Electromagnetic dispersive delay line
First Claim
1. A linear dispersive delay line, comprising:
- A. a surface-electromagnetic-wave guide comprising an elongated dielectric body having a propagation path therethrough for conducting surface electromagnetic waves therealong, the dielectric body having a smallest cross-sectional dimension perpendicular to the propagation path which dimension varies with distance along the propagation path in such a manner that the wave guide is dispersive, in that the wave guide has a substantially linear relationship to frequency of the time required for an electromagnetic wave to propagate through the wave guide, throughout a frequency band wider than that throughout which an elongated surface-electromagnetic-wave guide of the same dielectric material but of uniform cross section would;
B. an input coupler for launching signals received thereat as surface electromagnetic waves into the dielectric body; and
C. an output coupler for providing a signal representative of the surface electromagnetic waves received thereat from the dielectric body.
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Accused Products
Abstract
An electromagnetic dispersive delay line (10) includes a dielectric strip (28) as well as a coupler (24, 34, 36, and 38) for launching surface electromagnetic waves into the dielectric strip. The upper surface of the dielectric strip (28) is left exposed to the air in order to provide an interface with a lower-permittivity medium of propagation. This permits a surface-electromagnetic-wave propagation mode. The thickness of the dielectric strip (28) is varied along its length so as to result in a linear relationship of delay to frequency throughout a predetermined frequency range. Preferably, a conductive strip (26) spaced from the dielectric strip extends along the surface-wave propagation path in the region occupied by the evanescent field external to the dielectric strip (28). This conductive strip (26) modifies the phase relationships between the electric and magnetic fields in the evanescent-field region so as to cause some of the power transmission to occur outside of the dielectric strip. This modifies the dispersion curve so as to extend the bandwidth of significant dispersion.
154 Citations
18 Claims
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1. A linear dispersive delay line, comprising:
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A. a surface-electromagnetic-wave guide comprising an elongated dielectric body having a propagation path therethrough for conducting surface electromagnetic waves therealong, the dielectric body having a smallest cross-sectional dimension perpendicular to the propagation path which dimension varies with distance along the propagation path in such a manner that the wave guide is dispersive, in that the wave guide has a substantially linear relationship to frequency of the time required for an electromagnetic wave to propagate through the wave guide, throughout a frequency band wider than that throughout which an elongated surface-electromagnetic-wave guide of the same dielectric material but of uniform cross section would; B. an input coupler for launching signals received thereat as surface electromagnetic waves into the dielectric body; and C. an output coupler for providing a signal representative of the surface electromagnetic waves received thereat from the dielectric body. - View Dependent Claims (2)
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3. A linear dispersive delay line, comprising:
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A. a surface-electromagnetic-wave guide comprising an elongated dielectric body having a propagation path therethrough for conducting surface-electromagnetic-waves therealong, the dielectric body having a cross-sectional dimension perpendicular to the propagation path which dimension varies with distance along the propagation path in such a manner that the wave guide is dispersive, in that the wave guide has a substantially linear relationship to frequency of the time required for an electromagnetic wave to propagate through the wave guide, throughout a frequency band wider than that throughout which an elongated surface-electromagnetic-wave guide of the same dielectric material but of uniform cross section would; B. an input coupler for launching signals received thereat as surface electromagnetic waves into the dielectric body; and C. an output coupler for providing a signal representative of the surface electromagnetic waves received thereat from the dielectric body, wherein the dielectric body forms a longitudinal surface extending along the propagation path and wherein the delay line further includes a ground-plane conductor upon which the dielectric body is mounted with the longitudinal surface flush against it so that electromagnetic radiation impinging upon the longitudinal surface from within the dielectric body is reflected at the longitudinal surface by the ground-plane conductor. - View Dependent Claims (4, 5, 6, 7, 8, 9)
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10. A linear dispersive delay line, comprising:
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A. a surface-electromagnetic-wave guide comprising an elongated dielectric body having a propagation path therethrough for conducting surface electromagnetic waves therealong, the dielectric body having a cross-sectional dimension perpendicular to the propagation path which dimension varies with distance along the propagation path in such a manner that the wave guide is dispersive, in that the wave guide has a substantially linear relationship to frequency of the time required for an electromagnetic wave to propagate through the wave guide, throughout a frequency band wider than that throughout which an elongated surface-electromagnetic-wave guide of the same dielectric material but of uniform cross section would; B. an input coupler for launching signals received thereat as surface electromagnetic waves into the dielectric body; C. an output coupler for providing a signal representative of the surface elecromagnetic waves received thereat from the dielectric body; and D. a plurality of input couplers for launching signals received thereat as surface electromagnetic waves into the dielectric body and a plurality of output couplers for providing signals representative of the surface electromagnetic waves received thereat from the dielectric body. - View Dependent Claims (11, 12, 13)
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14. An electromagnetic dispersive delay line, comprising:
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A. a surface--electromagnetic-wave guide that includes an input port, an output port, and a dielectric body through which electromagnetic radiation propagates from the input port to the output port along a propagation path therethrough, the dielectric body having at least one free surface extending along the propagation path and being substantially free from obstructions that would prevent formation, adjacent to the free surface, of the evanescent fields that characterize a surface electromagnetic wave; B. an input coupler for coupling an electrical signal into the wave guide as surface electromagnetic waves that travel along the propagation path; C. an output coupler for coupling from the propagation path signals introduced into the dielectric wave guide by the input coupler; and D. first and second conductors coupled at opposite ends thereof to the input and output couplers and extending along the path of propagation and between the input and output ports on opposite sides of the dielectric body, at least the first conductor being spaced from the free surface but being disposed in the evansecent field, whereby the conductors act as a transmission line between the input and output couplers at low frequencies and at higher frequencies modify behavior of a channel formed between the input and output couplers so as to extend the frequency band in which the channel is significantly dispersive and to reduce the attenuation in this band. - View Dependent Claims (15)
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16. An electromagnetic dispersive delay line, comprising:
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A. a surface-electromagnetic-wave guide that includes an input port, an output port, and a dielectric body through which electromagnetic radiation propagates from the input port to the output port along a propagation path therethrough, the dielectric body having at least one free surface extending along the propagation path and being substantially free from obstructions that would prevent formation, adjacent to the free surface, of the evanescent fields that characterize a surface electromagnetic wave, wherein the dielectric body has a cross-sectional dimension perpendicular to the propagation path which dimension varies with distance along the propagation path in such a manner that the wave guide is dispersive, in that the wave guide has a substantially linear relationship to frequency of the time required for an electromagnetic wave to propagate through the wave guide, throughout a frequency band wider than that throughout which an elongated surface-electromagnetic-wave guide of the same dielectric material but of uniform cross section would; B. an input coupler for coupling an electrical signal into the dielectric wave guide as surface electromagnetic waves that travel along the propagation path; C. an output for coupling from the propagation path signals introduced into the dielectric wave guide by the input coupler; and D. first and second conductors coupled at opposite ends thereof to the input and output couplers and extending along the path of propagation and between the input and output ports on opposite sides of the dielectric body, at least the first conductor being spaced from the free surface but being disposed in the evanescent field, whereby the conductors act as a transmission line between the input and output couplers at low frequencies and at higher frequencies modify behavior of a channel formed between the input and output couplers so as to extend the frequency band in which the channel is significantly dispersive and to reduce the attenuation in this band. - View Dependent Claims (17, 18)
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Specification