J.D. Maines's Articles: (4)
AbstractWe have measured large, steady-state, spatial variations of electric field in photoconducting CdS, when the drift velocity of electrons exceeds the velocity of sound. The observations are interpreted in terms of a spatially dependent d.c. acousto-electric current from which the build-up of acoustic flux from thermal noise is estimated.
AbstractObservations show that the current through a thin platelet of photoconducting CdS forming an acoustic cavity is modulated at discrete frequencies (in the range 4 – 900 Mc/s), when the electron velocity exceeds the velocity of sound. This modulation is attributed to those thermally excited lattice waves for which there is round trip gain. The results are compared with White's small signal theory for acoustic amplification.
AbstractSurface wave devices with their combination of versatility, robustness and close approach to theoretical performance will, for many years ahead, be attractive components for use in the generation and time compression of the chirp waveforms used in many modern radars. This paper outlines detailed device design considerations and describes the incorporation of these devices into a practical radar system. The capabilities and limitations of the technology are discussed.
AbstractOscillations in current in the 1 to 5 GHz range have been observed when pulsed voltages are applied to thin platelets of semiconducting ZnO. Evidence is presented which establishes that they originate from the acousto - electric excitation of the vibrational modes of the platelet.