WO1997033340A1 - A device for reducing the output of an antenna - Google Patents
A device for reducing the output of an antenna Download PDFInfo
- Publication number
- WO1997033340A1 WO1997033340A1 PCT/SE1997/000256 SE9700256W WO9733340A1 WO 1997033340 A1 WO1997033340 A1 WO 1997033340A1 SE 9700256 W SE9700256 W SE 9700256W WO 9733340 A1 WO9733340 A1 WO 9733340A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- antenna
- supply point
- reducing
- output
- ferromagnetic
- Prior art date
Links
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 7
- 239000004020 conductor Substances 0.000 claims abstract description 6
- 230000005294 ferromagnetic effect Effects 0.000 claims abstract description 5
- 239000007779 soft material Substances 0.000 claims abstract description 5
- 239000003302 ferromagnetic material Substances 0.000 claims description 4
- 239000003638 chemical reducing agent Substances 0.000 claims description 3
- 230000005540 biological transmission Effects 0.000 description 7
- 238000013016 damping Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 208000027418 Wounds and injury Diseases 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 208000014674 injury Diseases 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 206010065929 Cardiovascular insufficiency Diseases 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000013080 microcrystalline material Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/3827—Portable transceivers
- H04B1/3833—Hand-held transceivers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
- H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
- H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
- H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
- H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
- H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
- H01Q1/245—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
Definitions
- the present invention relates to a device for reducing the energy radiated from an antenna in a radio communications apparatus, the antenna being connected to a transmitter via a supply point.
- the antenna in daily parlance mobile telephones, the antenna is placed in such a manner that it is located closely adjacent the user's head. During those periods when the apparatus is transmitting, a part of the radiated energy will be absorbed in the head tissue of the user. The amount of energy that can be absorbed in the head tissue of the user without injury or risk of injury is a matter for debate. A measurement of the absorbed energy discloses the so-called “sar” value (specific absorption rate). An upper limit for this "sar" value is to be established.
- the present invention has for its object to design the device intimated by way of introduction such that the above-considered problems are obviated.
- the present invention has for its object to realise a device which permits an accurately adapted reduction of the radiated energy from a transmitter antenna without sensitivity on reception being negatively affected to any appreciable degree.
- the present invention also has for its object to realise a device which is simple and economical in manufacture and which has a long service life.
- the device according to the invention is characterized in that there is disposed, in the region of the supply point of the antenna, a body of ferromagnetic, soft material.
- the ferromagnetic material is a ferrite.
- Fig. 1 is a cross section through a lower portion of a rod antenna
- Fig. 2 is a cross section through a helix antenna. DESCRIPTION OF PREFERRED EMBODIMENTS
- reference numeral 1 relates to an outer casing, or housing, of electrically insulating, non-magnetic material.
- a radiator 2 which, in this embodiment, is designed as a rod.
- the radiator 2 merges in a signal conductor 3 which extends through a sleeve 4 of insulating material in the connection terminal 5 of the antenna.
- the antenna has a supply point 6 which may be defined as that point along the conductor consisting of the components 2 and 3 where the upper portion of the conductor begins to function as a radiator. In the Drawings, the supply point 6 is located just above the upper end of the insulating sleeve 4.
- a body 7 of ferromagnetic, soft material In the region of the supply point 6 of the antenna, there is disposed a body 7 of ferromagnetic, soft material.
- this body is tubular or cylindrical and is disposed coaxially about the metallic conductor 2, 3 of the antenna.
- the body 7 will deflect or drain energy from the antenna, this energy being converted to heat in the body.
- the body 7 is thermally connected to a heat reducer, i.e. a body which has the capacity to absorb and lead off heat.
- this heat reducer is realised in that the body 7 is cast in a non-electrically conductive plastic material which may be disposed to fill out the space interiorly in the outer casing 1 of the antenna.
- ferrites have proved to be particular suitable.
- the term ferrite in this context is taken to signify a sintered ceramic, micro crystalline material with a spatially centred cubic crystal lattice.
- the material consists of iron oxide (Fe2Q3) and a metal mixture.
- the most common combinations in the metal mixture are manganese / zinc and nickel /zinc.
- a ferrite quality which is available from Philips carrying material designation 4S2 has proved to be especially usable within the pertinent frequency range of from 400 MHz to 2 GHz.
