Dual-layer transducer array for 3-d imaging

The difficulty in fabricating and connecting large numbers of 2-D array elements has limited the development of 2-D transducer array with more than 5000 elements. In this paper, we propose a dual-layer transducer array design which uses perpendicular 1-D arrays for 3-D imaging. This transducer design reduces the complexity of fabrication and the number of channels while maintaining adequate performance compared to a fully sampled 2-D transducer array. To demonstrate feasibility, we constructed a 4cm x 4cm prototype dual-layer transducer array which consists of 256 elements for each layer operating at 4MHz. Both layers used P[VDF-TrFE] material. The -6dB fractional bandwidth was 130% without matching layer. The measured crosstalk of P[VDF-TrFE] layer was -24dB in the frequency range of 3MHz-10MHz. We also verified the performance of this transducer using a wire target phantom. The theoretical beamwidth was 0.62mm compared to the measured beamwidth of 0.53mm using coherence factor when f-number is 1.6.