Vehicular multiband antenna
View Patent ↗A coaxial antenna is implemented that combines a VHF and UHF antenna on a common radiating element. The antenna may further include a satellite antenna that, together with the VHF/UHF antenna fits into a whip antenna footprint. The antenna incorporates chokes that may be implemented using meanderline techniques.
1. A coaxial antenna capable of operating in at least two different frequency ranges, comprising:
radiating elements capable of operating in a first frequency range of interest;
chokes that limit the operating efficiency of at least portions of the radiating elements at the second frequency range;
a sleeve coupled to the radiating elements; and
at least two matching networks, a first one of the matching network coupled between the sleeve and a ground potential and the second one of the matching networks coupled to an antenna feed capable of coupling signals at the first and second frequency ranges to the radiating elements;
wherein the choked portions of the radiating elements are not capable of efficient operation at the second frequency range of interest; and
wherein at least one choke is implemented as a meanderline.
2. The antenna according to claim 1 , wherein the meanderline is implemented using at least two layers of a meanderline.
3. The antenna according to claim 1 , wherein the meanderline is implemented using at least four layers of a meanderline.
4. The antenna according to claim 2 , wherein the meanderline is manufactured on a printed circuit board.
5. The antenna according to claim 1 , wherein the meanderline is self shielding.
6. The antenna according to claim 1 , wherein the meanderline is not self shielding.
7. The antenna according to claim 1 , wherein the radiating elements are supplied using a coaxial cable and a reverse excitation feed.
8. The coaxial antenna according to claim 1 , wherein the first frequency range is lower than the second frequency range.
9. The coaxial antenna according to claim 1 , wherein the first frequency range is higher than the second frequency range.
10. The coaxial antenna according to claim 1 , wherein the antenna is capable of use for at least one of transmitting and receiving at each of the frequency ranges.
11. The coaxial antenna according to claim 1 , wherein the communication with the antenna at the first and second frequency ranges occurs through a common conductor.
12. The coaxial antenna according to claim 11 , wherein the common conductor forms at least part of the radiating elements capable of operating at the first and second frequency ranges.
13. The coaxial antenna according to claim 11 , wherein first and second frequency ranges comprise frequency ranges in the UHF and VHF frequency bands, respectively.
14. The coaxial antenna according to claim 11 , wherein the common conductor is a shielded conductor.
15. The coaxial antenna according to claim 11 , wherein the common conductor is a coaxial cable.
16. The coaxial antenna according to claim 11 ,
further comprising a second conductor capable of carrying a third frequency range; and
wherein the antenna includes a base end and a top end, the common conductor and second conductor enter the base and the second conductor is coupled to an antenna element at the top end of the antenna.
17. The coaxial antenna according to claim 16 , wherein the third frequency range is associated with the L band frequency range.
18. The coaxial antenna according to claim 16 , wherein the antenna element at the top comprises a satellite antenna.
19. A coaxial antenna capable of operating at in at least two different frequency ranges, comprising:
radiating elements capable of operating in a first frequency range of interest;
chokes that limit the operating efficiency of at least portions of the radiating elements at the second frequency range;
a sleeve coupled to the radiating elements;
at least two matching networks, a first one of the matching network coupled between the sleeve and a ground potential and the second one of the matching networks coupled to an antenna feed capable of coupling signals at the first and second frequency ranges to the radiating elements; and
a common conductor coupled to the antenna feed having a reverse excitation coupling; and
wherein the communication with the antenna at the first and second frequency ranges occurs through the common conductor, wherein the choked portions of the radiating elements are not capable of efficient operation at the second frequency range of interest, and wherein at least one choke is implemented as a meanderline.
20. The antenna according to claim 19 , wherein the meanderline is implemented as at least of the following: a multi-layered meanderline, a printed circuit board, a self shielded meanderline.
21. The antenna according to claim 19 , wherein the first and second frequency ranges comprise frequency ranges in the UHF and VHF frequency bands, respectively.
22. The coaxial antenna according to claim 21 ,
further comprising a second conductor capable of carrying a third frequency range; and
wherein the antenna includes a base end and a top end, the common conductor and second conductor enter the base and the second conductor is coupled to an antenna element at the top end of the antenna.
23. The coaxial antenna according to claim 22 , wherein the third frequency range is associated with the L band frequency range.