Starting from the common 4-port configuration of CRLH (Composite Right/Left Handed) based Differential Phase Shifter (DPS), by connecting the two input ports, a 3-port configuration is proposed. Both DPS topologies are analyzed by means of an analytical approach and design procedure is proposed. The 3-port DPS has a convenient topology for application such as antenna phased array feeding circuits. It is shown that the frequency bandwidth of this DPS may be maximized if a transmission line, having an optimum length, is inserted before the CRLH structure. A possible layout for 3-port topology consisting of transmission lines and chip capacitors and inductors is designed and electromagnetic analysis is performed.