Abstract: PIN diodes are ineffective as waveguide switches because the device and its connecting leads behave in total as an inductive obstacle.There is described herein a method of converting the resultant obstacle into a broad band series resonant circuit which may be switched into two states. With the diode conducting, the obstacle appears as a short-circuit across the guide. With the diode nonconducting, the obstacle appears as an open circuit across the guide.

Abstract: This invention comprises in combination a body of piezoelectric material, means for propagating an acoustic wave in a first mode, means for converting a portion of the acoustic wave energy into an acoustic wave in a second mode, a resonant structure in which the acoustic wave energy in the second mode is resonant, means for reconverting the acoustic wave energy in the second mode into surface acoustic wave energy in the first mode, means for providing a predetermined phase shift of the reconverted acoustic wave energy relative to the original propagated acoustic wave energy, and means for recovering the combined acoustic wave energy of the original and phase shift reconverted acoustic wave energies as an electric output signal.