Feed network and electromagnetic radiation source
View Patent ↗An antenna may include a volume polarization current radiator and a feed network. The volume polarization current radiator, includes a dielectric solid (such as a dielectric strip), and a plurality of closely-spaced excitation elements ( 24 ), each excitation element ( 24 ) being configured to induce a volume polarization current distribution in the dielectric solid proximate to the excitation element when a voltage is applied to the excitation element. The feed network is coupled to the volume polarization current radiator. The feed network also includes a plurality of passive power divider elements ( 32 ) and a plurality of passive delay elements (d 1 -d 6 ) coupling the first port ( 30 ) and the plurality of second ports ( 108, 109, 164 ), the plurality of power divider elements ( 32 ) and the plurality of phase delay elements (d 1 -d 6 ) being configured such that a radio-frequency signal that is applied to the first port ( 30 ) experiences a progressive change of phase as it is coupled to the plurality of second ports ( 108, 109, 164 ) so as to cause the volume polarization current distribution to propagate along the dielectric solid.
1. An antenna, comprising:
a) a volume polarization current radiator, including:
i) a dielectric solid, and
ii) a plurality of closely-spaced excitation elements, each excitation element being configured to induce a volume polarization current distribution in the dielectric solid proximate to the excitation element when a voltage is applied to the excitation element; and
b) a feed network coupled to the volume polarization current radiator, the feed network comprising:
i) a first port;
ii) a plurality of second ports, each of the plurality of second ports being coupled to at least one of the plurality of excitation elements; and
iii) a plurality of passive power divider elements and a plurality of passive delay elements coupling the first port and the plurality of second ports, the plurality of power divider elements and the plurality of phase delay elements being configured such that a radio-frequency signal that is applied to the first port experiences a progressive change of phase as it is coupled to the plurality of second ports so as to cause the volume polarization current distribution to propagate along the dielectric solid.
2. The antenna of claim 1 , wherein the progressive change of phase comprises a progressive change of time delay between the first port and at least some of the plurality of second ports.
3. The antenna of claim 1 , wherein the progressive change of phase comprises adding phase delay in approximately equal amounts.
4. The antenna of claim 1 , wherein the progressive change of phase comprises adding phase delay in diminishing amounts.
5. The antenna of claim 1 , wherein the dielectric solid is linear strip, and the plurality of closely-spaced excitation elements comprises a linear array.
6. The antenna of claim 1 , wherein the dielectric solid is curved strip, and the plurality of closely-spaced excitation elements comprises a curved array.
7. The antenna of claim 1 , wherein the dielectric solid is circular strip, and the plurality of closely-spaced excitation elements comprises a circular array.
8. The antenna of claim 1 , wherein the plurality of power divider elements and the plurality of phase delay elements are configured such that when a radio-frequency signal is applied to the first port, the phase of the radio-frequency signal is progressively changed as it is coupled to the plurality of second ports so as to cause the volume polarization current distribution to propagate along the dielectric solid at a velocity less than the speed of light in a vacuum.
9. The antenna of claim 1 , wherein the plurality of power divider elements and the plurality of phase delay elements are configured such that when a radio-frequency signal is applied to the first port, the phase of the radio-frequency signal is progressively changed as it is coupled to the plurality of second ports so as to cause the volume polarization current distribution to propagate along the dielectric solid at a velocity greater than the speed of light in a vacuum.
10. The antenna of claim 1 , wherein the plurality of power divider elements and the plurality of phase delay elements are configured such that when a radio-frequency signal is applied to the first port, the phase of the radio-frequency signal is progressively changed as it is coupled to the plurality of second ports so as to cause the volume polarization current distribution to accelerate while propagating along the dielectric solid.
11. The antenna of claim 1 , wherein the plurality of closely spaced excitation elements comprises a first excitation element and a second excitation element,
a) the first excitation element being adjacent to the second excitation element, wherein a center of the first excitation element is separated from a center of a second excitation element by an element distance;
b) the feed network imposing a first aggregate amount of time delay between the first port and the first excitation element; and
c) the feed network imposing a second aggregate amount of time delay between the first port and the second excitation element, the first aggregate amount of time delay being less than the second aggregate amount of time delay.
12. The antenna of claim 11 , wherein the element distance is greater than a difference between the first aggregate amount of time delay and the second aggregate amount of time delay.
13. The antenna of claim 11 , wherein the element distance is less than a difference between the first aggregate amount of time delay and the second aggregate amount of time delay.
14. The antenna of claim 11 , wherein the plurality of closely spaced excitation elements further comprises a third excitation element;
a) the second excitation element being adjacent to the third excitation element, wherein the center of the second excitation element is separated from a center of a third excitation element by the element distance;
b) the feed network imposing a third aggregate amount of time delay between the first port and the third excitation element, the third aggregate amount of time delay being greater than the second aggregate amount of time delay.
15. The antenna of claim 11 , wherein the element distance is greater than a difference between the first aggregate amount of time delay and the second aggregate amount of time delay; and a difference between the second aggregate amount of time delay and the third aggregate amount of time delay is less than the difference between the first aggregate amount of time delay and the second aggregate amount of time delay.
16. The antenna of claim 1 , wherein at least one of the plurality of passive delay elements comprises a fixed-length transmission line that imparts a fixed amount of time delay.
17. The antenna of claim 1 , wherein at least one of the plurality of passive delay elements comprises an adjustable phase shifter that imparts a variable amount of time delay.
18. The antenna of claim 1 , wherein at least one of the plurality of passive delay elements comprises an adjustable phase shifter that imparts a variable amount of time delay and at least one of the plurality of phase delay elements comprises a fixed-length transmission line that imparts a fixed amount of time delay.
19. An method of producing electromagnetic radiation, the method comprising:
a) providing a volume polarization current radiator, the volume polarization current radiator including:
i) a dielectric solid, and
ii) a plurality of closely-spaced excitation elements, each excitation element being configured to induce a volume polarization current distribution in the dielectric solid proximate to the excitation element when a voltage is applied to the excitation element;
b) coupling a feed network to the volume polarization current radiator, the feed network comprising:
i) a first port;
ii) a plurality of second ports, each of the plurality of second ports being coupled to at least one of the plurality of excitation elements; and
iii) a plurality of passive power divider elements and a plurality of passive delay elements coupling the first port and the plurality of second ports;
c) the plurality of power divider elements and the plurality of phase delay elements progressively changing phase between the first port and the plurality of second ports; and
d) applying a radio-frequency signal to the first port, the radio-frequency signal propagating through the feed network to the plurality of second ports thereby causing a volume polarization current distribution to propagate along the dielectric solid.
20. The method of claim 19 , wherein the steps of progressively changing phase and applying radio-frequency signal causes the volume polarization current distribution to propagate along the dielectric solid at a velocity less than the speed of light in a vacuum.
21. The method of claim 19 , wherein the steps of progressively changing phase and applying radio-frequency signal causes the volume polarization current distribution to propagate along the dielectric solid at a velocity greater than the speed of light in a vacuum.
22. The method of claim 19 , wherein the steps of progressively changing phase and applying radio-frequency signal causes the volume polarization current distribution to accelerate while propagating along the dielectric solid.
23. The method of claim 19 , wherein the step of progressively changing phase further comprises varying phase differences between the second ports.