Antenna for railway vehicles
Antenna ( 1 ) for railway vehicles comprising: a plurality of photonic band gaps PGB cells ( 2 ), placed adjacent each other and made of a layer of low dielectric properties material placed on a metal ground plane ( 4 ), wherein each photonic band gap cell ( 2 ) form a reflector ( 6 ) of the antenna ( 1 ); a plurality of first metallic bars ( 8 ), placed on top of the PBG cells ( 2 ); a plurality of second metallic bars ( 10 ), each embedded, at least partially, in the thickness of the low dielectric properties material; wherein the second metallic bars ( 10 ) are each roughly perpendicular to the respective reflector ( 6 ).
1. Antenna ( 1 ) for railway vehicles comprising:
a plurality of photonic band gaps PGB cells ( 2 ), placed adjacent each other and made of a layer of low dielectric properties material placed on a metal ground plane ( 4 ), wherein each photonic band gap cell ( 2 ) form a reflector ( 6 ) of the antenna ( 1 );
a plurality of first metallic bars ( 8 ), placed on top of the PBG cells ( 2 );
a plurality of second metallic bars ( 10 ), each embedded, at least partially, in the thickness of the low dielectric properties material;
wherein the second metallic bars ( 10 ) are each roughly perpendicular to the respective reflector ( 6 ).
2. The antenna of claim 1 , wherein the second metallic bars ( 10 ) are each placed between the first metallic bars ( 8 ) and the metal ground plane ( 4 ).
3. The antenna of claim 1 , wherein the antenna ( 1 ) is configured to generate a low frequency wave, notably in a direction (A) perpendicular to the reflectors.
4. The antenna of claim 1 , wherein the first metallic bars ( 8 ) are seven including a first and a second external lateral metallic bars ( 8 a ) placed on a left side with respect to the length of the antenna ( 1 ), near the edge of the antenna ( 1 ), four internal metallic bars placed in a region comprised between the first and second external lateral metallic bars ( 8 a ) comprising two up metallic bars ( 8 b ′) facing the first external lateral metallic bar ( 8 a ′) and two down metallic bars ( 8 b ″) facing the second external lateral metallic bar ( 8 a ″), and a central metallic bar ( 8 c ) placed in a region comprised between the two up metallic bars ( 8 b ′) and the two down metallic bars ( 8 b ″), on a right side with respect to the length of the antenna ( 1 ).
5. The antenna of claim 1 , wherein each first metallic bar ( 8 ) comprises two radiators.
6. The antenna of claim 1 , arranged to operate by transmitting each first metallic bar ( 8 ) in a burst mode transmission round robin.
7. The antenna of claim 1 , wherein each first metallic bar ( 8 ) is arranged to emit a wavelength at 250 MHz.
8. The antenna of claim 7 , arranged to emit in a propagation space a low frequency wavelength of 2.5 MHz.
9. The antenna of claim 1 , wherein the low dielectric properties material comprises Arlon 25N.
10. Railway vehicle ( 100 ) comprising an antenna according to claim 1 .
11. Railway vehicle ( 100 ) according to claim 10 , wherein the antenna is mounted on a roof of the railway vehicle ( 100 ) with the first metallic bars ( 8 ) advantageously facing the direction of the railway vehicle movement.
12. Railway vehicle comprising an antenna according to claim 2 .
13. Railway vehicle comprising an antenna according to claim 3 .
14. Railway vehicle comprising an antenna according to claim 4 .
15. Railway vehicle comprising an antenna according to claim 5 .
16. Railway vehicle comprising an antenna according to claim 6 .
17. Railway vehicle comprising an antenna according to claim 7 .
18. Railway vehicle comprising an antenna according to claim 8 .
19. Railway vehicle comprising an antenna according to claim 9 .
20. Railway vehicle according to claim 12 , wherein the antenna is mounted on a roof of the railway vehicle with the first metallic bars advantageously facing the direction of the railway vehicle movement.