PCB-Based Prototyping of 3-D Micromachined RF Subsystems

A stacked printed circuit board (PCB) approach for prototyping 3-D microfabrication enabled millimeter and submillimeter wave components and subsystems is proposed. To demonstrate this approach, a 4 to 8 GHz two element tapered slot antenna array with integrated rectangular coaxial 90 ° hybrid, and its stand-alone elements, are designed and fabricated. Measured subsystem results show properly formed radiation patterns, realized gain from 9 to 11 dBi, and 3-dB beamwidth from 30 ° to 45 °. Excellent agreement between simulations and measurements of individual components and the full subsystem as well as outcomes of a tolerance study and comparison to a Ka band micromachined subsystem confirm suitability of the proposed approach for fast, low-cost prototyping of 3-D micromachined rectangular coaxial components and subsystems.