Claims
- 1. A method of producing a circularly polarized wideband traveling wave from a compact, lightweight, planar microstrip antenna for a mobile communications platform, comprising the steps of:forming a microstrip with an upper dielectric layer and a lower dielectric layer; shaping a first conductive patch and a second conductive patch to be circularly curved; disposing said first conductive patch and said second conductive patch on said lower dielectric layer; separating said first conductive patch and said second conductive patch by a gap; disposing a conductive ground plane on a planar surface of said lower dielectric layer; covering said gap by placing a circularly curved coupling patch on said upper dielectric layer; electro-magnetically coupling a single coaxial feed probe to said first patch and said lower dielectric layer in a direction perpendicular to a direction of propagation across said lower dielectric layer; exciting said microstrip to produce a leaky wave radiation; circularly polarizing the leaky wave radiation; the circularly polarizing step further comprising the steps of: producing two perpendicular, radiating fields; and shifting the phase of at least one of the fields until the two fields are 90 degrees out of phase; controlling an antenna radiation level and an input impedance of said antenna by said upper dielectric layer and said lower dielectric layer causing said input impedance to match a leaky wave propagation mode of said leaky wave radiation; positioning said first, second and coupling patches on said layers causing an alteration of a field strength at said single coaxial probe resulting in said field strength matching said input impedance at said single coaxial probe; and aligning said first, second and coupling patches to circularly polarize the leaky wave radiation when a traveling wave propagates along said first, second and coupling patches; wherein the step of producing two perpendicular, radiating fields comprisespropagating a traveling wave from one of the radiating fields along one quarter of a circumference of a circle, resulting in a 6 dB bandwidth of at least 11 per cent.
- 2. The method of producing the circularly polarized wideband traveling wave from the compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited in claim 1, wherein the step of propagating a traveling wave comprises propagating a traveling wave along said first and second conductive patches disposed on said lower dielectric layer and said coupling patch disposed on said upper dielectric layer, wherein the first, second and coupling patches are located along at least a portion of the circumference of the circle.
- 3. The method of producing the circularly polarized wideband traveling wave from the compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited claim 2, wherein the step of shifting the phase comprises propagating the traveling wave along the first, second and coupling patches one quarter of the circumference of the circle, which is a distance of about one quarter of the wavelength of the leaky wave radiation propagating in the antenna.
- 4. The method of producing the circularly polarized wideband traveling wave from the compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited in claim 3, further comprising the steps of:forming said layers with a dielectric constant equal or less than 2.2; and exciting said microstrip by said single coaxial probe to produce said leaky wave radiation in a frequency range given by the formula: fc<f<fcεrεr-1where said εr is a dielectric constant of said lower dielectric layer, said fC is a cutoff frequency and said f is an operating frequency.
- 5. The method of producing the circularly polarized wideband traveling wave from the compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited in claim 3, wherein:said layers having a dielectric constant of about 1.1; and a CP bandwidth of at least 20 per cent.
- 6. The method of producing a circularly polarized wideband traveling wave from a compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited in claim 1, wherein the step of exciting said microstrip to produce leaky wave radiation further comprises the step of preventing and suppressing radiation caused by surface mode excitations.
- 7. The method of producing a circularly polarized wideband traveling wave from a compact, lightweight, planar microstrip antenna for a mobile communications platform, as recited in claim 6, wherein the step of matching the input impedance further comprises the step of varying the widths and the locations of said first, second and conductive patches along the upper and lower dielectric layers of the microstrip until the input impedance of the antenna matches said leaky wave propagation mode of the radiation.
- 8. An article of manufacture for producing a circularly polarized wideband traveling wave for mobile communications platforms, further comprising:a circularly polarized leaky-wave wide band traveling wave formed by: producing leaky wave radiation; and circularly polarizing the leaky wave radiation with a compact, lightweight, planar circularly polarized wideband traveling wave microstrip antenna, further comprising: a microstrip having an upper dielectric layer and a lower dielectric layer; a first conductive patch and a second conductive patch, each being circularly curved and located on said lower dielectric layer, are separated by a gap; a conductive ground plane is disposed on a planar surface of said lower dielectric layer; a coupling patch, being composed of a conductive material, circularly curved and positioned on said upper dielectric layer, covers said gap; a single coaxial feed probe being coupled to said first patch and said lower dielectric layer, said single coaxial probe excites said microstrip to produce a leaky wave radiation; wherein the leaky wave radiation is circularly polarized by: producing two perpendicular, radiating fields; and shifting the phase of at least one of the fields until the two fields are 90 degrees out of phase; said upper dielectric layer and said lower dielectric layer controlling an antenna radiation level and an input impedance of said antenna, causing said input impedance to match a leaky wave propagation mode of said leaky wave radiation; said first, second and coupling patches being positioned on said layers causing an alteration of a field strength at said single coaxial probe resulting in said field strength matching said input impedance at said single coaxial probe; said first, second and coupling patches being configured and aligned to circularly polarize the leaky wave radiation when a traveling wave propagates along said first, second and coupling patches; wherein the two perpendicular, radiating fields are produced by propagating a traveling wave from one of the radiating fields along one quarter of a circumference of a circle, resulting in a 6 dB bandwidth of at least 11 per cent.
