Apparatus for providing a controllable signal delay along a transmission line
Apparatus for providing a controllable signal delay along a transmission line, which apparatus comprises a transmission line conductor on a dielectric medium comprised wholly or partially or a semiconductor material, and adjacent periodically separated electromagnetically-coupled elements, the coupling between the elements and the transmission line conductor being controllable through photonic and/or electrical injection of electrical carriers into the dielectric medium, whereby the apparatus is such as to enable control of the velocity of electromagnetic propagation along the transmission line and thereby through the apparatus.
1. Apparatus for providing a controllable signal delay along a transmission line, which apparatus comprises a transmission line conductor on a dielectric medium comprised wholly or partially of a semiconductor material, and adjacent periodically separated electromagnetically-coupled elements, the coupling between the elements and the transmission line conductor being controllable through photonic and/or electrical injection of electrical carriers into the dielectric medium, whereby the apparatus is such as to enable control of the velocity of electromagnetic propagation along the transmission line and thereby through the apparatus.
2. Apparatus according to claim 1 in which the transmission line conductor is a microstrip conductor.
3. Apparatus according to claim 2 in which the microstrip conductor has a structure comprising a thin metallic guide separated from a ground plane by a dielectric medium.
4. Apparatus according to claim 1 in which the transmission line conductor is an image line conductor, a fin line conductor, a slot line conductor, a coplanar waveguide conductor, an inverted microstrip conductor, a trapped inverted microstrip conductor, or a suspended strip line conductor.
5. Apparatus according to claim 1 in which the coupled elements are configured as arrays of slots or other electromagnetic structures.
6. Apparatus according to claim 1 in which the coupled elements are in a pattern which is such as to produce a controllable electromagnetic band-stop or band-pass filter.
7. Apparatus according to claim 1 and which is used to excite an array of antenna elements, thereby enabling controllable directivity of the array of antenna elements.
8. Apparatus according to claim 7 in which coupling to the antenna elements is enabled through locally generated filamentary plasmas.
9. Apparatus according to claim 1 and including optical means for generating locally generated filamentary plasma by the illumination of the dielectric medium.
10. Apparatus according to claim 1 and including electrical means for generating locally generated filamentary plasma by the injection of electrical carriers into the dielectric medium.
11. Apparatus according to claim 1 and including optical means and electrical means for generating locally generated filamentary plasma by illumination of the dielectric medium and electrical injection of electrical carriers into the dielectric medium.
12. Apparatus according to claim 7 in which the electromagnetic polarisation of the antenna is selectable through control of the coupling to the antenna elements.
13. Apparatus according claim to 1 and incorporated within a multiplicity of antenna sub-arrays, the collective effect of the sub-arrays enabling complex controllable antenna functionality.
14. Apparatus according to claim 1 and designed by calculation of geometry and material properties to perform in specific applications relating to telecommunications, radar, guidance, aerospace, medical scanning, inspection or other forms of sub-surface imaging.