Every antenna is polarized to propagate its RF signal along a determined plane and for full efficiency, the receiving antenna should be oriented to the same polarization as the transmitter. The two most common types of polarization are vertical, think a serpent moving up and down through water to move, and horizontal, think a snake slithering back and forth on the ground. A 'High-density' or dual-polarized antenna utilizing both polarizations can propagate RF signal along both planes simultaneously. In high density deployments with many clients, having dual polarity dramatically reduces noise and other interference and improves the overall health of your network.