Loop coupled microwave cavity

A microwave cavity apparatus for use in measuring dielectric characteristics, comprising:

• a cavity, having a cylindrical cross section and closed at both ends, one end having a lock hole;
• and
• a loop coupler, inserted into the lock hole, for impedance transforming and loop coupling, the loop coupler comprising:
• a receiving end for receiving a microwave signal;
• and
• an excitation portion, protruding from the lock hole into the cavity when the loop coupler is inserted into the lock hole, including:
• a loop coupling part, connected to the receiving end, having a bending part being in contact with the inner wall of the cavity;
• wherein the excitation portion transmits the microwave signal and excites the cavity with the microwave signal, and the microwave cavity apparatus is excited in TM012 mode.

A microwave cavity apparatus for use in measuring dielectric characteristics, comprising:

• a cavity, having a cylindrical cross section and closed at both ends, one end having a lock hole;
• and
• a loop coupler, inserted into the lock hole, for impedance transforming and loop coupling, the loop coupler comprising:
• a receiving end for receiving a microwave signal;
• and
• an excitation portion, protruding from the lock hole into the cavity when the loop coupler is inserted into the lock hole, including:
• a loop coupling part, connected to the receiving end, having a bending part being in contact with the inner wall of the cavity;
• wherein the excitation portion transmits the microwave signal and excites the cavity with the microwave signal, and the lock hole is mushroom-shaped.