Suspended stripline on magnetized ferrite and anisotropic dielectric substrates

Suspended stripline on magnetized ferrite and anisotropic dielectric substrates are examined here. The spectral domain immittance approach was used for obtaining the dyadic Green's functions in the Fourier transform domain. Galerkin's method was used to obtain the dispersion characteristics of the dominant mode, and the curves for a few cases are shown as examples which could be used in designing isolators, phase shifters, and directional couplers.     

Spectral domain analysis of coupled microstrip lines on magnetized ferrite substrates

Dispersion characteristics of coupled microstrip lines on ferrimagnetic substrates are presented and their features discussed. The Hertz vector potentials in the spectral domain method are used to calculate the dyadic Green's functions in an impedance matrix form. The behavior of the propagation constants is obtained by using the spectral Galerkin's technique. Numerical results are found as a function of various geometrical parameters and of the externally applied static magnetic field. Nonreciprocal behavior is mainly observed when the static magnetic field is applied in the transverse direction, parallel to the ground plane.     

Frequency-dependent characteristics of shielded broadside coupledmicrostrip lines on anisotropic substrates

A spectral-domain technique is applied to compute the propagation characteristics of a shielded broadside coupled microstrip line printed on homogeneous uniaxial and biaxial substrates. The formulation derives the Green's functions for even and odd modes of the guiding structure via the transformed fourth-order differential equations. The analysis includes anisotropic substrates which are simultaneously characterized by both [ϵ] and [μ] tensors. This rigorous full-wave approach to the solution of the problem is shown to yield results agreeing well with the existing data. The propagation characteristics are studied with respect to different line width/thickness ratios as well as to the material substrate parameters     

Characteristics of aperture coupled microstrip antennas on magnetized ferrite substrates

The method of moments in the spectral domain is applied to the full-wave analysis of aperture coupled microstrip antennas in the case where the substrate of the antennas is a layered medium containing magnetized ferrites. The subsectional basis functions used in the analysis make it possible to handle patch antennas and coupling apertures with right angle corners of arbitrary shape. The numerical results obtained show that antennas on ferrite substrates fed by single microstrip lines can radiate both circular and linear polarization, the polarization state being dependent on the orientation of the ferrites bias magnetic field. For a given polarization state, the matching frequency band of the antennas can be tuned over a wide frequency range by adjusting the magnitude of the bias magnetic field. Also, the polarization state can be continuously tuned from circular to linear within the same frequency band by adjusting both the magnitude and the orientation of the bias magnetic field. Some measurements are presented in order to check the validity of the numerical algorithm developed.     

Spectral-domain analysis of shielded microstrip lines on biaxiallyanisotropic substrates

The spectral-domain technique is extended to the study of shielded microstrip lines on biaxial substrates. The analysis simultaneously includes dielectric and magnetic anisotropy effects. A fourth-order formulation leads to the determination of the appropriate Green's function for the structure. The characteristic equation is formed through the application of the Galerkin method to the equations resulting from the boundary conditions on the strip. Numerical results calculated by this method for isotropic as well as dielectrically anisotropic substrates are compared with the existing data, and in both cases a very good agreement is observed. New data on the propagation constant of the shielded microstrip with different substrate permittivities and permeabilities are presented to illustrate the effects of the material parameters on the characteristics of the microstrip line     

The nonlinear study of microstrip lines containing ferrite dielectric layers

In this paper, the transient responses of microstrip containing ferrite dielectric layers are studied by using extended FD-TD method. When the microwave signal propagating along the microstrip is comparable with the applied DC magnetic field on the ferrite, the nonlinearity of ferrite medium is represented. The propagating procedure of Gaussian pulse in the microstrip are simulated. It is shown that the effects of the pulse amplitude on the transmission distortion of Gaussian pulse is pronounced.     

Quasistatic characteristics of microstrip on arbitrary anisotropic substrates

An analytical approach is used to find the upper bounds of microstrip line capacitance which arbitrary anisotropic substrate. General expressions are obtained for the permittivity and the thickness of an equivalent isotropic substrate. The method is used to compute the upper and lower bounds parameters of microstrip on sapphire substrate.     

Dispersion characteristics of open and shielded microstrip linesunder a combined principal axes rotation of electrically andmagnetically anisotropic substrates

This work examines the dispersion properties of microstrip transmission lines whose substrate permittivity and permeability tensors are rotated simultaneously. The analysis takes into account both shielded and open structures, including both single and coupled microstrip line geometries. The spectral-domain method is utilized to formulate the dyadic impedance Green's function, and Galerkin's method is applied to find the propagation constants. Numerical studies are performed when the angular difference between the principal axes of [ϵ] and [μ] tensors is fixed, but both are rotated from 0 to 90°. The dispersion characteristics for all structures are computed over a wide frequency band that ranges from 0.1-100 GHz. The study indicates that propagation properties of microwave integrated circuits (MICs) with dielectrically and magnetically anisotropic substrates (such as composites) can be changed considerably by the misalignment of material and structure coordinates systems     

Finite-element analysis of generalized V- and W-shaped edge andbroadside-edge-coupled shielded microstrip lines on anisotropic medium

