Ferroelectrically tuneable delay lines

Paper in proceeding, 2004

Ferroelectric (Ba/sub 0.25/Sr/sub 0.75/TiO/sub 3/) varactors are integrated on a Si substrate to form compact wideband true-time tuneable delay lines. The delay-line design is of the lumped element approach, implemented as a synthetic coplanar strip (CPS) line. The physical size of the delay lines is 2.0*0.33 mm/sup 2/. Up to 20 GHz, the measured delay time per unit length is approximately constant equal to 40 ps/mm (corresponding to a slow wave factor of 12) and the losses are about 0.049 dB/ps. The tuneability under 30 V DC-bias is 10%