Abstract: The single toroidal non-reciprocal ferrite phase shifterthat is the key components of a phase array antenna is studied to develop the phase array antenna for autotracking synchronous communication satellite. The transcendental equation for the single toroidal non-reciprocal ferrite phase shifter is obtained by using the twin slab model, and its properties are discussed. The differential phase shift changes as the change in the thickness of the ferrite phase shifter is calculatedwith the transcendental equation. The results showthat the differential phase shift increases with the increase in the thickness of the ferrite slab and the increase becomes gradual when the thickness increases to certain values.