Micromechanical tuning elements in a 620-GHz monolithic integrated circuit

While monolithic integrated-circuit technology promises a practical means f or realizing reliable reproducible planar millimeter and submillimeter-wave circuits, conventional planar circuits do not allow for critical post-fabr ication optimization of performance. A 620-GHz quasi-optical monolithic det ector circuit is used here to demonstrate the performance of two integrated micromechanical planar tuning elements. This is the first reported demonst ration of integrated micromechanical tuning at submillimeter wavelengths. T he tuning elements, called sliding planar backshorts (SPB's), are used to a djust the electrical length of planar transmission-line tuning stubs to var y the power delivered between a substrate-lens coupled planar antenna and a thin-film bismuth detector over a range of nearly 15 dB, The circuit perfo rmance agrees with theoretical calculations and microwave measurements of a -0.06-dB reflection coefficient made for a scale model of the integrated t uners. The demonstrated tuning range for the SPB tuners indicates that they can be valuable for characterizing components in developmental circuits an d for optimizing the in-use performance of various millimeter and submillim eter-wave integrated circuits.