An ultrasound imaging system and methods thereof are provided. A method includes transmitting a plurality of energy signals coded by a first asymmetric phase element toward an object to be imaged, receiving a plurality of echo signals from the object to be imaged, respectively coding the received signals with a second asymmetric phase element, and reconstructing an image data set with an extended depth of field by decoding the received signals. The ultrasound imaging system includes a transmitter transmitting energy signals coded by a first asymmetric phase element toward an object to be imaged, and a receiver receiving echo signals from the object to be imaged, respectively coding the received signals with a second asymmetric phase element, and reconstructing an image data set with an extended depth of field by decoding the received signals.