Co-layered integration and interconnect of planar circuits and nonradiative dielectric (NRD) waveguide

• Published in: IEEE transactions on microwave theory and techniques Vol. 48; no. 4; pp. 519 - 524
• Main Authors: Tang, J., Wu, K.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2000; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Baluns; Circuits; Construction; Coplanar waveguides; Design engineering; Dielectrics; Etching; Frequency; Ground plane; Integrated circuit interconnections; Microstrip; Microwaves; Millimeter wave circuits; Millimeter wave measurements; Millimeter wave technology; Planar waveguides; Waveguides
• ISSN: 0018-9480; 1557-9670
• DOI: 10.1109/22.842022

A concept of hybrid integration between planar circuits and a nonradiative dielectric (NRD) waveguide is proposed in this paper with preliminary experiments. This approach utilizes co-layered arrangement of the two dissimilar structures, which allows the NRD-guide in direct contact with (or surface mounted on) the planar circuits. Two basic building-block schemes are presented that involve microstrip line and coplanar waveguide (CPW) with the NRD-guide. The first is to deposit the NRD-guide on the top of a relatively thin microstrip substrate, thus forming unbalanced NRD-guiding hybrid circuits, while the second is to design CPW circuits directly etched on the ground planes of the NRD-guide. The unbalanced NRD-guide is subject to a certain leakage loss, but at a negligible level, and it may even be suppressed completely in certain circumstances. Such an integration technique is found consistent with the concept of low loss interconnects at millimeter-wave frequencies. In other words, the NRD-guide can be used for viable interconnects of co-layered planar circuits with a simple "put and cover" procedure. Measured results of several co-layered hybrid transitions/baluns indicate that satisfactory transmission properties can readily be achieved. The new building blocks are expected to provide an alternative design approach to three-dimensional multilayered millimeter-wave circuits and systems.