Micromachined circuits for millimeter- and sub-millimeter-wave applications

Two approaches for the development of micromachined circuits for millimeter- and submillimeter-wave applications are discussed. These technologies provide a means to overcome the drawbacks typically associated with conventional planar transmission lines, such as microstrip and coplanar waveguides. Examples demonstrating the use of micromachining to effectively incorporate a third dimension into the geometry of monolithic circuits are presented. This introduces additional parameters in the design and results in structures with superior electrical performance, such as membrane-supported circuits, and reduced volume and weight, such as micromachined-shielded circuits. Micromachined circuits which incorporate miniaturized shielding packages in a monolithic design are described. The performance of these circuits shows that the low-volume, low-weight packaging is effective in reducing signal loss, without degrading the desired frequency response.<>