Antenna arrangement
View Patent ↗An antenna arrangement operable at a first resonant frequency f having a corresponding resonant wavelength λ the antenna arrangement comprising: an antenna comprising a feed; a ground plane coupled to the antenna comprising a first region and a second region; and a grounded conductive structure coupled to the first region of the ground plane, wherein the second region of the ground plane is configured such that, at the first resonant frequency f the current flows predominantly in the grounded conductive structure compared to the second region of the ground plane.
1. An antenna arrangement comprising:
an antenna comprising a feed;
a ground plane coupled to the antenna comprising a first region and a second region; and
a grounded conductive structure coupled to the first region of the ground plane, wherein
the second region of the ground plane is configured such that at a first resonant frequency f and a corresponding resonant wavelength λ, the current flows predominantly in the grounded conductive structure compared to the second region of the ground plane; and wherein
the grounded conductive structure comprises a variable tuning device configured to tune the electrical length of the grounded conductive structure so that the grounded conductive structure is resonant at a frequency other than the first resonant frequency f.
2. An antenna arrangement as claimed in claim 1 wherein the grounded conductive structure is configured so that a resonating portion comprising, the antenna, the first region of the ground plane and the grounded conductive structure has an electrical length of
n
λ
m
where n and m are integers.
3. An antenna arrangement as claimed in claim 2 wherein m is 2.
4. An antenna arrangement as claimed in claim 2 wherein the grounded conductive structure comprises a conductive strip configured so that the structure comprising the first region of the ground plane and the conductive strip have an electrical length of
n
λ
m
.
5. An antenna arrangement as claimed in claim 1 wherein the grounded conductive structure is coupled to the first region of the ground plane close to the connection between the antenna and the ground plane.
6. An antenna arrangement as claimed in claim 1 wherein the second region of the ground plane comprises a structure configured so that the impedance of the second region of ground plane at the first resonant frequency f is significantly different to the impedance of the grounded conductive structure.
7. An antenna arrangement as claimed in claim 6 wherein the structure is configured to increase the impedance of the second region of ground plane at the first resonant frequency f.
8. An antenna arrangement as claimed in claim 6 wherein the structure comprises slots within the ground plane.
9. An antenna arrangement as claimed in claim 6 wherein the structure comprises a tuning circuit.
10. An antenna arrangement as claimed in claim 6 wherein the structure comprises a wave trap.
11. An antenna arrangement as claimed in claim 1 wherein the grounded conductive structure comprises a connection to another component of an apparatus within which the antenna arrangement is housed.
12. An antenna arrangement as claimed in claim 1 wherein the ground plane comprises a printed wiring board.
13. An apparatus comprising an antenna arrangement as claimed in claim 1 .
14. An antenna arrangement as claimed in claim 1 , wherein the tuning device is configured to enable the grounded conductive structure to be disconnected from the antenna arrangement.
15. An antenna arrangement comprising:
an antenna comprising a feed;
a ground plane coupled to the antenna comprising a first region and a second region; and
a grounded conductive structure coupled to the first region of the ground plane, wherein
the second region of the ground plane is configured such that at a first resonant frequency f and a corresponding resonant wavelength λ the antenna couples predominantly to the grounded conductive structure; and wherein
the grounded conductive structure comprises a variable tuning device configured to tune the electrical length of the grounded conductive structure so that the grounded conductive structure is resonant at a frequency other than the first resonant frequency f.
16. An antenna arrangement as claimed in claim 15 wherein the grounded conductive structure is configured so that a resonating portion comprising, the antenna, the first region of the ground plane and the grounded conductive structure has an electrical length of
n
λ
m
where n and m are integers.
17. An antenna arrangement as claimed in claim 16 wherein m is 2.
18. A method comprising;
providing an antenna arrangement operable at a first resonant frequency f having a corresponding resonant wavelength, the antenna arrangement comprising: an antenna comprising a feed; a ground plane comprising a first region and a second region coupled to the antenna; and a grounded conductive structure coupled to the first region of the ground plane, the grounded conductive structure comprising a variable tuning device configured to tune the electrical length of the grounded conductive structure so that the grounded conductive structure is resonant at a frequency other than the first resonant frequency f;
receiving, by the antenna arrangement, a signal at the first resonant frequency f and
coupling the antenna predominantly to the grounded conductive structure.
19. A method as claimed in claim 18 comprising configuring the grounded conductive structure so that a resonating portion comprising, the antenna, the first region of the ground plane and the grounded conductive structure have an electrical length of
n
λ
m
where n and m are integers.