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In this paper, some new types of artificial transmission lines, compatible with monolithic-microwave integrated-circuit/miniature hybrid-microwave integrated-circuit technology are presented. In the new designs, short subsections of different lines are connected together to achieve the needed performance of various transmission-line functions such as impedance transformation, power coupling, etc. Theoretical calculations are given and some typical design data are provided, including models of extremely low impedance lines, which are very practical in the design of microwave power amplifiers and oscillators using heterojunction bipolar transistors or high electron-mobility transistors. Calculation results are validated by simulations and experiments. The proposed structures are very flexible and can easily provide transmission lines with widely varying characteristics. Index Terms - Coplanar waveguides, microstrip, microwave integrated circuits, MMIC's, transmission lines.

In this paper, a new structure of tightly coupled lines compatible with monolithic-microwave integrated-circuit/minature hybrid-microwave integrated-circuit (MMIC/MHMIC) technology is introduced. Different from previous designs, short subsections of two or more different coupled lines are alternatively connected together to achieve the needed performance of a single-section coupler or phase shifter. Theoretical calculations are given and some typical design data are provided. A design example of a wide-band coplanar-waveguide (CPW) quadrature coupler using standard MMIC foundry technology is provided. Only metal-insulator-metal (MIM) capacitors and air-bridges are used to achieve tight coupling - no via holes are necessary. Experimental results are in good agreement with simulations. The proposed structure of coupled lines is very flexible and easily achieves very tight coupling factors. Index Terms - Coplanar waveguides, coupled transmission lines, couplers, microwave integrated circuits, MMIC's.

A simple recursive algorithm is presented based on the method of lines for the analysis of multilayered multiple microstrip lines or slots. Our previously proposed scheme of vertical multi-subregion space discretization [1] is used to enhance the numerical accuracy. The recursive formulation is extended to model composite substrates which is aimed at reducing the unwanted coupling among different lines in M(H)MIC's and high-speed interconnects. Numerical results are shown for both quasistatic and hybrid-mode analyses. Results of multiple strips on a composite uniaxial anisotropic substrate are also presented.

In this paper, coupled-mode equations for general bi-anisotropic waveguides with perfect electrically conducting (PEC) walls are studied and a set of rigorous expressions is obtained. The features of these equations are discussed and applications to circular/rectangular Faraday chiral and chiral waveguides are demonstrated. Comparisons between Faraday chiral, chiral, and ferrite-filled waveguides are also given.

A quasi-planar structure called Channelized Coplanar Waveguide (CCPW) is proposed for wideband applications of integrated microwave and millimeter-wave circuits. Compared with the conventional coplanar waveguides, the novel transmission line has a narrow metallic notch channel located underneath the main guiding part, which is able to provide direct grounding equalization without resorting to via-holes or the use of air-bridges. In addition, an electrically shielding condition, based on the theoretical principle of the nonradiative dielectric waveguide, is proposed to suppress radiation losses and reduce leaky-wave propagation in conjunction with the umbilical channel. Some interesting phenomenons regarding the electrically shielding condition are experimentally observed. One attractive feature of the proposed CCPW is its ability to drive higher-order modes towards higher frequency range, and therefore demonstrates a potential for wideband applications. A method of lines with vertical discretization scheme is used to accurately determine dispersion characteristics of the proposed CCPW and influence on mode propagation includin higher-order modes. Theoretical results of dispersion are verified experimentally over large frequency band of interest.

A method-of-lines based technique is presented for efficiently analyzing propagation problems of planar integrated circuits. A scheme of vertical multi-subregion space discretization is used to enhance numerical accuracy by improving most of the edge singularity on metallic conductors. On the other hand, this proposed approach is able to not only handle very narrow strips/very large slots topology or vice-versa, but also simulate exactly bilaterally unbounded structures with possible segmented multilayers. Numerical results including convergence characteristics are demonstrated for both quasi-static and hybrid-mode analysis. Comparison with other publications validates this novel algorithm.