Acoustics: Sound Fields, Transducers and Vibration, 2nd Edition

13.17. Radiation from a rigid rectangular piston in an infinite baffle [39,40]

Far-field pressure

Using the product theorem given in Section 13.16, the directivity pattern is equal to the product of the directivity patterns for two line arrays at right angles to each other [see Eq. (4.89)]. The directivity pattern for this type of radiating source with dimensions l _x and l _y is given by the formula

D ( θ x , θ y ) = sin ( 1 2 k l x sin θ x ) 1 2 k l x sin θ x · sin ( 1 2 k l y sin θ y ) 1 2 k l y sin θ y ,

(13.318)

where θ _x is the angle between the normal to ...