A 2-D acoustic array for diagnostic imaging

The fabrication of an acoustic 2-D phased array was investigated. For 3-D imaging at 3.5 MHz an array with 64*64 elements, sizes each 0.22*0.22 mm(2) covering a footprint of 2*2 cm(2) was projected. In our modular construction concept the array will be composed of 32 prefabricated and pretested double line modules with 2*64 elements, including ASIC electronics located in the rear of the modules. An array of 8*64=512 elements was made up of 4 modules. A 64 channel Tx/Rx electronics in SMT was developed and measured together with the modules. Single element two way insertion loss of 42 dB and the broad bandwidth of the acoustic pulse gave proof of the high quality of our design and fabrication processes, even for elements as tiny as a grain of salt.