Analysis and applications of layered multiconductor coupled slot and strip-slot structures.

摘要

Layered multiconductor coupled slot and strip-slot structures are characterized by introducing the full-wave modal analysis as well as the quasi-TEM spectral domain technique. In the modal analysis, the electric and magnetic fields are constructed in terms of modal fields in different regions. Application of the boundary conditions at interfaces for the tangential components of the electric and magnetic fields results in the dyadic Green's function, which interrelates the tangential currents and electric fields at the boundaries of the layered structure. The slot fields and strip currents are expanded in terms of a set of known basis functions with unknown coefficients. Use of the Galerkin method leads to a set of algebraic equations. The non-trivial solutions for the propagation constants are found by setting the determinant of the algebraic equations equal to zero. All the other normal mode parameters including the modal impedances, the field and current eigenvectors are then computed by using the solutions of the propagation constants. In the quasi-TEM analysis, the Laplace equation is transformed to an ordinary differential equation in the spectral domain, the solution of which together with the boundary conditions yields the Green's function which interrelates the potential and the charge distribution at the interfaces of the layered structure. The charge distribution is expanded in terms of known functions with unknown coefficients which are subsequently evaluated by applying the Galerkin method. Once the charge distribution is found, the quasi-TEM characteristics of the coupled strip-slot structures are readily calculated.; Different impedance definitions proposed in the literature for multiple coupled line structures are discussed. The only useful impedance definition in the design of microwave and millimeter-wave circuits is the one that results in a symmetric impedance matrix for a coupled line structure in a lossless, isotropic, and linear medium. The normal mode impedance definition as based on the reciprocity is used to systematically study the impedance characteristics of various coupled slot structures for the first time, which together with the propagation characteristics are used to compute equivalent circuit models for ideal coupled line structures. The applications of the coupled slot and strip-slot structures are illustrated through design examples of enhanced couplers and power dividers consisting of coupled line multiports. Time domain simulation of coupled multiconductor structures with slotted ground planes is also presented to exemplify the applications of the techniques developed in this thesis to layered interconnects and packaging structures in high-speed circuits. Some novel techniques to reduce the crosstalk noise in those structures are proposed with theoretical examples and experimental results.