Method and system for improving isolation in radio-frequency antennas
First Claim
1. An antenna structure (1) comprising:
- a ground plane (10) having a first section (12) and a second section (14) galvanically connected to the first section (12); and
an antenna system (22, 24) operable in a frequency band and disposed over the ground plane (10), the antenna system comprising a receive antenna (22) and a transmit antenna (24), wherein the receive antenna (22) comprises a first radiating element (30) disposed over the first section (12) of the ground plane (10), and a first grounding strip (34) for grounding the first radiating element (30) to the first section (12) of the ground plane (10); and
the transmit antenna (24) comprises a second radiating element (40) disposed over the second section (14) of the ground plane (10), and a second grounding strip (44) for grounding the second radiating element (40) to the second section (14) of the ground plane (10), characterized by a slot (20) provided between the first section (12) and the second section (14) of the ground plane (10) for improving isolation between the receive antenna and the transmit antenna, wherein the slot has an effective length (L) substantially equal to a quarter wavelength of the frequency band.
2 Assignments
0 Petitions
Accused Products
Abstract
In an antenna structure having a transmit antenna disposed over a first section of a ground plane and a receive antenna disposed over a second section of the ground plane, a cut is provided between the first and second sections of the ground plan The length of the cut is substantially equal to one quarter-wavelength of the operating frequency band of transmit/receive antenna pair so as to provide isolation between the transmit antenna and the receive antenna. If the antenna structure also has a transceiver antenna operated in a further frequency band disposed over the same ground plane and straddling over the first section and the second section, a switch is provided over the cut. The switch is operating in a closed position when the transceiver antenna in the further frequency band is used, and in an open position when the transmit/receiver antenna pair is used.
113 Citations
21 Claims
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1. An antenna structure (1) comprising:
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a ground plane (10) having a first section (12) and a second section (14) galvanically connected to the first section (12); and
an antenna system (22, 24) operable in a frequency band and disposed over the ground plane (10), the antenna system comprising a receive antenna (22) and a transmit antenna (24), wherein the receive antenna (22) comprises a first radiating element (30) disposed over the first section (12) of the ground plane (10), and a first grounding strip (34) for grounding the first radiating element (30) to the first section (12) of the ground plane (10); and
the transmit antenna (24) comprises a second radiating element (40) disposed over the second section (14) of the ground plane (10), and a second grounding strip (44) for grounding the second radiating element (40) to the second section (14) of the ground plane (10), characterized by a slot (20) provided between the first section (12) and the second section (14) of the ground plane (10) for improving isolation between the receive antenna and the transmit antenna, wherein the slot has an effective length (L) substantially equal to a quarter wavelength of the frequency band. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
a switching means (60) disposed over the slot, wherein the switching means is operable in a closed position, for electrically connecting the first section (12) and the second section (14) when the antenna structure (1) is operating in the further frequency band, and in an open position, for keeping the first section (12) and the second section (14) electrically separated over the slot, when the antenna structure (1) is operating in the frequency band. -
5. The antenna structure of claim 4, further comprising a further antenna system (122, 124) operable in a third frequency band different from the frequency band, the further antenna system comprising a further receive antenna (122) and a further transmit antenna (124), wherein
the further receive antenna (122) comprises a fourth radiating element (130) disposed over the first section of the ground plane, and a fourth grounding strip (134) for grounding the fourth radiating element to first section of the ground plane; - and
the further transmit antenna (124) comprises a fifth radiating element (140) disposed over the second section of the ground plane, and a fifth grounding strip (144) for grounding the fifth radiating element to the second section of the ground plane, characterized in that the switching means (60) is also operating in the open position when the antenna structure is operating in the third frequency band, and further characterized by a further switching means (64) disposed over the slot, wherein the further switching means is operable in an open position for retaining the effective length (L) of the slot when the antenna structure is operating in the frequency band, and in a closed position for realizing an effective length (L′
) of the slot substantially equal to a quarter wavelength of the third frequency band when the antenna structure is operating in the third frequency band.
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6. The antenna structure of claim 4, further comprising a further antenna system (122, 124) operable in a third frequency band different from the frequency band, the further antenna system comprising a further receive antenna (122) and a further transmit antenna (124), wherein
the further receive antenna (122) comprises a fourth radiating element (130) disposed over the first section of the ground plane, and a fourth grounding strip (134) for grounding the fourth radiating element to first section of the ground plane; - and
the further transmit antenna (124) comprises a fifth radiating element (140) disposed over the second section of the ground plane, and a fifth grounding strip (144) for grounding the fifth radiating element to the second section of the ground plane, characterized in that the switching means (60) is also operating in the open position when the antenna structure is operating in the third frequency band, and further characterized by a further switching means (64) disposed over the slot, wherein the further switching means is operable in a closed position for retaining the effective length (L) of the slot when the antenna structure is operating in the frequency band, and in an open position for realizing an effective length (L′
) of the slot substantially equal to a quarter wavelength of the third frequency band when the antenna structure is operating in the third frequency band.
