Wideband antenna
View Patent ↗A vehicle window assembly. The window assembly includes a frame having an inner metal edge and a window pane fixed to the frame. The window pane includes an inner glass ply, an outer glass ply, an interlayer between the inner glass ply and the outer glass ply, and an electro-conductive coating located on a surface of the outer glass ply, wherein the electro-conductive coating has an outer peripheral edge spaced from the inner metal edge of the frame to define an antenna slot. The window assembly also includes an antenna feed structure electrically connected to the outer peripheral edge of the electro-conductive coating and a capacitive coupling strip located on the inner glass ply and overlapping the outer peripheral edge of the electro-conductive coating proximate the antenna feed structure, wherein the coupling strip couples a wide bandwidth radio frequency signal into and out of the antenna slot.
1. A window assembly for use in connection with a window frame having a metal edge, said window assembly cooperating with said window frame to define at least one antenna that is electrically connectable to an electrical feed, said window assembly comprising:
at least one ply;
an electro-conductive coating that is located on a surface of said at least one glass ply, said electro-conductive coating having a peripheral edge wherein, at times when said window assembly is installed in said window frame, at least a first portion of the peripheral edge is spaced away from the metal edge of the window frame to define a slot antenna between the first portion of said peripheral edge and the metal edge of said window frame;
an antenna feed structure that is electrically connected to the first portion of the peripheral edge of the electro-conductive coating; and
a coupling strip for electrically connecting said antenna feed structure and the electrical feed, said coupling strip having a coupling element that is located opposite from at least a portion of the antenna feed structure said coupling element being positioned with respect to the first portion of the peripheral edge of the electro-conductive coating to match the impedance of said antenna with respect to the impedance of the electrical feed, said coupling strip also having an electrical conductor that is connected to said coupling element and that is electrically connectable to the electrical feed.
2. The window assembly as claimed in claim 1 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz.
3. The window assembly as claimed in claim 1 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz and 470 MHz to 860 MHz.
4. The window assembly as claimed in claim 1 , wherein the coupling strip is bifurcated into a first part and a second part, said coupling strip further comprising an inductor that is disposed between the first part of the coupling strip and the second part of the coupling strip.
5. The window assembly as claimed in claim 4 , wherein the inductor is sized such that an impedance of the slot antenna is matched to an impedance of a transmission line that is in electrical communication with the antenna feed structure.
6. The window assembly as claimed in claim 1 , wherein the antenna feed structure is located in a dark paint band that is located on a peripheral area of the window assembly.
7. The window assembly as claimed in claim 1 , wherein the width of the antenna slot is sized such that a capacitive effect across the antenna slot is substantially negligible for at least one operation frequency.
8. The window assembly as claimed in claim 7 , wherein the width of the antenna slot is greater than 10 mm.
9. The window assembly as claimed in 1 , wherein a total length of the antenna slot is one wavelength for an annular slot antenna and one-half wavelength for a non-annular slot antenna, at the fundamental excitation mode.
10. The vehicle window assembly as claimed in 1 , wherein the antenna feed structure is capacitively coupled to the slot antenna.
11. The window assembly as claimed in claim 1 , wherein the interlayer comprises plastic.
12. The window assembly as claimed in claim 1 , wherein the electro-conductive coating is substantially transparent.
13. The window assembly of claim 1 wherein the length of the first portion of said peripheral edge of said electro-conductive coating determines the effective electrical length of said slot antenna.
14. The window assembly of claim 13 wherein the first portion of said peripheral edge includes at least one slit in the peripheral edge of said electro-conductive coating, said at least one slit increasing the effective electrical length of said slot antenna to tune said slot antenna to a predetermined resonant frequency.
15. The window assembly of claim 14 wherein the peripheral edge of said electro-conductive coating includes more than one slit.
16. A window assembly for use in connection with a window frame having a metal edge, said window assembly cooperating with said window frame to define at least one antenna that is electrically connectable to an electrical feed, said window assembly comprising:
at least a first ply;
an electro-conductive coating that is located on a surface of said first ply, said electro-conductive coating having a peripheral edge wherein, at times when said window assembly is installed in said frame, at least a first portion of the peripheral edge is spaced away from the metal edge of the frame to define a slot antenna between the first portion of said peripheral edge and the metal edge of said frame, and wherein at least a second portion of the peripheral edge of said electro-conductive coating overlaps the metal edge of said frame, said second portion of said peripheral edge defining an antenna feeding area within said electro-conductive coating; and
a coupling strip for electrically connecting said antenna feeding area and the electrical feed, said coupling strip having a coupling element that is located opposite from the antenna feeding area of the electro-conductive coating, said coupling strip also having an electrical conductor that is connected to said coupling element and that is electrically connectable to the electrical feed.
17. The window assembly as claimed in claim 16 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz.
18. The window assembly as claimed in claim 16 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz and 470 MHz to 860 MHz.
