Microwave resonant cavity for high density telecommunications system - has helicoidal spring behind piston in cylindrical cavity to eliminate parasitic resonance modes and providing electrical coupling

摘要

A cylindrical cavity (10) contains a piston (20) which defines a resonant volume (30) with a particular height (L1) and dia. (D) to permit resonance in the TE011 mode. The piston (20) has parallel faces (21,22) separated by its thickness (e) and is made of conducti material. These faces are parallel to the base (12) and top (13) of the cavity. A gap (23) between the piston and the cavity wall allows the parasitic resonant modes to be eliminated. A helicoidal spring (40) compressed between the back of the piston and the top of the cavity has a cylindrical shape with a dia. slightly less than that of the cavity. The spring is a good conductor and is used to prevent resonance in the TE311 mode.