Multilayer asymmetric aperture-coupled broadside microstrip lines and their quasi-static and dynamic analyses

This paper describes new multilayer aperture-coupled broadside microstrip lines suitable for miniaturized microwave and millimeter-wave integrated circuits. Spectral-domain method is used for detailed investigations of these structures, and both quasi-static and dynamic results are presented to illustrate the need of a full-wave analysis for accurate circuit designs at high frequencies. The new transmission lines possess many desirable features, such as flexibility in circuit design and ability to optimize various transmission lines´ characteristics, as well as miniaturization by using thin dielectric layers. Besides having the inherent properties of large ratios for the mode characteristic impedances and effective dielectric constants found in broadside-coupled structures, we also found that the studied coupled transmission lines can have equal mode effective dielectric constants for certain values of the structural parameters