This paper presents detailed finite-element analysis of generalized V- and W-shaped shielded microstrip lines in an anisotropic medium. The computed results show detailed quasistatic characteristics of the effective dielectric constant, characteristic impedance, and conductor loss of the lines. The broadside edge coupled lines are proposed for the first time in this paper. Unlike the previous analysis based on the conformal mapping method, this analysis takes into account the top walls and sidewalls, finite metallization thickness, and dielectric anisotropy. The results presented in this paper will considerable advance microwave-integrated-circuit technology using V- and W-shaped shielded microstrip lines     

Characteristics of broadside-coupled microstrip lines with iso/anisotropic substrates

A quasistatic analysis of broadside-coupled microstrip lines using a series form expression of Green's function and the method of moments is described. Characteristic impedances, effective permittivities and ratios between phase velocities for the even and odd modes were obtained for various values of strip widths, W/b, spacings between strips, s/b, and for isotropic and anisotropic substrates.     

Radiation and scattering characteristics of microstrip antennas onnormally biased ferrite substrates

Radiation and scattering characteristics of microstrip antennas and arrays printed on ferrite substrates with a normal magnetic bias field are described. The extra degree of freedom offered by the biased ferrite can be used to obtain a number of novel characteristics, including switchable and tunable circularly polarized radiation from a microstrip antenna having a single feed point, dynamic wide-angle impedance matching for phased arrays of microstrip antennas, and a switchable radar cross section reduction technique for microstrip antennas. Results are obtained from full-wave moment method solutions for single microstrip antennas and infinite arrays of microstrip antennas. A cavity model solution for a circular patch antenna on a biased ferrite substrate is also presented, to aid in understanding the operation of these antennas     

Inverted microstrip and suspended microstrip with anisotropic substrates

This letter presents characteristics of the inverted microstrip and the suspended microstrip, with anisotropic substrates. The transverse transmission-line method combined with the mapping method and the variational technique in the space domain are used to analyze the impedance characteristics. The data presented should find application in the design of MIC components at millimeter-wave frequencies.     

Dispersion characteristics of coupled microstrip with overlay on anisotropic dielectric substrate

The letter describes how one can obtain the equal effective dielectric constants of even and odd modes on the parallel-coupled microstrip at a frequency by using an anisotropic dielectric substrate with isotropic overlay. The frequency can be varied by using overlays of various thicknesses. The results suggest the possibility of realising a high-directivity coupler in the high-frequency microwave range.     

Dispersion characteristics of asymmetric coupled slot lines on dielectric substrates

A modified coplanar waveguiding structure, an asymmetric coupled slot line, on a dielectric substrate is considered. The dispersion characteristics of asymmetric coupled slot lines and asymmetric coplanar waveguides are found in terms of the numerically efficient spectral domain technique.     

Periodically non-uniform coupled microstrip lines on longitudinally-magnetised ferrite

Non-uniform coupled lines, which corrugate periodically not only on the inner edges but also on the inner and outer edges of the conductors, are proposed on longitudinally-magnetised ferrite for the first time. Compared with the conventional parallel ferrite-coupled-line (FCL) section, the corrugated structure can modify the operating frequency for non-reciprocity without changing the physical length of the conventional one. In addition, the simulated performance of a periodically non-uniform FCL section indicates a significant performance improvement of broader bandwidth.     

Frequency-dependent characteristics of thick microstrip lines in lossy multilayered dielectric media

The Spectral Domain Approach (SDA) is used for a rigorous full-wave analysis of thick microstrip lines embedded in lossy multilayered dielectric media. The effects of the conductor thickness on the propagation constant and characteristic impedance are investigated.     

Theory of microstrip lines on artificial periodic substrates

This paper presents the theory of a microstrip line on artificial periodic substrates. A two-stage moment method in conjunction with an array-scanning scheme is proposed for the microstrip characterization. The analytic and numerical methods dealing with the interaction of microstrip components (continuous plane-wave spectrum) with artificial periodic materials (discrete plane-wave spectrum, Floquet modes) are discussed. The method of solution involves two stages of vector integral equations and moment methods. The first integral-equation formulation is to find the Green's function for a planar periodic structure. A spectral-domain moment method is applied to the second vector integral equation to determine the fields or currents on the circuit components and the associated parameters of interest. Guided-wave characteristics of a microstrip line on artificial periodic substrates, including the propagation constant and the characteristic impedance, are investigated. Propagation bandgap of a microstrip line due to periodic elements is characterized. Experiment on a three-layer microstrip-line structure with a periodic mid-layer is conducted to validate the theory     

T.L.M. analysis of the dispersion characteristics of microstrip lines on magnetic substrates using 3-dimensional resonators

The dispersion characteristic for a microstrip line on an isotropic magnetic substrate is calculated by the t.l.m. method. The results indicate how errors obtained using approximate TEM analysis vary with frequency. The results also serve to demonstrate the versatility of the 3-dimensional t.l.m. program.     

Analysis of coupled asymmetric microstrip lines on a ferrite substrate

The dispersion properties of asymmetric coupled microstrip lines filled with ferrite medium magnetised perpendicularly to the substrate surface are analysed by the spectral-domain technique. The dispersion characteristics of the fundamental C- and ?-modes are found as a function of various structural parameters and of biasing magnetic field. New interesting properties of guided modes have been observed.