Electrically long vertical interconnects for microwave circuits and antennas

Abstract

As microwave circuit applications proliferate, they are being placed into many new, non-planar configurations. Any circuit using multiple circuit levels requires a vertical interconnect between the planes. Research on this topic has focused on optimizing these interconnects to be low-loss, wide band, lightweight, easy to implement, and cost effective. One specific application uses vertical interconnects between the antenna elements and the T/R modules on a satellite phased-array antenna. This thesis details work performed on four vertical interconnect configurations: the coaxial interconnect, the pin interconnect, the rectangular waveguide interconnect, and the patch interconnect. Electrical specifications called for 20% bandwidth operation at insertion loss less than 1dB and return loss less than 20 dB for the vertical interconnect and two transitions. The analysis, design techniques, and simulation results are presented for each configuration. Measured results are also presented for the coaxial, rectangular waveguide, and patch configurations. Results indicate that the rectangular waveguide interconnect best meets the design specifications. The coaxial interconnect is the second best because it is slightly more difficult to implement.