A realization of convenient structure with electrical coupling in coaxial cavity

Electrical coupling is essential in some RF circuits. In this paper, we present a convenient mixed-coupling structure between coaxial cavities, and the ratio of electric coupling coefficient to magnetic coupling coefficient could be tuned easily. As a result, an electric coupling effect without the probe can be achieved in coupling coaxial resonators. For validating the theory, the electric coupling structure is used to realize a four-order cross-coupled filter, and the measured results match well with the theoretical prediction. Especially, there are three transmission zeros near the pass band.