Millimeter-Wave Quasi-Optical MEMS Steered MMIC Amplifier Array

摘要

The development of a 44 GHz MEMS-steered solid-state amplifier array with 100 active elements has been studied. The array has a layered geometry with 10 layers of microstrip circuitry, each containing 10 amplifier/MEMS phase shifter elements configured in parallel as a power combining microstrip/parallel plate waveguide combiner. The final strategy for the grating array and layer array amplifiers was implemented and tested. This involved the construction of a compact array amplifier with a beam launcher consisting of an h-plane sectoral horn with an anti-reflection lens. For loss and reflection optimization, several step geometries were studied for the transition to parallel plate. A split transition scheme was introduced for the transition between parallel plate and microstrip. The MEMS phase shifter fabrication process was studied in more detail to expand the total phase shifting range. Severe reliability issues were encountered, especially in terms of DC isolation of the top metal layer. Different techniques have been used to alleviate this problem, which included using different release methods and the use of a wet metal etch. Additionally, a new process for obtaining more compliant MEMS springs without affecting transmission line parameters was successfully developed, therefore allowing actuation of our phase shifters at lower operating voltages.