Novel 3-D Micro-Coaxial Interconnecting Method for THz Monolithic Microwave Integrated Circuits

This paper provides a novel 3-D micro-coaxial interconnecting method for multilayer monolithic microwave integrated circuits (MMICs) using rectangular micro-coaxial transmission lines. Compared to traditional microstrip or coplanar waveguide transmission lines, the rectangular micro-coaxial transmission line offers lower loss, lower weight, higher power capacity and better shielding characteristics. Hence, the rectangular micro-coaxial transmission line is an ideal candidate for signal transmission especially for MMICs in THz range. Moreover, the micro-coaxial transmission line could realize vertical interconnections, replacing high loss via holes. In this paper, a multilayer MMICs system was demonstrated using the proposed 3-D interconnecting method. Finite-element analysis was carried out to compare the electrical performance of the proposed multilayer MMICs with rectangular micro-coaxial transmission lines to that using traditional microstrip and via holes.