Embodiments of the present invention relate to an antenna arrangement, a method for manufacturing an antenna arrangement and a printed wiring board for use in an antenna arrangement.
Radio communication is now commonly employed in many electronic apparatus such as wireless local area network nodes, Bluetooth network nodes, cellular network nodes, radio frequency identification devices etc.
There are often constraints imposed upon the design of such apparatus such as size constraints e.g. the size of a printed wiring board (PWB) or functionality constraints e.g. the radio frequency band (or bands) at which the device should operate.
It can be difficult to tune the performance of a radio communication device while respecting imposed constraints.
According to various embodiments of the invention there is provided an antenna arrangement comprising: a conductive ground element having a first end and a second end; an antenna element at a first end; a first conductive part extending from the second end of the conductive ground element and a second conductive part extending from the second end of the conductive ground element and separated from the first conductive part by a gap.
At least a portion of the first part and a portion of the second part are separated by the gap. In some embodiments, another part of the first part and another part of the second part may meet to form a ‘closed’ loop. Alternatively, in some embodiments, the first part and the second part do not meet and they form an ‘open’ loop. The open loop may be asymmetric. It may support a closed loop electric current where a displacement current bridges the gap. It may support an additional resonance that overlaps an existing resonance associated with the conductive ground element to provide an increased bandwidth and/or better efficiency.
According to various embodiments of the invention there is provided an antenna arrangement comprising: an antenna element associated with a conductive ground element; and opposite the antenna element, a first conductive part extending away from the conductive ground element and a second conductive part extending away from the conductive ground element parallel to the first conductive ground element and separated therefrom by a gap.
According to various embodiments of the invention there is provided a method of manufacturing a multi band antenna arrangement comprising: obtaining a conductive ground element having a first end and an opposing second end and comprising an extension element, at the second end, separated from the conductive ground element by a gap; and locating a directly fed antenna element at the first end of a conductive ground element.
According to various embodiments of the invention there is provided a printed wiring board component comprising: a conductive ground element having a first end for association with an antenna element and a second end; a first conductive part extending from the second end of the conductive ground element; and a second conductive part extending from the second end of the conductive ground element and separated from the first conductive part by a gap.
In various embodiments of the invention, a desired multi band performance can be achieved using the configuration of the first part, the second part and the gap.
In various embodiments of the invention, a desired performance can be achieved while respecting an imposed constraint such as a maximum or minimum size for the conductive ground element.
According to various embodiments of the invention there is provided an antenna arrangement comprising: a conductive ground element; a first antenna element operable at least at a first frequency; a second antenna element operable at least at the first frequency; a first conductive part extending the conductive ground element; and a second conductive part extending the conductive ground element and separated from the first conductive part by a gap, wherein the first conductive part, the second conductive part and the gap are configured to provide isolation between the first antenna element and the second antenna element at least at the first frequency.
According to various embodiments of the invention there is provided a printed wiring board component comprising: a conductive ground element having a first portion for association with; a first antenna element operable at least at a first frequency and a second portion for association with a second antenna element operable at least at the first frequency; and a first conductive part extending the conductive ground element and a second conductive part extending the conductive ground element and separated from the first conductive part by a gap, wherein the first conductive part, the second conductive part and the gap are configured to provide isolation between the first antenna element and the second antenna element at least at the first frequency.
According to various embodiments of the invention there is provided a method comprising the assembly of an antenna arrangement comprising: a conductive ground element; a first antenna element operable at least at a first frequency; a second antenna element operable at least at the first frequency;
a first conductive part extending the conductive ground element; and
a second conductive part extending the conductive ground element and separated from the first conductive part by a gap, wherein the first conductive part, the second conductive part and the gap are configured to provide isolation between the first antenna element and the second antenna element at least at the first frequency.
In various embodiments of the invention there is provided a method comprising the assembly of the antenna arrangement. which may include the configuration of the dimensions, positions, shape and/or relative mutual proximity of the first and second conductive parts.
For a better understanding of various embodiments of the present invention reference will now be made by way of example only to the accompanying drawings in which:
an antenna element 2 associated with a conductive ground element 3;
a first conductive part 16 extending away from the conductive ground element 3 and a second conductive part 18 extending away from the conductive ground element 3 and separated from the first conductive part 16 by a gap 8.
The conductive ground element 3 has a first end 12 and a second end 14 opposite the first end. The antenna element 2 is positioned at or near the first end 12.
The antenna element 2 is an electrically conductive monopole element that is directly fed via feed 4 at one of its ends. The other end is free-standing. There is typically a matching network connected to the feed on the ground element 3. In the embodiment illustrated, the antenna element 2 is a planer inverted L antenna (PILA) positioned adjacent the edge of the first end 12 of the conductive ground element 3. The PILA has as it lowest resonant mode a λ/4 mode .i.e. at resonance the electrical length of the antenna element equals λ/4, where λ is the wavelength at resonance. Although a particular type of antenna element 2 has been illustrated, it should be appreciated that other types of antenna elements may be used such as e.g. a planar inverted F antenna (PIFA), a patch antenna, a wire antenna (monopole, dipole, helix, etc), and other known antenna elements as used in the art.
