A wideband time-delay line inspired by CRLH TL unit cell

This paper presents the design of ultra-wideband time-delay lines in microwave frequency inspired by the composite right/left-handed transmission line (CRLH TL) unit cell. A rotated version of the conventional CRLH TL unit cell is used to achieve an ultrawide bandwidth. For comparison, the time-delay lines using the conventional CRLH TL unit cells, right-handed transmission line (RH TL) and periodic microstrip line (PML) are also designed, optimized and fabricated. Simulation and measurement results show that, for the same length of 60 mm, our proposed time-delay line has an ultrawide bandwidth and much longer time delay than those of the RH TL and PML ones. It also has the advantages of high return loss and low insertion loss.