In frequency-modulated dierential chaos shift keying (FM-DCSK), the separation of the chaotic reference and information-bearing wavelets is performed in time domain. This separation method not only limits the attainable data rate but also demands delay components in transceiver circuits. Due to the fact that wideband radio frequency (RF) delay lines are extremely diffcult to implement with CMOS technology in ultra wideband communications, a new phase-separated FM-DCSK modulation scheme is presented in this paper to increase the data rate and to avoid the use of delay lines in both the transmitter and the receiver circuits. The feasible congurations of transmit- ter and detector are given. Besides, bit error rate (BER) performance of the proposed system is evaluated by both analysis and Monte Carlo simulations over additive white Gaussian noise (AWGN) channel.