A delay line discriminator for IFM using a left-handed delay line

Recent developments in left-handed metamaterials and left-handed transmission lines have led to new approaches to the design of radio frequency components such as branch line couplers. In this paper, the design of a delay line discriminator for instantaneous frequency measurement (IFM) is investigated, where the delay line section is replaced by a composite right/left-hand (CRLH) transmission line. To demonstrate the CRLH design approach, experimental measurements and simulation results are compared for a 100 MHz delay line discriminator. The inherent phase advance of the CRLH transmission line structure is shown to reverse the slope of the frequency discriminator when compared to a right-handed transmission line structure.