left handed transmission lines

Am trying to make a microstrip transmission line as a delay line. I was initially intrigued by a couple of papers touting delay lines with very short phyical length but long time delays over a broad bandwidth. One paper touts 2 nS of delay in a 60 mm length.

But when I take the papers and simulate them with Sonnet, I am getting nothing like the time delays the papers are quoting. I am only getting maybe twice what a standard 50 ohm transmission line would get, not the 10 x the time delay promised.

Anyone else try to design a delay line with left handed elements, and did you succeed? Either I am doing something very wrong, or these papers are wildly over optimistic in their predictions!

Hello,

In my opinion, such metamaterials that modifies er and ur are narrow band in nature, so you can't use them as a delay line for wide band signals. With "wide band" I mean BW/fc > 0.5.

Commercial delay lines are usually made of a meander stripline in a high-k dielectric. Try to look at Kyocera or other ceramic-makers.