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US 4,745,378 AGranted
Surface acoustic wave device
AssigneeClarion Co., Ltd.
InventorsTeruo Niitsuma, Takeshi Okamoto, Shoichi Minagawa
Life of this patent
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Abstract
The surface acoustic wave device includes a plurality of output gate electrodes provided between two signal input transducers on a piezoelectric layer on a semiconductor substrate, so that each output gate electrode receives a bias voltage unique to it and supplies an output signal based on the unique bias voltage.
Claims9
A surface acoustic wave device comprising:
- a semiconductor substrate;
- a piezoelectric film provided on one surface of said substrate;
- two signal input transducers which are provided at spaced locations on said piezoelectric film and can each enter a signal thereinto;
- a plurality of electrically separate output gate electrodes provided on said piezoelectric film between said input transducers, said substrate having a plurality of interaction regions which are each associated with a respective said gate electrode;
- bias voltage applying means connected directly to each said output gate electrode for applying to each of said output gate electrodes a respective bias voltage independently selected to optimize a capacity-to-voltage characteristic in the associated interaction region of said substrate, said bias voltage applying means including a plurality of independently variable bias voltage sources which are each connected to a respective said output gate electrode;
- and
- output signal extracting means for extracting a respective output signal from each of said output gate electrodes, said output signal extracting means including a plurality of DC blocking capacitors which each have one end connected to a respective one of said output gate electrodes, each said output signal being extracted through a respective said blocking capacitor.
4 more elements
A surface acoustic wave device, comprising:
- a semiconductor substrate having first and second surfaces on opposite sides thereof;
- an insulation film provided on said first surface of said substrate;
- a piezoelectric film provided on said insulation film;
- two signal input transducers provided at spaced positions on said piezoelectric film;
- a ground electrode provided on said second surface of said semiconductor substrate and connected to ground;
- a plurality of signal output gate electrodes provided on said piezoelectric film between said two signal input transducers;
- optimum bias applying means connected to said output gate electrodes for supplying each said output gate electrode with an optimum d.c. bias voltage which optimizes the capacitance-voltage characteristic of a respective region under such output gate electrode where an interaction occurs between surface acoustic waves and a depletion layer provided along said first surface of said substrate;
- and
- output signal extracting means for extracting a respective output signal from each said output gate electrode, said output signal extracting means including a plurality of d.c. blocking capacitors which each have a terminal connected to a respective said output gate electrode so that each said output signal is extracted through a respective said d.c. blocking capacitor.
6 more elements
Dependencies are inferred from the claim text.