1. Actuator in the form of a single-layer or multi-layer flat plate, comprising:
an upper face;
a lower face;
at least one layer having two electrodes spaced from each other by a linear separating area and arranged opposite each other both on its upper face and on its lower face, said electrodes of said upper face are arranged at an offset from said electrodes of said lower face;
wherein said actuator comprises at least one friction element, said friction element being arranged along said separating area;
wherein the electrodes of said upper face are configured to oscillate deformations of said actuator along a first axial direction for driving a movable element in contact with said actuator in said first axial direction and said electrodes of said lower face are configured to oscillate deformations of said actuator along a second axial direction for driving the movable element in contact with said actuator in said second axial direction, when the electrodes of said upper face and the electrodes of said lower face are electrically actuated respectively.
2. Actuator according to claim 1, wherein said actuator has the shape of a polygonal plate.
3. Actuator according to claim 2, wherein said actuator has the shape of a square plate.
4. Actuator according to claim 1, wherein said electrodes of said upper face are arranged at an offset from said electrodes of said lower face by essentially 90\xb0.
5. Actuator according to claim 1, wherein said friction element is inserted into said actuator.
6. Actuator according to claim 5, wherein said friction element is inserted into a through hole provided in said actuator.
7. Actuator according to claim 1, wherein said actuator has a multilayer structure and an odd number of layers, where said respective electrodes facing each other on adjacent layers have the same orientation.
8. Actuator according to claim 7, wherein the uppermost layer and lowermost layer of said actuator are inactive layers.
9. Actuator according to claim 8, wherein said uppermost layer andor said lowermost inactive layer areis provided with termination electrodes.
10. Actuator according to claim 1, wherein said actuator is operated while exciting the second resonant frequency or an integral multiple of the second longitudinal resonance frequency.
11. Actuator according to claim 1, wherein, said electrodes of said upper face and said electrodes of said lower face are configured to oscillate hula-hoop-like deformations for rotationally driving a movable element in contact with said actuator by dephased electrically actuating said electrodes of said upper face and said electrodes of said lower face.
12. Actuator according to claim 1, wherein said deformations obtained by electrical actuation of said electrodes are located in the plane of said actuator.
13. Motor, comprising said actuator according to claim 1 and the moveable element to be driven by said actuator.
14. Actuator according to claim 1, wherein said actuator includes a piezoelectric material.
15. Actuator according to claim 1, wherein said at least one friction element is arranged at the center or at one end of said linear separating area.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An integrated heterodyne terahertz transceiver, comprising:
a quantum cascade laser, comprising
a substrate providing a bottom waveguide layer,
a plurality of layered heterostructures of two or more semiconductor alloys on the substrate,
a top waveguide layer on the layered semiconductor heterostructures, thereby providing an active semiconductor core between the top and bottom waveguide layers; and
at least one receiver formed in a hole in the top waveguide layer of the quantum cascade laser, comprising
a rectifying metal contact on the top surface of the layered semiconductor heterostructures exposed by the hole, thereby forming a metal-to-semiconductor Schottky diode, and
an antenna or horn connected to the rectifying metal contact for receiving a terahertz signal;
wherein the quantum cascade laser couples terahertz local oscillator power to the Schottky diode to mix with the received terahertz signal to provide an intermediate frequency output signal.
2. The integrated heterodyne terahertz transceiver of claim 1, wherein the substrate comprises a semiconductor or metal.
3. The integrated heterodyne terahertz transceiver of claim 2, wherein the semiconductor substrate comprises gallium arsenide.
4. The integrated heterodyne terahertz transceiver of claim 1, wherein the layered semiconductor heterostructures comprise a ridge structure.
5. The integrated heterodyne terahertz transceiver of claim 1, wherein the two or more semiconductor alloys comprise gallium arsenide and aluminum gallium arsenide.
6. The integrated heterodyne terahertz transceiver of claim 1, wherein the top waveguide layer comprises a metal or a doped semiconductor.
7. The integrated heterodyne terahertz transceiver of claim 6, wherein the metal comprises gold.
8. The integrated heterodyne terahertz transceiver of claim 6, wherein the metal comprises a metal stack of nickel, gold, and germanium, or palladium, germanium, and gold.
9. The integrated heterodyne terahertz transceiver of claim 1, wherein the bottom waveguide layer comprises a metal or a doped semiconductor.
10. The integrated heterodyne terahertz transceiver of claim 9, wherein the metal comprises gold.
11. The integrated heterodyne terahertz transceiver of claim 9, wherein the metal comprises a metal stack of nickel, gold, and germanium, or palladium, germanium, and gold.
12. The integrated heterodyne terahertz transceiver of claim 1, wherein the rectifying metal contact comprises titanium.
13. The integrated heterodyne terahertz transceiver of claim 1, wherein the antenna comprises a patch antenna.
14. The integrated heterodyne terahertz transceiver of claim 1, wherein the received terahertz signal has a frequency of 100 GHz to 10 THz.
15. The integrated heterodyne terahertz transceiver of claim 1, further comprising a coplanar waveguide or microstrip line on the layered semiconductor heterostructures to bring off the intermediate frequency output signal.