19. The window assembly as claimed in claim 16 , wherein the coupling strip is bifurcated into a first part and a second part, said coupling strip further comprising an inductor that is disposed between the first part of the coupling strip and the second part of the coupling strip.
20. The window assembly as claimed in claim 19 , wherein the inductor is sized such that an impedance of the slot antenna is matched to an impedance of a transmission line that is in electrical communication with the antenna feeding area.
21. The window assembly as claimed in claim 16 , wherein the antenna feeding area is located in a dark paint band that is located on a peripheral area of the window assembly.
22. The window assembly as claimed in claim 16 , wherein the width of the antenna slot is sized such that a capacitive effect across the antenna slot is substantially negligible for at least one operation frequency.
23. The window assembly as claimed in claim 22 , wherein the width of the antenna slot is greater than 10 mm.
24. The window assembly as claimed in claim 16 , wherein a total length of the antenna slot is one wavelength for an annular slot antenna and one-half wavelength for a non-annular slot antenna, at the fundamental excitation mode.
25. The window assembly as claimed in claim 16 , wherein the antenna feeding area is capacitively coupled to the slot antenna.
26. The window assembly as claimed in claim 16 , wherein the interlayer comprises plastic.
27. The window assembly as claimed in claim 16 , wherein the electro-conductive coating is substantially transparent.
28. The window assembly of claim 16 wherein said coupling element is located with respect to said antenna feeding area to tune the impedance of said slot antenna with respect to the impedance of said electrical feed.
29. The window assembly of claim 28 wherein the coupling element of said coupling strip is comprised of a first part and a second part and wherein the coupling element further includes an inductor section that electrically connects said first part and said second part.
30. The window assembly of claim 29 wherein said inductor section partially offsets the capacitance effect of said slot antenna.
31. The window assembly of claim 29 wherein the effective electrical length of the slot corresponds to a wavelength at resonant frequency in the ultra-high frequency band.
32. The window assembly of claim 29 wherein the effective electrical length of the slot antenna corresponds to a wavelength at a frequency in the range of 470 MHz to 860 MHz.
33. The window assembly of claim 29 wherein said first and second parts of said coupling element are positioned to tune the impedance of the slot antenna with respect to the impedance of said electrical feed.
34. The window assembly of claim 29 wherein said first part of said coupling element is positioned with respect to said antenna feed area to tune impedance in the UHF band.
35. A window assembly for use in connection with a window frame having a metal edge, said window assembly cooperating with said window frame to define at least one antenna that is electrically connectable to an electrical feed, said window assembly comprising:
a transparent ply;
an interlayer that faces one side of said transparent ply;
an electro-conductive coating that is located on a surface of one of said transparent ply and said interlayer, said electro-conductive coating having a peripheral edge wherein, at times when said window assembly is installed in said window frame, at least a first portion of the peripheral edge is spaced away from the metal edge of the window frame to define a slot antenna between the first portion of said peripheral edge and the metal edge of said window frame, and wherein at least a second portion of the peripheral edge of said electro-conductive coating overlaps the metal edge of said window frame, said second portion of said peripheral edge defining an antenna feeding area within said electro-conductive coating; and
a coupling strip for electrically connecting said antenna feeding area and the electrical feed, said coupling strip having a coupling element that is located on one of said inner transparent ply and said interlayer at a position that is opposite from the antenna feeding area of the electro-conductive coating, said coupling strip also having a foil that is electrically connected to said coupling element and that is electrically connectable to the electrical feed.
36. The window assembly as claimed in claim 35 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz.
37. The window assembly as claimed in claim 35 , wherein said coupling strip matches the impedance of the slot antenna to the impedance of the electrical feed over a frequency bandwidth of from approximately 47 MHz to 240 MHz and 470 MHz to 860 MHz.
38. The window assembly as claimed in claim 35 , wherein the coupling strip is bifurcated into a first part and a second part, said coupling strip further comprising an inductor that is disposed between the first part of the coupling strip and the second part of the coupling strip.
39. The window assembly as claimed in claim 38 , wherein the inductor is sized such that an impedance of the slot antenna is matched to an impedance of a transmission line that is in communication with the antenna feeding area.
40. The window assembly as claimed in claim 35 , wherein the antenna feeding area is located in a dark paint band that is located on a peripheral area of the window assembly.
41. The window assembly as claimed in claim 35 , wherein the width of the antenna slot is sized such that a capacitive effect across the antenna slot is substantially negligible for at least one operation frequency.
42. The window assembly as claimed in claim 41 , wherein the width of the antenna slot is greater than 10 mm.
43. The window assembly as claimed in claim 35 , wherein a total length of the antenna slot is one wavelength for an annular slot antenna and one-half wavelength for a non-annular slot antenna, at the fundamental excitation mode.
44. The window assembly as claimed in claim 35 , wherein the antenna feeding area is capacitively coupled to the slot antenna.
45. The window assembly as claimed in claim 35 , wherein the interlayer comprises plastic.
46. The window assembly as claimed in claim 35 , wherein the electro-conductive coating is substantially transparent.