A New Low-Loss, Single-Bounce, Reflective Array Filter Using Hyperbolically Tapered Transducers

A new reflective array geometry for making dispersive filters is being reported which offers a significant improvement in both bandwidth and insertion loss over the conventional RAC technique. The present technique uses hyperbolically tapered transducers to launch and detect the SAWS scattered from a single reflective array. The transducers have demonstrated a bandwidth of up to 100 percent. Two dispersive filters are presented to illustrate the performance. The first device has a 50 percent bandwidth of 175 MHz and a dispersive delay of 20 microseconds for a TB product of 3500. The insertion loss is 33 dB which is significantly better than any other RAC with a comparable TB product. The second, a rather narrow 5 MHz bandwidth centered at 60 MHz with a time delay of 30 microseconds, has an insertion loss under IO dB. This is better than 10 dB lower than the published results of any other reflective array dispersive filter.