In this article, three new circuits for realising frequency-dependent negative resistance (FDNR) are proposed. All proposed circuits employ a single fully differential current conveyor, grounded capacitors and resistor. Proposed circuits consist of minimum number of passive and active elements. All proposed circuits are lossless FDNR. The performance of the proposed FDNR is demonstrated on the third-order Butterworth low-pass filter. Simulation results are included to verify the theory.