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7. The antenna structure of claim 1, further comprising a further antenna system (122, 124) operable in a further frequency band different from the frequency band, the further antenna system (122, 124) comprising a further receive antenna (122) and a further transmit antenna (124), wherein
the further receive antenna (122) comprises a third radiating element (130) disposed over the first section of the ground plane, and a third grounding strip (134) for grounding the third radiating element to the first section of the ground plane; - and
the further transmit antenna (124) comprises a fourth radiating element (140) disposed over the second section of the ground plane, and a fourth grounding strip (144) for grounding the fourth radiating element to the second section of the ground plane, characterized by a switching means (64) disposed over the slot, wherein the switching means is operable in an open position to retain the effective length (L) of the slot when the antenna structure is operating in the frequency band, and in a closed position to realize an effective length (L′
) of the slot substantially equal to a quarter wavelength of the further frequency band when the antenna structure is operating in the further frequency band.
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8. The antenna structure of claim 1, further comprising a further antenna system (122, 124) operable in a further frequency band different from the frequency band, the further antenna system (122, 124) comprising a further receive antenna (122) and a further transmit antenna (124), wherein
the further receive antenna (122) comprises a third radiating element (130) disposed over the first section of the ground plane, and a third grounding strip (134) for grounding the third radiating element to the first section of the ground plane; - and
the further transmit antenna (124) comprises a fourth radiating element (140) disposed over the second section of the ground plane, and a fourth grounding strip (144) for grounding the fourth radiating element to the second section of the ground plane, characterized by a switching means (62) disposed over the slot, wherein the switching means is operable in a closed position to retain the effective length (L) of the slot when the antenna structure is operating in the frequency band, and in an open position to realize an effective length (L′
) of the slot substantially equal to a quarter wavelength of the further frequency band when the antenna structure is operating in the further frequency band.
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9. A method of improving isolation in an antenna structure (1), wherein the antenna structure (1) comprises:
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a ground plane (10) having a first section (12) and a second section (14) galvanically connected (16) to the first section (12), and an antenna system (22, 24) operable in a frequency band disposed over the ground plane (10), the antenna system comprising a receive antenna (22) and a transmit antenna (24), wherein the receive antenna (22) comprises a first radiating element (30) disposed over the first section (12) of the ground plane (10), and a first grounding strip (34) for grounding the first radiating element (30) to the first section of the ground plane (10); and
the transmit antenna (24) comprises a second radiating element (40) disposed over the second section (14) of the ground plane (10), and a second grounding strip (44) for grounding the second radiating element (40) to the second section of the ground plane (10), said method characterized by providing a slot (20) between the first section (12) and the second section (14) of the ground plane for improving isolation between the transmit antenna and the receive antenna, wherein the slot has an effective length (L) substantially equal to a quarter wavelength of the frequency band. - View Dependent Claims (10)
providing a switching means (60) over the slot, wherein the switching means is operable in a closed position, for electrically connecting the first section (12) and the second section (14) when the antenna structure (1) is operating in the further frequency band, and in an open position, for keeping the first section (12) and the second section (14) electrically separated over the slot (20), when the antenna structure (1) is operating in the frequency band.
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11. A mobile terminal (200) having an improved antenna structure (1) for receiving and transmitting information in a frequency band, the antenna structure (1) comprising:
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a ground plane (10) having a first section (12) and a second section (14) galvanically connected (16) to the first section (12), and an antenna system (22, 24) disposed over the ground plane (10), the antenna system (22, 24) comprising a receive antenna (22) and a transmit antenna (24), wherein the receive antenna (22) comprises a first radiating element (30) disposed over the first section (12) of the ground plane (10), and a first grounding strip (34) for grounding the first radiating element (30) to the first ground plane (10); and
the transmit antenna (24) comprises a second radiating element (40) disposed over the second section (14) of the ground plane (10), and a second grounding strip (44) for grounding the second radiating element (40) to the second section of the ground plane (10), characterized by a slot (20) provided between the first section (12) and the second section (14) of the ground plane (10) for improving isolation between the receive antenna and the transmit antenna, wherein the slot has an effective length (L) substantially equal to one quarter wavelength of the frequency band. - View Dependent Claims (12)
a switching means (60) disposed over the slot, wherein the switching means is operable in a closed position, for electrically connecting the first section (12) and the second section (14) when the antenna structure is operating in the further frequency band, and in an open position, for keeping the first section (12) and the second section (14) electrically separated over the slot (20), when the antenna structure is operating in the frequency band.
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13. An antenna structure (2) comprising a first antenna (70, 80) and a second antenna (40), each antenna having a radiating element, a feed line and a grounding strip coupling to the radiating element to a ground plane, wherein one of the first and second antennas is used for transmission and the other is used for reception, characterized in that
the radiating element (78, 88, 90) has a slot (76, 86) provided thereon for effectively separating the feed line (72, 82) and the grounding strip (74, 84) of the first antenna (70, 80) by a distance substantially equal to one half wavelength of a resonant frequency of the radiating element (78, 88, 90) of the first antenna.
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20. A method of improving isolation in antenna structure (2), wherein the antenna structure comprises a first antenna (70, 80) and a second antenna (40), each antenna having a radiating element, a feed line and a grounding strip coupling to the radiating element to a ground plane, wherein one of the first and second antennas is used for transmission and the other is used for reception, characterized by
providing a slot (76, 86) on the radiating element (78, 88, 90) for effectively separating the feed line (72, 82) and the grounding strip (74, 84) of the first antenna (70, 80) by a distance substantially equal to one half wavelength of a resonant frequency of the radiating element (78, 88, 90) of the first antenna.
Specification