Performance of Spiral-Shaped Dispersive Delay Structures for Realtime Analog Signal Processing

This paper proposes a spiral-shaped dispersive delay structure (Spiral-DDS) composed of vertically stacked spiral coils and vertical vias. This all-pass network architecture can produce a large group delay peak at a certain frequency in a few GHz range. Basic performance of the Spiral-DDS are studied theoretically, and the group delay with more than 6 ns was successfully generated by a compact multilayered architecture with dimensions of 6.0 x 6.0 x 1.18 mm (3). This paper also reports that the most of losses occurred in DDS comes from conductor loss, not from dielectric loss.