An isolator includes a conditioning circuit configured to filter signals communicated therethrough. The isolator also includes a coupling member comprising an anti-rotation feature. The anti-rotation feature is configured to prevent the conditioning circuit from rotating with respect to the coupling member to maintain a stable ground contact for the conditioning circuit. The isolator also includes a first annular circuit positioned around the coupling member. The isolator also includes a second annular circuit positioned around the coupling member and axially offset from the first annular circuit. The first and second annular circuits are configured to provide radio-frequency (RF) coupling with the coupling member.