- 9. The article of manufacture for producing a circularly polarized wideband traveling wave for mobile communications platforms, as recited in claim 8, wherein the traveling wave propagates along one quarter of the circumference by propagating along said first and second conductive patches disposed on said lower dielectric layer and said coupling patch disposed on said upper dielectric layer, wherein the first, second and coupling patches are located along at least a portion of the circumference of the circle.
- 10. The article of manufacture for producing a circularly polarized wideband traveling wave for mobile communications platforms, as recited in claim 9, wherein the phase is shifted by propagating the traveling wave along the first, second and coupling patches one quarter of the circumference of the circle, which is a distance of approximately one quarter of the wavelength of the leaky wave radiation propagating in the antenna.
- 11. The article of manufacture for producing a circularly polarized, wideband traveling wave for mobile communications platforms, as recited in claim 10, further comprising said upper and lower dielectric layers having a dielectric constant equal or less than 2.2.
- 12. The article of manufacture for producing a circularly polarized wideband traveling wave for mobile communications platforms, as recited in claim 10, further comprising:said upper and lower dielectric layers having a dielectric constant of about 1.1; and a CP bandwidth of at least 20 per cent.
- 13. The article of manufacture for producing a circularly polarized wideband traveling wave for mobile communications platforms, as recited in claim 8, wherein the leaky wave radiation is produced by:matching the input impedance of the antenna to the leaky wave propagation mode of the radiation; and preventing and suppressing radiation caused by surface mode excitations.
- 14. A compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, comprising:a microstrip having an upper dielectric layer and a lower dielectric layer, said upper and lower dielectric layers being rectangular; a first conductive patch and a second conductive patch, each being circularly curved and located on said lower dielectric layer, are separated by a gap; a conductive ground plane is disposed on a planar surface of said lower dielectric layer; a coupling patch, being composed of a conductive material, circularly curved and positioned on said upper dielectric layer, covers said gap; a single coaxial feed probe being coupled to said first patch and said lower dielectric layer, said single coaxial probe excites said microstrip to produce a leaky wave radiation; said upper dielectric layer and said lower dielectric layer control an antenna radiation level and an input impedance of said antenna, causing said input impedance to match a leaky wave propagation mode of said leaky wave radiation; said first, second and coupling patches being positioned on said layers cause an alteration of a field strength at said single coaxial probe resulting in said field strength matching said input impedance at said single coaxial probe; and said first, second and coupling patches being configured and aligned to circularly polarize the leaky wave radiation when a traveling wave propagates along said first, second and coupling patches resulting in a 6 dB bandwidth of at least 11 per cent.
- 15. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 14, further comprising the single coaxial feed probe being electro-magnetically coupled to said first patch in a direction perpendicular to a direction of propagation across said lower dielectric layer.
- 16. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 15, further comprising:said first conductive patch and said second conductive patch provide a first radiating source; said coupling patch provides a second radiating source; wherein the two sources produce perpendicular fields of approximately equal magnitudes; and said single coaxial probe excites said microstrip to produce said leaky wave radiation in a frequency range given by the formula: fc<f<fcεrεr-1where said εr is a dielectric constant of said lower dielectric layer, said fC is a cutoff frequency and said f is an operating frequency.
- 17. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 16, wherein the fields of the two radiating sources are 90 degrees out of phase.
- 18. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 17, further comprising:the two radiating sources being configured and aligned to circularly polarize the leaky wave radiation; the fields produced by the two radiating sources become perpendicular to each other by propagating a traveling wave from the first radiating source along the circularly curved shape of the first, second and coupling patches by 90 degrees of the circumference of a circle.
- 19. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 18, wherein a distance of 90 degrees along the circularly curved shape of the patches equals approximately one quarter of the wavelength of the radiation while the radiation is propagating in the antenna, so that the phase of the first radiating source is shifted by 90 degrees.
- 20. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 19, further comprising:said first patch, being circularly curved and having a first radius; said second patch, being circularly curved and having a second radius which is larger than the first radius, so that said gap is formed on the surface of the lower dielectric layer in between the first and second conductive patches; said coupling patch, being circularly curved and located on the upper dielectric layer, above the gap on the lower dielectric layer, so that the coupling patch is electro-magnetically coupled to the lower dielectric layer; wherein a difference between an impedance of a plurality of surface modes and a leaky wave impedance suppresses said plurality of surface modes.
- 21. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 20, further comprising:said upper and lower dielectric layers having a dielectric constant of about 1.1; and a CP bandwidth of at least 20 per cent.
- 22. The compact, lightweight, planar circularly polarized leaky-wave wideband traveling wave microstrip antenna for mobile communications platforms, as recited in claim 20, wherein the circular shape of the upper and lower dielectric layers is at least a quarter circle.
CONTINUATION-IN-PART
This application is a Continuation-In-Part of U.S. Patent Office application Ser. No. 09/204,045, entitled “Circularly Polarized Traveling-Wave Microstrip Antenna,” which was filed on Dec. 2, 1998, by the same inventors herein, now abandoned. This Continuation-In-Part is being filed under 35 USC §120 and 37 CFR §1.53 and priority from that application is claimed.
GOVERNMENT INTEREST
The invention described herein may be manufactured, used, imported, sold, and licensed by or for the Government of The United States of America without the payment to us of any royalty thereon.
US Referenced Citations (3)
Continuation in Parts (1)
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Number |
Date |
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Parent |
09/204045 |
Dec 1998 |
US |
Child |
09/688419 |
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US |