The conductive ground element 3 provides a ground potential reference. It operates as a ground plane for the antenna element 2.
The conductive ground element 3 comprises a significant surface area of continuous solid conductor between the first end 12 and the second end 14.
This area may, for example, be used as a printed wiring board (PWB) for carrying electronic components and may be of substantially rectangular shape. The conductive ground element 3 may be on one of more layers of the printed wiring board (PWB), in a multi-layer printed wiring board.
The conductive ground element 3 may be formed from metallic or conductive objects present in a typical portable electronic device, e.g. battery, shields, internal or external covers, frames, and other electronic or mechanical parts, whilst not being limited to this list of parts. These parts may or may not be electrically connected to the printed wiring board.
The first conductive part 16 and the second conductive part 18 are both situated at an extremity 6 of the conductive ground element 3 that includes the second end 14 of the conductive ground element 3 and is opposite the first end 12 of the conductive ground element 3. The first conductive part 16 and the second conductive part 18 may be elements that are integral portions of the conductive ground element 3 or may be additional elements that are galvanically connected to the conductive ground element 3.
The antenna arrangement 10 may be single band or multi-band.
The electrical length of the conductive ground element 3 may, in some embodiments, be used to tune the high band resonance 32 which is dependent upon resonant modes excited in the conductive ground element 3 by the antenna element 2 and also tune the low band resonance 36A which is typically a harmonic of the high band resonant frequency. For example, in the example illustrated in
The configuration and electrical lengths of the first part 16 and second part 18 may, in some embodiments, be used to tune the low band resonance 34.
The conductive parts 16, 18 operate as extensions to the conductive ground element 3. The FIGS. 1 and 2A-2E illustrate various different configurations for the first and second conductive parts 16 and 18 and the intervening gap 8.
It has been observed that extending the electrical length of the conductive element 3 using the first conductive part 16 and the second conductive part 18 increases the low band resonance bandwidth 34.
It has been observed that the increase in bandwidth can be greater for those arrangements that are asymmetric (
It has been observed that some configurations of the first and second parts (e.g.
The arrangement of the first conductive part 16, the second conductive part 18 and the gap 8 may be chosen so that the additional resonance created by the closed electric current loop has a resonant frequency 36B adjacent the existing resonant frequency 36A of the antenna arrangement 10 thereby increasing the bandwidth. Although, the first conductive part 16 and the second conductive part 18 have been described as modifying the low frequency band, it should be appreciated that by varying the parts and, in particular their electrical lengths, they could alternatively be used to modify the high frequency band 32.
The performance properties of the low band resonance 34 may also be tuned by adjusting the size and shape of the gap 8 defined between the conductive ground element 3, the first part 16 and the second part 18. Reducing the size of the gap encourages a displacement current between the first and second parts which forms a closed electric current loop and an associated additional resonant mode 36B.
In comparison, the gaps 8 illustrated in
In the example illustrated in
If a large area gap 8 is used, as illustrated in
The first conductive part 16 and the second conductive part 18 form an antenna-like structure. It may, in some embodiments, be possible to use a complimentary form of antenna structure which replaces gap with conductor and conductor with gap. This will reverse the Electric and Magnetic fields and may enable polarization diversity.
The conductive ground element 3 has a first end 12 and a second end 14 opposite the first end. In the illustrated example, the first antenna element 2 is positioned at or near the first end 12 and the second antenna element 2′ is positioned at or near the second end 14 close to the second conductive part.
In this example, the first antenna element 2 is an electrically conductive monopole element that is directly fed via feed 4 at one of its ends. The other end is free-standing. There is typically a matching network connected to the feed on the ground element 3. The first antenna element 2 may be a planar inverted F antenna (PIFA) as illustrated in
In this example, the second antenna element 2′ is also an electrically conductive monopole element that is directly fed via feed 4′ at one of its ends. The other end is free-standing. There is typically a matching network connected to the feed on the ground element 3. The antenna element 2′ may be a planar inverted F antenna (PIFA) as illustrated in
The conductive ground element 3 provides a ground potential reference. It operates as a ground plane for the first antenna element 2 and the second antenna element 2′.
The conductive ground element 3 may comprise a significant surface area of continuous solid conductor between the first end 12 and the second end 14.
This area may, for example, be used as a printed wiring board (PWB) for carrying electronic components and may be of substantially rectangular shape. The conductive ground element 3 may be on one or more layers of the printed wiring board (PWB), in a multi-layer printed wiring board.
The conductive ground element 3 may be formed from metallic or conductive objects present in a typical portable electronic device, e.g. battery, shields, internal or external covers, frames, and other electronic or mechanical parts, whilst not being limited to this list of parts. These parts may or may not be electrically connected to the printed wiring board.
