Microwave signal switching device, particularly of nanometric size, and electronic component incorporating such a device
A device for switching an electrical signal, controlled by an optical wave and having an on state and an off state, which can be inserted into a microwave transmission line, comprises a semiconductor substrate on which two conductive tracks are formed, these tracks being separated by a gap providing electrical insulation between the two tracks and each being connected to an input port and an output port, in the on state the electrical contact between the two tracks being established by illuminating the substrate in the region of the gap by means of the optical wave, the input impedance and the output impedance of said switching device being mismatched to the impedance of the transmission line in the off state and are matched to the impedance of the transmission line in the on state.
1. A device for switching an electrical signal, controlled by an optical wave and having an on state and an off state, which can be inserted into a microwave transmission line, said device comprising a semiconductor substrate on which two conductive tracks are formed, these tracks being separated by a gap providing electrical insulation between the two tracks and each being connected to an input port and an output port, in the on state an electrical contact between the two tracks being established by illuminating the substrate in a region of the gap by means of the optical wave, wherein a geometry of the conductive tracks are defined so that an input impedance an the output impedance of said switching device are mismatched to an impedance of the transmission line in the off state and are matched to the impedance of the transmission line in the on state.
2. The device as claimed in claim 1 , wherein in the off state, the input impedance and the output impedance are more than one kiloohm.
3. The device as claimed in claim 1 , wherein a width of the conductive tracks decreases from the input and output ports as far as the gap.
4. The device as claimed in claim 1 , wherein a width of the conductive tracks decreases linearly.
5. The device as claimed in claim 3 , wherein the tracks have a termination at the gap with a dimension equivalent to a width of the gap.
6. The device as claimed in claim 3 , wherein a structure of the device being of a coplanar type, comprising a ground plane on each side of the conductive tracks, a distance between ground planes and the tracks remaining substantially constant between the input and output ports and the gap.
7. The device as claimed in claim 1 , wherein a length of the gap is less than 1 μm.
8. The device as claimed in claim 1 , wherein a length of the gap is less than 0.5 μm.
9. An electronic component, incorporating a device as claimed in claim 1 .
10. The electronic component as claimed in claim 9 , wherein said component fulfills a function of a sample-and-hold circuit.