In an aspect, an apparatus is disclosed that includes a surface-mounted integrated circuit package housing an active oscillator circuit; an integrated ceramic resonator formed from a ceramic substrate having an upper planar surface receiving the surface-mounted integrated circuit package, the integrated ceramic resonator including a plurality of conductive walls forming a conductive periphery of a ceramic cavity in the ceramic substrate, a conductive rod extending vertically into the ceramic cavity, wherein the conductive rod is isolated from contact with the conductive periphery of the ceramic cavity, a first conductive material extending vertically through the upper planar surface of the ceramic substrate for connecting the conductive periphery of the ceramic cavity to the surface-mounted integrated circuit package housing the active oscillator circuit; and a second conductive material extending through the upper planar surface of the ceramic substrate for connecting the conductive rod to the surface-mounted integrated circuit package.