this paper, a general ETL model is proposed to describe the propagation along interconnects consisting of wires with arbitrary cross sections. Since the ETL model has the same simplicity of the standard transmission line model, it allows investigating high-frequency effects, like radiation and dispersion, with a computational cost which is sensibly lower than that required by a full-wave numerical simulation. The ETL model is obtained, with suitable approximations, starting from a full-wave analysis of the propagation problem and using an integral formulation based on the electromagnetic potentials satisfying the Lorentz gauge. Some case studies are carried out and discussed, including a benchmark test with existing literature, performed to check the validity and accuracy of the proposed model.     

Tapered stripline embedded in inhomogeneous media as microwavematching line

A novel design method for a stripline microwave matching line is developed in this paper. Striplines considered have a tapered inner conductor embedded in an inhomogeneous dielectric material with continuous spatial variation of the relative permittivity. The employment of this kind of waveguide, as it is shown in this paper, ensures good matching properties in a wide frequency range. These matching properties can be controlled by means of two different factors: the taper of the stripline inner conductor and the relative permittivity spatial variation of the dielectric material filling the stripline. Starting from the nonuniform transmission-line theory, a novel closed analytical form for the input reflection coefficient of such lines is derived, and design formulas for the matching line are carried out. Finally, several applications that show the capability, flexibility, and fastness of the developed synthesis method are presented     

Self-biased hexagonal ferrite coupled line circulators

The simulated performance for novel hexagonal FCL circulators is presented for the first time. Compared to conventional FCL circulators, these structures do not require external biasing and have the advantages of smaller size and lower conductor and dielectric loss. Simulations show that the size decreases as the value of 4/spl pi/M/sub eff/ of the hexaferrite increases.     

Characterization of V-groove coupled microshield line

A new membrane supported air-filled V-groove coupled microshield has been investigated using finite element method. The even- and odd-mode characteristic impedances and the effective dielectric constants have been computed. The dependence on various dimensions has been studied. The crosstalk levels between adjacent lines have been compared with that in coupled microstrip lines, coupled microstrip lines with lateral ground planes, and V-groove structures with and without metallization in the groove.     

Design of electronic sections for nano-displacement measuring system

Noncontact displacement measurement is generally based on the interferometry method.In the semiconductor industry,a technique for measuring small features is required as circuit integration becomes denser and the wafer size becomes larger.An interferometric system known as a three-longitudinal-mode heterodyne interferometer (TLMI) is made of two main parts:optical setup and electronic sections.In the optical part,the base and measurement signals having 500-MHz frequency are produced,resulting from interfering three longitudinal modes.The secondary beat frequency to measure the displacement in the TLMI is about 300kHz.To extract the secondary beat frequency,wide-band amplifiers,double-balanced mixers (DBMs),band-pass filters (BPFs),and low-pass filters (LPFs) are used.In this paper,we design the integrated circuit of a super-heterodyne interferometer with total gain of 56.9dB in size of 1030μm×1030μm.     

Ring-resonator method - effective procedure for investigation of microstrip line

In addition to the traditional application of the ring-resonator method for determination of the microstrip line effective permittivity, measurements of the insertion losses and equivalent substrate permittivity are proposed. The obtained data for a number of isotropic and anisotropic substrate materials are in good agreement with the results predicted theoretically.     

A lower bound for the length of nonuniform transmission line matching sections

A lower bound for the length of a nonuniform transmission line section needed to match a given load impedance to a given real input impedance is derived. The bound depends not only on the load and input impedances, but also on the maximum and minimum permissible values of characteristic impedance within the nonuniform line. Several specific cases are presented to illustrate the tightness of the bounds.