A generalized theory of tapered transmission line matching transformers and asymmetric couplers supporting non-TEM modes

Personal computer-based direct synthesis of optimum rectangular waveguide E-, H-, and EH-plane transformers

“…Twenty modes were considered for the H-plane transformer. For the EH-plane transformers, only the seven most w x dominant modes were considered 15 : TE , 10 TE , TE , TE , TE , TM , and TM . The developed mode-matching subroutines were verified for accuracy by comparing the computed results for a 100-step transformer with experimental results of a linear smooth taper and its w x cascaded ABCD matrix analysis 13 .…”

“…Because the Ž . width a z of the taper remains constant throughout the length of the taper, the propagation constant of the dominant TE mode as well as all 10 Ž . TE n s 1, 2, .…”

Effect of substrate height variations on radiation properties of microstrip patch antennas on ferrite

“…A smooth linear variation of the substrate thickness that supports the patch is considered to improve the antenna bandwidth [8 -10]. In this context, many works have been devoted to the study of tapered microstrip structures printed on dielectric [11][12][13][14] and ferrimagnetic substrates [15].…”

A general perturbational approach for synthesizing the Riccati‐type nonuniform transmission lines with arbitrarily specified reflection properties

“…A review of them reveals that the treatment of the solutions of nonlinear differential equations such as the Riccati equation, Zakharov-Shabat equation, and Sturm-Liouville equation for reflected spectra has received intense attention. Since the solutions are expressed by an integral equation such as the Riccatitype [1][2][3], the Gel'fand-Levitan-Marchenko-type [4,5] and Volterra-type [6,7], the efficient inverse transform is crucial to recovering a distributed potential corresponding to a transition profile from the given reflected spectra data. Generally, the analytical solution of the potential is not easy to find, especially in inhomogeneous media.…”

“…Generally, the analytical solution of the potential is not easy to find, especially in inhomogeneous media. So the previous numerical inverse transform methods have required a step-by-step segmentation process [1,2] for the regular small reflection responses, the successive approximation [4,7], and/or the overall optimization routines for fitting to the objective reflection spectra window [3,5]. Furthermore, the synthesis of nonuniform coupled-line couplers or filters has required a special iterative method of deducing the continuously varying coupling coefficient, which is parameterized for specified passband with allowed coupling ripples and then optimized [3,8].…”