CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 108148613 filed in Taiwan, R.O.C. on Dec. 31, 2019, the entire contents of which are hereby incorporated by reference.

BACKGROUND

In a circuit structure, a substrate integrated waveguide or a microstrip may be used for transmitting electromagnetic wave signals. The substrate integrated waveguide is a kind of waveguide which transmits the electromagnetic wave signals inside a substrate. The microstrip is a kind of transmitting line which transmits the electromagnetic wave signals with a conductive line on a ground layer. Compared to the microstrip, due to the usage of transmitting higher power signals, the substrate integrated waveguide enjoys less transmission loss, and less interference between the substrate integrated waveguide and external noises is observed.

When the substrate integrated waveguide is used for transmitting signals, a conductive via is provided to extend into the substrate integrated waveguide, and the signals are fed from the conductive via into the substrate integrated waveguide.

SUMMARY

One embodiment of the disclosure provides a circuit structure including a substrate integrated waveguide having a first substrate, a first conductive layer, a second conductive layer, and at least one waveguide conductive element, a second substrate, a waveguide signal feeding element, and a ring-shaped conductive element. The first substrate has a waveguide transmitting region. The first conductive layer and the second conductive layer are disposed on opposite surfaces of the first substrate, respectively, and cover the waveguide transmitting region. The at least one waveguide conductive element passes through the first substrate and electrically connected to the first conductive layer and the second conductive layer. The at least one waveguide conductive element surrounds the waveguide transmitting region. The second substrate is disposed on the substrate integrated waveguide. The second conductive layer is located between the first substrate and the second substrate. The waveguide signal feeding element passes through the second substrate and the second conductive layer and extends to the waveguide transmitting region of the first substrate. The waveguide signal feeding element is electrically insulated from the second conductive layer. The ring-shaped conductive element is disposed in the second substrate and surrounds the waveguide signal feeding element.

