Vehicle antenna with shorted conductive structure around its radiator
A vehicle antenna ( 20 ) comprising: a radiator ( 24 ) configured to extend from a ground plane ( 26 ); a feed point ( 28 ); a conductive structure ( 30 ) around a portion ( 240 ) of the radiator, the portion being distal from the ground plane; an electrical gap ( 34 ) between the conductive structure and the portion of the radiator; and a shorting arrangement ( 32 ) configured to electrically connect the conductive structure to ground.
1 . A vehicle antenna comprising:
a plurality of radiators;
each radiator configured to extend from a respective ground plane;
each radiator comprising:
a feed point;
a conductive structure having a first radial thickness and being around a portion of the radiator, the portion being distal from the respective ground plane;
an electrical gap between the conductive structure and the portion of the radiator, the electrical gap having a second radial thickness being the same or greater than the first radial thickness; and
a shorting arrangement configured to electrically connect the conductive structure to the respective ground plane,
wherein the radiator is an inverted cone radiator comprising a hollow conical shape having a surface of revolution and being open at a base of the inverted cone radiator.
2 . The vehicle antenna of claim 1 , wherein the ground planes are a part of a vehicle body structure.
3 . The vehicle antenna of claim 2 , wherein the vehicle antenna is configured to be received at a roof cavity of the vehicle body structure.
4 . The vehicle antenna of claim 1 , wherein the radiator, the conductive structure and the electrical gap are configured to promote an omnidirectional radiation pattern.
5 . The vehicle antenna of claim 1 , wherein the radiator and the shorting arrangement are configured to extend perpendicularly from the respective ground planes.
6 . The vehicle antenna of claim 1 , wherein the conductive structure is configured as a capacitance hat.
7 . The vehicle antenna of claim 1 , wherein the conductive structure is ring-shaped.
8 . The vehicle antenna of claim 1 , wherein the portion of the radiator is a distal end of the radiator, and wherein the conductive structure is approximately coplanar with the distal end of the radiator.
9 . The vehicle antenna of claim 1 , comprising dielectric material defining the electrical gap.
10 . The vehicle antenna of claim 1 , wherein the shorting arrangement comprises one or more lines.
11 . The vehicle antenna of claim 1 , wherein the shorting arrangement is configured to electrically connect the conductive structure to the respective ground planes.
12 . A vehicle antenna apparatus comprising the vehicle antenna of claim 1 .
13 . The vehicle antenna apparatus of claim 12 , wherein the ground planes comprises an aperture through which the radiator electrically connects to the feed point.
14 . The vehicle antenna apparatus of claim 12 , wherein the ground planes are substantially coplanar with a proximal end of the radiator, proximal to the feed point.
15 . The vehicle antenna apparatus of claim 12 , wherein the ground planes comprises a conductive sheet configured to be secured to a vehicle body structure.
16 . A vehicle comprising the vehicle antenna of claim 1 .
17 . A vehicle comprising the vehicle antenna apparatus of claim 12 .
18 . The vehicle antenna of claim 9 , wherein the dielectric material is a substrate or is on a substrate, and wherein the conductive structure is layered on the substrate.
19 . The vehicle antenna of claim 10 , wherein the shorting arrangement comprises a plurality of lines approximately equispaced around a periphery of the radiator.
20 . The vehicle antenna apparatus of claim 12 , wherein the ground planes have a larger surface area than the conductive structure.