Optimum receive apodization for photoacoustic imaging using a CMUT

Capacitive micromachined ultrasound transducers (CMUTs) are gaining more interest for photoacoustic imaging due to its low-cost, high bandwidth and flexibility in size and shape. However, the beampattern of CMUTs usually exhibits wide mainlobes and high sidelobes, degrading the imaging resolution and contrast. We propose to improve the beampattern with optimization of apodization by imposing conditions on the angular distribution of the signal energy received from a PA point source to minimize the sidelobes magnitude and maintain the mainlobe energy. Both simulations and experiments results demonstrate that the proposed apodization suppress the sidelobes up to 30dB when compared with Uniform weights.