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US 6,646,618 B2Granted
Low-profile slot antenna for vehicular communications and methods of making and designing same
AssigneeHRL Laboratories, LLC
InventorDaniel Sievenpiper
Life of this patent
Estimating the term…
Abstract
A crossed slot antenna, a method of fabricating same and a method of designing same. The antenna includes a cavity structure having conductive material on opposed surfaces thereof; and two slots in said conductive material, the slots having slightly different lengths and intersecting each other at or close to a 90 degree angle.
Claims64
A crossed slot antenna having a resonance frequency, said antenna comprising:
- (a) an electrically conductive structure defining a cavity therein;
- (b) first and second slots formed in said electrically conductive structure, said slots having different lengths such that said one slot has a resonance frequency above the resonance frequency of the antenna and such that said second slot has a resonance frequency below the resonance frequency of the antenna;
- and
- (c) a common feed point arranged to couple a radio frequency signal from the slots to said common feed point.
1 more element
A method of fabricating a crossed slot antenna comprising:
- (a) forming a cavity using a printed circuit board plated with metal on opposed surfaces;
- (b) forming two slots in said plated metal, said slots having different lengths and intersecting each other at approximately a 90 degree angle;
- and
- (c) forming a metal plated via in said printed circuit board, said metal plated via defining a common feed point for said slots.
1 more element
An antenna unit for mounting on a vehicle, the antenna unit comprising:
- (a) a support surface and a mounting device for mounting the antenna unit on the vehicle;
- (b) an antenna adapted for receiving circularly polarized radio frequency signals in at least directions oblique to said support surface, said antenna also adapted for receiving linearly radio frequency polarized signals;
- (c) a protective cover covering said antenna;
- and
- (d) a circuit coupled to said antenna, said circuit capable of conducting said circularly polarized radio frequency signals and said linearly polarized radio frequency signals,
- wherein said antenna comprises a slot antenna having two slots, said slot antenna having a resonance frequency, said slots each having a resonance frequency, the resonance frequency of the one slot being above the resonance frequency of the antenna and the resonance frequency of the other slot being below the resonance frequency of the antenna.
3 more elements
A method of receiving circularly polarized radio frequency signals comprising:
- (a) providing a slot antenna having two slots which cross each other in a surface of a cavity structure;
- (b) varying the lengths of the slots so that the slots have different individual resonance frequencies;
- and
- (c) providing an antenna feed point on said surface which is spaced from both of said slots.
1 more element
A method of designing a crossed slot antenna capable of receiving both circularly polarized radio frequency signals and linearly polarized radio frequency signals, the crossed slot antenna having a pair of crossed slots formed in a surface of a cavity structure, said method comprising the steps of:
- (a) calculating an effective dielectric constant in the slots of the crossed slot antenna that is the average of dielectric constant of the cavity and that of any radome or other environment located above the slots;
- (b) calculating an effective index of refraction n, where n={square root over (∈average)} and where ∈average=the dielectric constant calculated in step (a);
- (c) determining an initially calculated average length of the slots of λ/2n where λ=the wavelength of a desired resonance frequency of the crossed slot antenna;
- (d) calculating an inherent bandwidth of the crossed slot antenna based on the formula 6πV/λ3 where V=the volume of the cavity structure;
- (e) determining an initially calculated length of each slot by adding, for one slot, and subtracting, for the other slot, a distance equal to one-half of the inherent bandwidth, expressed as a percentage, of the antenna;
- (f) adjusting the initially calculated length of each slot by experiment.
3 more elements
A method of fabricating a crossed slot antenna comprising:
- (a) forming a cavity structure having conductive material on opposed surfaces thereof;
- and
- (b) forming two slots in said conductive material, said slots having different lengths and intersecting each other at or close to a 90 degree angle,
- wherein the crossed slot antenna has a resonance frequency and wherein the slots each have a resonance frequency, the resonance frequency of the one slot being above the resonance frequency of the antenna and the resonance frequency of the other slot being below the resonance frequency of the antenna.
1 more element
A crossed slot antenna comprising:
- (a) a cavity structure having conductive material on or forming opposed surfaces thereof;
- and
- (b) two slots in said conductive material, said slots having different lengths and intersecting each other at or close to a 90 degree angle,
- wherein the crossed slot antenna has a resonance frequency and wherein the slots each have a resonance frequency, the resonance frequency of one slot being above the resonance frequency of the antenna and the resonance frequency of the other slot being below the resonance frequency of the antenna.
1 more element
A slot antenna comprising:
- (a) a cavity structure having conductive material on or forming opposed surfaces thereof;
- (b) at least one slot in the conductive material on a first surface of the cavity structure;
- and
- (c) a feed structure consisting of only a single feed point for said slot, the feed point being disposed in and penetrating said cavity structure, said feed point being coupled to said first surface at a point thereon which is spaced from said slot.
1 more element
A crossed slot antenna for receiving or transmitting circularly polarized signals or linearly polarized signals comprising:
- an electrically conductive structure defining a cavity therein;
- first and second slots formed in said electrically conductive structure, said slots having different lengths;
- and
- a circuit coupled to said first and second slots, said circuit capable of conducting both said circularly polarized signals and linearly polarized signals,
- wherein the crossed slot antenna has a resonance frequency and wherein the slots each have a resonance frequency, the resonance frequency of one slot being above the resonance frequency of the antenna and the resonance frequency of the other slot being below the resonance frequency of the antenna.
2 more elements
A method of transceiving circularly polarized signals and linearly polarized signals comprising the steps of:
- defining a cavity in an electrically conductive structure;
- forming two slots in said electrically conductive structure, wherein the two slots each have a different length and each have a different resonance frequency;
- and
- coupling a circuit to said slots, said circuit capable of conducting both said circulary polarized and linearly polarized signals.
1 more element
Dependencies are inferred from the claim text.