The first conductive part 16 and the second conductive part 18 are both situated, in this example, at an extremity 6 of the conductive ground element 3 that includes the second end 14 of the conductive ground element 3 and is opposite the first end 12 of the conductive ground element 3. The first conductive part 16 and the second conductive part 18 may be elements that are integral portions of the conductive ground element 3 or may be additional elements that are galvanically connected to the conductive ground element 3.
The electrical length of the conductive ground element 3 may, in some embodiments, be used to tune the low band resonances 34, 34′. In the example illustrated in
The configuration and electrical lengths of the first part 16 and second part 18 may, in some embodiments, be used to tune the isolation between the first antenna element 2 and the second antenna element 2′. The isolation (S21) is illustrated in
The conductive parts 16, 18 operate as extensions to the conductive ground element 3 (ground element extensions)
Modes occurring in the conductive ground element 3 naturally, are enhanced by placing the extending conductive parts 16, 18 where most of the current tends to flow in the conductive ground element 3 (along the edge) and then bringing the extending conductive parts 16, 18 into proximity.
As an example, the conductive part 16 may, in combination with the conductive ground element 3, form a first resonant mode, and the conductive part 18 may in combination with the conductive ground element 3, form a second resonant mode. The proximal placement of both conductive parts 16 and 18 couples the two distinct modes. The FIGS. 8 and 2A-2E illustrate various different configurations for the first and second conductive parts 16 and 18 and the intervening gap 8.
Without the gap 8 and therefore without the conductive parts 16 and 18, both the first antenna 2 and the second antenna 2′ share the same chassis mode or conductive ground element resonance, resulting in a high level of antenna coupling between the first antenna 2 and the second antenna 2′.
With the introduction of the gap 8 formed by adding the conductive parts 16 and 18, two discrete chassis modes are created, each chassis mode having it's own resonant frequency. The first antenna 2 is tuned to the first chassis mode, and the second antenna 2′ is tuned to the second chassis mode. Since the two chassis modes have different current distributions, the isolation between the first antenna 2 and second antenna 2′ are improved.
It has been observed for some configurations of the first and second parts (e.g.
It may be desirable to keep the gap 8 sufficiently wide to prevent too strong coupling between the first conductive part 16 and the second conductive part 18 which would reduce the isolation between the antenna 2 and the second antenna 2′. A sufficiently wide gap may be greater than 1/10th the size of the resonant wavelength.
In the example of
In the example of
The antenna 2 and the second antenna 2′ may be, for example, a main antenna and diversity antenna operating in the same or overlapping frequency ranges. The antenna 2 and the second antenna 2′ may be, for example, multiple input and/or multiple output antennas (e.g. MIMO) operating in the same or overlapping frequency ranges.
The antenna 2 and the second antenna 2′ share the dominant radiator the extended conductive ground element 3. The first part 16 and second part 18 extend and adapt the conductive ground element 3. They create additional resonances or ‘chassis modes’ which improve the isolation between the antenna 2 and the second antenna 2′.
The apparatus 10 may be any type of apparatus that transmits and/or receives radio waves.
It may, for example, operate in any one or more of the following frequency bands: AM radio (0.535-1.705 MHz); FM radio (76-108 MHz); Bluetooth (2400-2483.5 MHz); WLAN (2400-2483.5 MHz); HLAN (5150-5850 MHz); GPS (1570.42-1580.42 MHz); US-GSM 850 (824-894 MHz); EGSM 900 (880-960 MHz); EU-WCDMA 900 (880-960 MHz); PCN/DCS 1800 (1710-1880 MHz); US-WCDMA 1900 (1850-1990 MHz); WCDMA 2100 (Tx: 1920-1980 MHz Rx: 2110-2180 MHz); PCS1900 (1850-1990 MHz); UWB Lower (3100-4900 MHz); UWB Upper (6000-10600 MHz); DVB-H (470-702 MHz); DVB-H US (1670-1675 MHz); DRM (0.15-30 MHz); Wi Max (2300-2400 MHz, 2305-2360 MHz, 2496-2690 MHz, 3300-3400 MHz, 3400-3800 MHz, 5250-5875 MHz); DAB (174.928-239.2 MHz, 1452.96-1490.62 MHz); RFID LF (0.125-0.134 MHz); RFID HF (13.56-13.56 MHz); RFID UHF (433 MHz, 865-956 MHz, 2450 MHz).
The antenna arrangement 10 may, for example, be manufactured by obtaining a conductive ground element having a first end and an opposing second end and comprising an extension element, at the second end, separated from the conductive ground element by a gap; and locating a directly fed antenna element at the first end of a conductive ground element. The required conductive ground element may be provided as a printed wiring board component.
Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.
Features described in the preceding description may be used in combinations other than the combinations explicitly described.
Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.
Number | Date | Country | Kind |
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PCT/IB2007/003652 | Sep 2007 | IB | international |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/62582 | 9/19/2008 | WO | 00 | 5/4/2010 |