Imperial I-class and Imperial II-class Star Destroyers each carried two ISD-72x generators/sensor arrays. The shield projector vanes were positioned in a crown formation around the command tower’s sensor globes. The vanes projected both ray and particle shields and were scattered along the “crown”, one function per vane.
This deflector shield required a massive amount of energy, drawn from the Star Destroyer’s main reactor via power generators located deep within the command tower. Thick armor protected the sensor banks from impacts, but the globes were vulnerable to suicide attacks from small starships or missile weapons such as concussion missiles or proton torpedoes from starfighters.