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 × 6.0 × 1.18 mm3. This paper also reports that the most of losses occurred in DDS comes from conductor loss, not from dielectric loss.