One-channel time reversal focusing of ultra-high frequency acoustic waves on a MEMS

This Letter reports on a work performed to fabricate and characterize a silicon micro-machined cavity dedicated to micro-resolution Ultra-High Frequency imaging in microfluidics and microbiological applications using one-channel time reversal. Time reversal provides the means to spatially and temporally localize elastic energy on a receiver. Here, the arrays of zinc oxide micro transducers are coupled with a 400 mu m thick silicon wafer containing micromachined structures for acoustical field confinement. Characterization of the diffused acoustic field and time-reversal retro-focusing are reported. The transducers are wideband in the 0.2-2 GHz range with a central frequency of 0.9 GHz.

Automated summary

This Letter reports the fabrication and characterization of a silicon micro-machined cavity designed for micro-resolution Ultra-High Frequency imaging in microfluidics and microbiological applications using one-channel time reversal. The wideband zinc oxide micro transducers coupled with the silicon wafer enable acoustical field confinement, and the diffused acoustic field and time-reversal retro-focusing were characterized. The transducers have a frequency range of 0.2-2 GHz with a central frequency of 0.9 GHz.