High performance SAW dispersive delay lines for low time bandwidth using periodically sampled transducers

It is shown that it is possible to construct dispersive devices with only periodic transducers. This structure allows better design accuracy and easier device manufacture. Gating or Frensel sidelobes can be rejected by approximately 12 dB by adding frequency extensions to the expander. These two techniques have been used to design a 10- mu s dispersion and 7.35-MHz-bandwidth nonlinear FM system. A 46 dB sidelobe level was achieved experimentally for an analyzed 50 dB level.<>