Resonant micromachined biochemical sensor

A system for sensing one or more target chemical compounds, comprising:

• an array of one or more resonant sensors each comprising:
• a mechanical spring-mass system employing:
• a thin planar structure lying in a plane and having a damped natural frequency and comprising:
• a motional mass comprising two motional masses spaced apart and dynamically linearly balanced along an X-axis in the plane, wherein two or more spring suspension elements extend in a Y-axis in the plane from the masses to a surrounding frame, the spring suspension elements having a cross-sectional geometry that results in substantially higher stiffness to out of plane motion than X-axis motion to constrain the masses to substantially linear resonant motion in the plane of the thin planar structure while minimizing motion out of the plane;
• and
• an active coating on or in the motional mass with an affinity to capturing or reacting with the target chemical compound in order to change its own mass in response to the presence of the target chemical compound and affect a change in the damped natural frequency of the thin planar structure;
• a linkage constraining the two dynamically-balanced motional masses to move 180 degrees out of phase with each other along the X-axis and substantially constraining both masses from moving side-to-side together, wherein the linkage comprises flexible beams that connect both to the frame and to each motional mass, and wherein the flexible beams define an elongated diamond shape having a first pair of opposite apexes connected to the motional masses along the X-axis and a second pair of opposite apexes connected to the frame and spaced apart farther than the first pair;
• drive electronics to control the amplitude of the driven resonant mode of each sensor in the array at its damped natural frequency;
• an electromagnetic drive and velocity sensor comprising one or more conductive traces across the motional mass oriented substantially orthogonal to a driven resonant motion;
• a magnetic field substantially orthogonal to the one or more conductive traces and a vector of resonant motion to provide drive force to sustain resonant amplitude by running current through each conductive trace, and
• one or more separate conductive traces on the motional mass that are substantially orthogonal to the vector of resonant motion to measure back EMF signals for velocity detection.