Two-coupled Lines Research Articles

Nonlinear Large Deflection of Thin Film Overhung on Compliant Substrate Using Shaft-Loaded Blister Test

This paper presents the nonlinear large deflection of the thin film and the effect of substrate deformation on the thin film deflection through the shaft-loaded blister test. The blister of thin film can be divided into two parts, namely, the annular contact brim and the central noncontact bulge. A two-coupled line spring model is developed to describe the deformation of the contact part, and Föppl–Hencky equations are employed to study the constitutive relation between the applied load and the central deflection. The analytical and numerical solutions for the constitutive relation between the applied load and the deflection of thin film with considering the deformation of substrate are derived.

Reduced-Length Two-Section Directional Couplers Designed as Coupled-Line Sections Connected With the Use of Uncoupled Lines

Broadband coupled-line directional couplers having the properties of two-section coupled-line directional couplers are proposed. The presented couplers are composed of two-coupled line sections having the same coupling coefficient which are connected with the use of two sections of uncoupled transmission lines. It is shown that in such a structure it is possible to achieve an equal-ripple coupling characteristic similar to the coupling response of classic-two section coupled-line couplers. It is also shown that, in comparison to the classic counterparts, in the proposed couplers the required coupling between the coupled-lines is slightly weaker and the overall electrical length is reduced. The theoretical analysis and measurement results of a 3 dB directional coupler operating at a center frequency of 1.8 GHz are presented.

On the Analysis and Design of Spurline Bandstop Filters

The parameters of general two-coupled lines and symmetric three-coupled lines in an inhomogeneous medium for the lossless case are obtained. The impedance and chain matrices of spurline bandstop filters are derived. One-section spurline bandstop filters with their stopbands centered near 33 GHz have been designed and tested. There is excellent agreement between the experimental results and those predicted theoretically.