Ultra-wideband miniaturized omnidirectional antennas via multi-mode three-dimensional (3-D) traveling-wave (TW)
First Claim
1. An omnidirectional antenna comprising:
- a plurality of traveling-wave (TW) structures comprising at least one ultra-wideband low-profile two-dimensional (2-D) surface-mode TW structure, the plurality of TW structures being adjacent to each other, and wherein the surface-mode TW structure is excited in mode-0 and comprises a 2-D surface-mode TW radiator for omnidirectional radiation, the 2-D surface-mode TW structures being further configured to have a diameter less than λ
L/2 and a thickness less than λ
L/10, where λ
L is the free-space wavelength at the lowest frequency of operation of the 2-D surface-mode TW structures;
a frequency-selective coupler placed in between adjacent TW structures;
a feed network, wherein the feed network excites the plurality of TW structures in mode-0; and
a conducting ground surface, wherein the conducting ground surface is of a canonical shape, the conducting ground surface further being positioned at a bottom side of the antenna, and having a surface area covering at least the projection of the antenna.
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Accused Products
Abstract
A class of ultra-wideband miniaturized traveling-wave (TW) antennas comprising a conducting ground surface at the base, a plurality of TW structures having at least one ultra-wideband low-profile two-dimensional (2-D) surface-mode TW structure, a frequency-selective coupler placed between adjacent TW structures, and a feed network. In one embodiment, a 2-D surface-mode TW structure is positioned above the conducting ground surface, a normal-mode TW structure placed on top with an external frequency-selective coupler placed in between; continuous octaval bandwidth of 14:1 and size reduction by a factor of 3 to 5 are achievable. In other embodiments using at least two 2-D TW structures and a dual-band feed network, a continuous bandwidth over 100:1, and up to 140:1 or more, is reachable. In yet another embodiment, ultra-wideband multi-band performance over an octaval operating bandwidth up to 2000:1 or more is feasible.
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Citations
24 Claims
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1. An omnidirectional antenna comprising:
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a plurality of traveling-wave (TW) structures comprising at least one ultra-wideband low-profile two-dimensional (2-D) surface-mode TW structure, the plurality of TW structures being adjacent to each other, and wherein the surface-mode TW structure is excited in mode-0 and comprises a 2-D surface-mode TW radiator for omnidirectional radiation, the 2-D surface-mode TW structures being further configured to have a diameter less than λ
L/2 and a thickness less than λ
L/10, where λ
L is the free-space wavelength at the lowest frequency of operation of the 2-D surface-mode TW structures;a frequency-selective coupler placed in between adjacent TW structures; a feed network, wherein the feed network excites the plurality of TW structures in mode-0; and a conducting ground surface, wherein the conducting ground surface is of a canonical shape, the conducting ground surface further being positioned at a bottom side of the antenna, and having a surface area covering at least the projection of the antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A multi-mode three-dimensional (3-D) low-profile traveling-wave (TW) omnidirectional antenna covering one or more ultra-wide bandwidths at high frequencies and separate distant low-frequency bands, and conforming to a surface of a platform, the 3-D TW antenna comprising:
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a conducting ground surface, which is in the form of a canonical shape, wherein the conducting ground surface conforms to a portion of the surface of a platform, the conducting ground surface being placed under the 3-D TW antenna and having a set of dimensions at least as large as those of the surface area of the 3-D TW antenna projected on the surface of the platform; a plurality of TW structures on top of the conducting ground surface, wherein each of the TW structure covers separate frequency band so as to enable the omnidirectional antenna to span in aggregate multiple bands over an ultra-wide range of frequencies, wherein the TW structures include at least one ultra-wideband low-profile 2-D surface-mode TW structure, and wherein the ultra-wideband low-profile 2-D surface-mode TW structure has a diameter less than λ
L/2, where λ
L is the free-space wavelength at the lowest frequency of operation of the 2-D surface-mode TW structures, the TW structures being adjacent to each other and stacked above the conducting ground surface;a frequency-selective coupler placed in between adjacent TW structures; at least one-dimensional (1-D) transmission-line antenna positioned adjacent to the plurality of TW structures, wherein the 1-D transmission-line antenna is coupled to a top side of the plurality of TW structures via a low-pass coupler to cover a plurality of separate distant low frequencies; and a feed network matching the impedances of the TW structures and the 1-D transmission-line antenna with the impedance of an external connector. - View Dependent Claims (16)
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17. An omnidirectional antenna comprising:
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a conducting ground surface being positioned at a bottom side of the antenna, a plurality of traveling-wave (TW) structures on top of the conducting ground surface and covering a range of operating frequencies, wherein each TW structure covers a separate frequency band; a frequency-selective coupler placed in between adjacent TW structures; and a feed network matching an impedance of the TW structures with an impedance of an external connector. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification