Methods and devices for accelerating or delaying an electromagnetic signal. A rectangular waveguide phase shifter has a ferrite filled center section with a pair of magnetic bias lines placed on opposing sides of the waveguide, each bias line being adjacent to one of the two opposing sides. Each magnetic bias line creates a magnetic field in the ferrite filled center section. The resulting magnetic field in half of the center section has the same magnitude but is oppositely directed to the magnetic field in the other half of the center section. This ideally results in a zero magnetic field at the very center of the ferrite filled center section. A microwave signal propagates through the waveguide phase shifter in a direction perpendicular to the magnetic field lines. The amount of phase shift provided depends on the magnitude of the magnetic fields. These magnetic fields are controllable by adjusting the current passing through the bias lines.