Compact, tunable large group delay line

In this paper, we present a compact, tunable delay line based on left‐handed nonlinear transmission line (LH NLTL). The widely tunable range of the large group delay is achieved by controlling a reverse bias voltage of series varactors in the LH NLTL. The proposed tunable delay line can be made in a very compact form because its size is dominated by the cascaded varactors. Our experiment shows that the fabricated prototype exhibits tunable group delay between 1.2 and 2.2 ns at a frequency of 1.42 GHz and good return loss. The circuit size is merely 1.6 cm in length. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2893–2895, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24747