Flip-Chip Distributed MEMS Transmission Lines (DMTLs) for Biosensing Applications

Design and characterization of a flip-chip distributed MEMS transmission line (DMTL) are presented. The concept of using this DMTL as a biosensor is then introduced. Radio frequency experiments on the DMTL loaded with ldquobiosamplesrdquo have been conducted using the most accessible materials, namely, deionized water and aqueous solutions of salts. Results show that the reflection coefficient (S
₁₁
) of the solution-loaded DMTL is very sensitive to the salt concentration of the solution in the low-frequency ranges of 10 MHz-1 GHz and 3-4.5 GHz. At high frequencies, the relative dielectric constant of the biosample can also be quantitatively determined from the impedance of the DMTL.