Abstract: In this paper, relationship between focusing gain of focused liquid-filled sphere vs frequency in different width of pulse was studied. Formula of outstanding focusing gain difference was deduced. The change of focusing gain of long pulse vs frequency is described with this formula. Corresponding experiment was made. Its results explain that the change of focusing gain of short pulse with frequency is small. Frequency property of focusing gain of long pulse relate to size of focusing gain of short pulse. Experimental results are in good agreement with theoretical results. In order to obtain big target strength and better frequency property must great as much as possible focusing gain of short pulse.
Experiment of focusing gain vs wall thick of sphere was made too. Experimental results explain that wall thick of sphere clearly effects focusing gain of focused liquid-filled sphere and its frequency property.