Patch antenna with wire radiation elements for high-precision GNSS applications

Abstract

A right-hand circularly-polarized patch antenna comprising a ground plane and a patch connected to each other with one or more wires for which the wire shape and location of the end points are selected such that they do not cause an antenna mismatch, and the electrical current carried in the wires produces an extra electromagnetic field subtracted from the patch field in the nadir direction.

The invention claimed is: 
     
       1. A single-band circularly-polarized antenna comprising:
 a ground plane; 
 a radiating patch disposed above the ground plane; 
 a dielectric disposed between the ground plane and the radiating patch; 
 a plurality of wires symmetrically oriented about an antenna axis of symmetry orthogonal to the ground plane and passing through a center of the single-band circularly-polarized antenna, each wire having a first endpoint connected to the ground plane and a second endpoint connected to the radiating patch, the first endpoint and the second endpoint being connected by a horizontal wire segment connected between a first vertical wire segment and a second vertical wire segment, the horizontal wire segment being parallel with the ground plane and the radiating patch and positioned above the radiating patch, and the first vertical wire segment and the second vertical wire segment being orthogonal to the ground plane and the radiating patch; and 
 wherein the symmetric orientation of the plurality of wires provides for generation of an electrical current through each horizontal wire segment of each wire of the plurality of wires such that a total antenna field in a nadir direction of the single-band circularly-polarized antenna is reduced. 
 
     
     
       2. The single-band circularly-polarized antenna of  claim 1  wherein the single-band circularly-polarized antenna is a right-hand circularly polarized antenna. 
     
     
       3. The single-band circularly-polarized antenna of  claim 2  wherein the plurality of wires comprises four wires and the respective horizontal wire segment of each wire is straight. 
     
     
       4. The single-band circularly-polarized antenna of  claim 2  wherein the plurality of wires comprises four wires and the respective horizontal wire segment of each wire has at least one bend. 
     
     
       5. The single-band circularly-polarized antenna of  claim 2  wherein at least one horizontal wire segment has a length determined as a function of wavelength. 
     
     
       6. The single-band circularly-polarized antenna of  claim 5  wherein the wavelength is at least one horizontal wire segment has a length equal to a quarter of a wavelength. 
     
     
       7. The single-band circularly-polarized antenna of  claim 2  wherein the radiating patch is excited by an excitation circuit connected to a plurality of excitation pins. 
     
     
       8. The single-band circularly-polarized antenna of  claim 2  wherein the ground plane has a length that is equal to the radiating patch. 
     
     
       9. The single-band circularly-polarized antenna of  claim 2  wherein the respective horizontal wire segments in combination with the ground plane form a transmission line such that the transmission line is connected to the radiating patch. 
     
     
       10. The single-band circularly-polarized antenna of  claim 2  wherein the reduction of the total antenna field in the nadir direction is a function of a variation between a first electromagnetic field associated with the plurality of wires and a second electromagnetic field associated with the radiating patch. 
     
     
       11. A dual-band circularly-polarized antenna comprising:
 a ground plane; 
 a low frequency (LF) radiating patch, the LF radiating patch disposed above the ground plane; 
 a first dielectric disposed between the ground plane and the LF radiating patch; 
 a high frequency (HF) radiating patch, the HF radiating patch disposed above the LF radiating patch; 
 a second dielectric disposed between the HF radiating patch and the LF radiating patch; 
 a plurality of reactive impedance elements symmetrically oriented about an antenna axis of symmetry orthogonal to the ground plane and passing through a center of the dual-band circularly-polarized antenna, the plurality of reactive impedance elements configured to produce a short-circuit condition in a LF band, and substantially open-circuit condition within a HF band; 
 a plurality of wires symmetrically oriented about the antenna axis of symmetry orthogonal to the ground plane and passing through the center of the dual-band circularly-polarized antenna, each wire having a first endpoint connected to a first one of the reactive impedance elements with the first one of the reactive impedance elements connected to the ground plane, and a second endpoint connected to a second one of the reactive impedance elements with the second one of the reactive impedance elements connected to the LF radiating patch, the first endpoint and the second endpoint being connected by a horizontal wire segment connected between a first vertical wire segment and a second vertical wire segment, the horizontal wire segment being parallel with the ground plane and the LF radiating patch and positioned above the LF radiating patch, and the first vertical wire segment and the second vertical wire segment being orthogonal to the ground plane, the LF radiating patch and the HF radiating patch; and 
 wherein the symmetric orientation of the plurality of wires provides for generation of an electrical current through each horizontal wire segment of each wire of the plurality of wires such that a total antenna field in a nadir direction of the dual-band circularly-polarized antenna is reduced. 
 
     
     
       12. The dual-band circularly-polarized antenna of  claim 11  wherein the dual-band circularly-polarized antenna is a right-hand circularly polarized antenna. 
     
     
       13. The dual-band circularly-polarized antenna of  claim 12  wherein the plurality of wires comprises four wires and the respective horizontal wire segment of each wire is straight. 
     
     
       14. The dual-band circularly-polarized antenna of  claim 12  wherein the plurality of wires comprises four wires and the respective horizontal wire segment of each wire has at least one bend. 
     
     
       15. The dual-band circularly-polarized antenna of  claim 12  wherein at least one horizontal wire segment has a length determined as a function of wavelength. 
     
     
       16. The dual-band circularly-polarized antenna of  claim 15  wherein the wavelength is at least one horizontal wire segment has a length equal to a quarter of a wavelength of the LF band. 
     
     
       17. The dual-band circularly-polarized antenna of  claim 12  wherein the respective horizontal wire segments in combination with the ground plane form a respective transmission line, and the respective transmission line is connected to the LF radiating patch. 
     
     
       18. The dual-band circularly-polarized antenna of  claim 17  wherein at least one reactive impedance element of the plurality of reactive impedance elements includes a micro strip line. 
     
     
       19. The dual-band circularly-polarized antenna of  claim 18  wherein the micro strip line and a dielectric substrate located below the ground plane are subject to an electrical short there between. 
     
     
       20. The dual-band circularly-polarized antenna of  claim 12  wherein the ground plane has a length that is equal to the LF radiating patch and the HF radiating patch. 
     
     
       21. The dual-band circularly-polarized antenna of  claim 12  wherein the reduction of the total antenna field in the nadir direction is a function of a variation between a first electromagnetic field associated with the plurality of wires and a second electromagnetic field associated with the LF radiating patch. 
     
     
       22. The dual-band circularly-polarized antenna of  claim 21  where the variation is determined by subtracting the second electromagnetic field from the first electromagnetic field. 
     
     
       23. The single-band circularly-polarized antenna of  claim 10  wherein the variation is determined by subtracting the second electromangeitc field from the first electromagnetic field.