A coaxial filter is provided. The coaxial filter comprises a first port, a second port, at least two capacitor segments each having two metal layers and a dielectric layer between them, and at least one grounded inductor stub connected to a metal layer of the at least two capacitor segments. The at least two capacitor segments are coaxially connected in series between the first port and the second port. An axis of the at least one grounded inductor stub is vertical to an axis of the at least two capacitor segments.