- the damping of the energy radiated from the radiator 2 which is realised by the body 7 is approximately proportional to the axial length of the body 7.
- the damping which is achieved of the radiated energy is non-linear in relation to the output supplied to the antenna.
- the damping is very low in low outputs, in order subsequently to increase and once again fade at high outputs.
- the body 7 may be adapted in such a manner that it only gives insignificant damping of the antenna performance on reception, since the output handled by the antenna is then very modest, while the intended damping is achieved on transmission, when the output handled by the antenna is considerably greater.
- This phenomenon entails major advantages in systems operating in simplex, i.e. when transmission and reception take place separately in time.
- the advantages are also great in such systems (e.g. GSM) in which transmission takes place intermittently, while probably no - or only insignificant - advantages will be attained in systems which operate in full duplex, i.e. when transmission and reception take place simultaneously.
- Fig. 2 The embodiment illustrated in Fig. 2 is wholly analogous with the embodiment according to Fig. 1 apart from the fact that the radiator 2 is designed as a helix, which gives a considerably shorter construction length of the antenna.
- An antenna of this type is extra critical as regards the "sar" value, since it is physically short and is therefore located very close to the user's head.
- Fig. 2 the same reference numerals have otherwise been employed as in Fig. 1. A detailed description of the embodiment according to Fig. 2 would therefore be a repetition of the foregoing disclosures.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Support Of Aerials (AREA)
- Details Of Aerials (AREA)
- Suspension Of Electric Lines Or Cables (AREA)
- Transmitters (AREA)
Abstract
In a device for reducing the energy radiated from an antenna in a radio communications apparatus, the antenna is connected to a transmitter via a supply point (6). In the region of the supply point (6) of the antenna, there is disposed a body of ferromagnetic, soft material, for example ferrite. The body (7) is tubular and surrounds the signal conductor of the antenna.
Description
A DEVICE FOR REDUCING THE OUTPUT OF AN ANTENNA
TECHNICAL FIELD
The present invention relates to a device for reducing the energy radiated from an antenna in a radio communications apparatus, the antenna being connected to a transmitter via a supply point.
BACKGROUND ART
In many types of radio communications apparatus, in daily parlance mobile telephones, the antenna is placed in such a manner that it is located closely adjacent the user's head. During those periods when the apparatus is transmitting, a part of the radiated energy will be absorbed in the head tissue of the user. The amount of energy that can be absorbed in the head tissue of the user without injury or risk of injury is a matter for debate. A measurement of the absorbed energy discloses the so-called "sar" value (specific absorption rate). An upper limit for this "sar" value is to be established.
Given that developments have so far pointed in the direction of striving for as high an output effect and long operating time as possible from the transmitter in relation to the battery power employed, many mobile telephones today have transmission outputs which may be feared can give "sar" values which are excessively high. There is thus a need in the art to be able to adapt the output of the transmitter in such a manner that the "sar" value thus obtained falls immediately beneath the maximum permitted level.
If possible, the above-mentioned reduction of radiated energy during transmission time should not need to be bought at the expense of a corresponding reduction of the degree of efficiency in reception, since the energy absorbed by the antenna is at a considerably lower level on reception than on transmission.
PROBLEM STRUCTURE
The present invention has for its object to design the device intimated by way of introduction such that the above-considered problems are obviated. In particular, the present invention has for its object to realise a device which permits an accurately adapted reduction of the radiated energy from a transmitter antenna without sensitivity on reception being negatively affected to any appreciable degree. The present invention also has for its object to realise a device which is simple and economical in manufacture and which has a long service life.
SOLUTION
The objects forming the basis of the present invention will be attained if the device according to the invention is characterized in that there is disposed, in the region of the supply point of the antenna, a body of ferromagnetic, soft material.
Suitably, the ferromagnetic material is a ferrite.
Further advantages will be attained if the device according to the present invention is also given one or more of the characterizing features as set forth in appended Claims 3 and 4.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings:
Fig. 1 is a cross section through a lower portion of a rod antenna; and
Fig. 2 is a cross section through a helix antenna.
DESCRIPTION OF PREFERRED EMBODIMENTS
In Fig. 1, reference numeral 1 relates to an outer casing, or housing, of electrically insulating, non-magnetic material. Within the outer casing, there is a radiator 2 which, in this embodiment, is designed as a rod. The radiator 2 merges in a signal conductor 3 which extends through a sleeve 4 of insulating material in the connection terminal 5 of the antenna.
