A microwave filter and method for remotely tuning a microwave filter from
one sub-band to another sub-band using metallic rings to adjust the
capacitance or inductance of the resonator. In adjusting the capacitance,
a plurality of metallic rings are disposed in the upper section or end of
the resonator. Each ring has an RF switch that connects or disconnects
each ring to ground, thereby varying the capacitance of the resonator. In
adjusting the inductance, a plurality of metallic rings are disposed
perpendicular to the magnetic field of the resonator. Each ring has an RF
switch disposed within the electrical path of the ring that opens or
closes the electrical path of each ring. By opening and closing each
ring, the magnetic field of the resonator is altered, thereby varying the
inductance of the resonator.