startrekfreedom.com/wiki/index.php/De…
The basic principle of regenerative shielding was to quickly analyze an attacking weapon's frequency and then modulate shield freqency to increase damage mitigation without depleting shield energy.

Regenerative shields were used on Borg vessels and Borg drones. When in combat, Borg drones could be killed by phasers but only for the first several shots. The phaser became ineffective if used at the same setting after multiple shots. The phaser's effectiveness could be extended though by adding a frequency modulation chip. (TNG: "Q Who", "The Best of Both Worlds", "The Best of Both Worlds, Part II") However, Borg drone shields appeared to be less resilient to projectile weapons; when the Borg attempted to assimilate the USS Enterprise-E in 2063, Jean-Luc Picard lured two drones into the holodeck and used a holographic Thompson submachine gun to kill the two drones. (Star Trek: First Contact)

Starships from other races equipped with this type of shielding included sensors integrated within the shield systems' own energy that alters the frequency to better protect the ship.

The battle systems of Starfleet's Prometheus-class starships included regenerative shielding, ablative armor, and multi-vector assault mode. (VOY: "Message in a Bottle")

sto.gamepedia.com/Regenerative_Shield…
The Regenerative Shield Array is a type of Ship Shields that has a 10% lower maximum capacity but a 25% faster regeneration than the standard [Shield Array].

16thfleet.wikidot.com/defensive-systems
Regenerative Shielding is an enhanced energy shield capable of regenerating after taking damage.

The regenerative shield array is the opposite of the covariant. This shield array has the lowest capacity and the highest regeneration rate. It has a 10% lower capacity than a standard shield array but 25% more regeneration. I find that these shields are very effective on fast turning ships with high defense ratings, such as escorts, raiders and some of the agile science ships. If your ship has a high defense rating the enemies will not land as many hits and thus your shields will last longer. The agile ships also can quickly turn away from the source of the damage by rotating shield facings that are taking damage and thus effectively increasing capacity with the rotation technique. The faster regeneration rate means that the shields depleted facings will come back faster so they will be ready by the time the ship comes back around. The idea here is that a fast turning ship can “hide” a depleted shield facing by quickly turning the ship away from the source of damage and exposing a fresh shield facing to the enemy. Slow turning ships can not pull this off as they are too slow on the corner. Also, this technique is ineffective when you have managed to fly into a shit storm and are taking damage on all sides. The regenerative shield is easier to deplete with shield draining technology due to the low capacity. If you are the type of captain that likes to fly into danger with reckless abandon, and you tend to generate a lot of threat, these may not be the shields for you.