Which term describes the method of shaping the array excitation to suppress sidelobes?

• A. Aperture
• B. Apodization
• C. Array
• D. Channels

Answer: (B)

Apodization is shaping the array excitation with a taper across the elements to control interference patterns. By reducing the excitation of elements toward the edges, the radiated field becomes more uniform in the forward direction and less energetic at angles away from the main beam, which lowers sidelobes and grating lobes. This improves image contrast and reduces off-axis noise, though it slightly broadens the main beam and lowers peak intensity because not all elements are driven at full power. In ultrasound practice, common tapering schemes (windows) like Hann, Hamming, and Blackman are used to implement apodization. The aperture refers to the physical transmitting surface, the array is the configuration of the elements, and channels are the independent paths driving those elements, but sidelobe suppression specifically comes from applying apodization.