Abstract: In order to tailor the ultrasound distributions to deep and sized tumors, a new method of two-frequency signals simultaneously driving phased-array elements is firstly proposed in this paper. Two requirements should be met in method of field conjugation with direct synthesis; One is the use of the pseudo -inverse method to compute element amplitude and phase driving distributions as a constraint condition; the other is the objective function to concentrate the energy to the sites. The paper also illustrates the field patterns of two frequencies driving to the rectangular sources.

Key words: phased-array, field conjugation, optimization, ultrasound