High Frequency Dielectric Spectroscopy Array with Code Division Multiplexing for Biological Imaging

Radio frequency dielectric spectroscopy is an attractive paradigm for low-cost non-optical imaging of cells and bioparticles. While traditional electrochemical impedance spectroscopy is often performed at lower frequencies, working at radio frequencies can overcome ion screening effects and detect features farther from electrode surfaces. We designed and fabricated a 64×64 sensing array with 10 μm pixels in 180-nm CMOS, supporting switching frequencies up to 100 MHz. The array features code-division multiplexed readout of all 64 rows simultaneously, which offers opportunities for extended integration times, higher frame rates, improved common-mode rejection, and new wide-bandwidth sensing modalities.