Abstract: A sonar unit includes: a circuit substrate on which a transducer, electronic components constituting a circuit configured to drive the transducer, and an input-output terminal for the circuit are mounted; and a shield unit. The shield unit includes a plate portion at a position where the plate portion overlaps at least a part of the electronic components when the shield unit is viewed in a thickness direction of the rectangular circuit substrate. The shield unit includes a window portion provided as a through-hole or a notch. The window portion is placed at a position close to the input-output terminal in a longitudinal direction of the rectangular circuit substrate when the window portion is viewed in the thickness direction of the rectangular circuit substrate.

Abstract: A sonar unit includes: a circuit substrate on which a transducer, electronic components constituting a circuit configured to drive the transducer, and an input-output terminal for the circuit are mounted; and a shield unit. The shield unit includes a plate portion at a position where the plate portion overlaps at least a part of the electronic components when the shield unit is viewed in a thickness direction of the rectangular circuit substrate. The shield unit includes a window portion provided as a through-hole or a notch. The window portion is placed at a position close to the input-output terminal in a longitudinal direction of the rectangular circuit substrate when the window portion is viewed in the thickness direction of the rectangular circuit substrate.