2017-08-15

• It appears to me that the major factor limiting the improvement of the modes that either remain equal or diminish is that the original design was already quite good at exciting those modes. As can be seen in the attached plots, the original design is about as well centered over the 5 modes as a rectangle on the x axis can be. As a result, maintaing a constant potential on the ESD it would be difficult to improve the coupled force without specifically tailoring the force profile to a certain mode.
• In order from left to right, the frequencies of the given modes are 14.2 kHz, 16.2 kHz, 16.3 kHz, 23.8 kHz, and 27.4 kHz.