The antenna has a supply point 6 which may be defined as that point along the conductor consisting of the components 2 and 3 where the upper portion of the conductor begins to function as a radiator. In the Drawings, the supply point 6 is located just above the upper end of the insulating sleeve 4.
In the region of the supply point 6 of the antenna, there is disposed a body 7 of ferromagnetic, soft material. Preferably, this body is tubular or cylindrical and is disposed coaxially about the metallic conductor 2, 3 of the antenna.
Depending upon the material properties in the body 7 and its dimensions, in particular its axial extent, the body will deflect or drain energy from the antenna, this energy being converted to heat in the body. For this reason, the body 7 is thermally connected to a heat reducer, i.e. a body which has the capacity to absorb and lead off heat. In one practical embodiment, this heat reducer is realised in that the body 7 is cast in a non-electrically conductive plastic material which may be disposed to fill out the space interiorly in the outer casing 1 of the antenna.
Among the ferromagnetic, soft materials that are conceivable for producing the body 7, ferrites have proved to be particular suitable. The term ferrite in this context is taken to signify a sintered ceramic, micro crystalline material with a spatially centred cubic crystal lattice. The material consists of iron oxide (Fe2Q3) and a metal mixture. The most common combinations in the metal mixture are manganese / zinc and nickel /zinc. In particular, a ferrite quality which is available from Philips carrying material designation 4S2 has proved to be especially usable within the pertinent frequency range of from 400 MHz to 2 GHz.
The damping of the energy radiated from the radiator 2 which is realised by the body 7 is approximately proportional to the axial length of the body 7.
One of the material properties of the ferrite employed implies that the damping which is achieved of the radiated energy is non-linear in relation to the output supplied to the antenna. Thus, the damping is very low in low outputs, in order subsequently to increase and once again fade at high outputs. As a result, the body 7 may be adapted in such a manner that it only gives insignificant damping of the antenna performance on reception, since the output handled by the antenna is then very modest, while the intended damping is achieved on transmission, when the output handled by the antenna is considerably greater. This phenomenon entails major advantages in systems operating in simplex, i.e. when transmission and reception take place separately in time. The advantages are also great in such systems (e.g. GSM) in which transmission takes place intermittently, while probably no - or only insignificant - advantages will be attained in systems which operate in full duplex, i.e. when transmission and reception take place simultaneously.
The embodiment illustrated in Fig. 2 is wholly analogous with the embodiment according to Fig. 1 apart from the fact that the radiator 2 is designed as a helix, which gives a considerably shorter construction length of the antenna. An antenna of this type is extra critical as regards the "sar" value, since it is physically short and is therefore located very close to the user's head. In Fig. 2, the same reference numerals have otherwise been employed as in Fig. 1. A detailed description of the embodiment according to Fig. 2 would therefore be a repetition of the foregoing disclosures.
The present invention may be modified without departing from the spirit and scope of the appended Claims.
Claims
1. A device for reducing the energy radiated from an antenna in a radio communications apparatus, the antenna being connected to a transmitter via a supply point (6), characterized in that there is disposed, in the region of the supply point (6) of the antenna, a body (7) of ferromagnetic, soft material.
2. The device as claimed in Claim 1, characterized in that the ferromagnetic material is a ferrite.
3. The device as claimed in Claim 1 or 2, characterized in that the body (7) of ferromagnetic material is tubular and surrounds the signal conductor of the antenna in immediate conjunction with the supply point (6).
4. The device as claimed in any of Claims 1 to 3, characterized in that the body (7) of ferromagnetic material is thermally connected to a heat reducer.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9600824-8 | 1996-03-04 | ||
| SE9600824A SE9600824L (en) | 1996-03-04 | 1996-03-04 | Power reduction device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1997033340A1 true WO1997033340A1 (en) | 1997-09-12 |
Family
ID=20401646
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/SE1997/000256 WO1997033340A1 (en) | 1996-03-04 | 1997-02-17 | A device for reducing the output of an antenna |
Country Status (2)
| Country | Link |
|---|---|
| SE (1) | SE9600824L (en) |
| WO (1) | WO1997033340A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999063621A1 (en) * | 1998-05-29 | 1999-12-09 | Telefonaktiebolaget Lm Ericsson (Publ) | High efficiency, multi-band antenna for a radio communication device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0603081A1 (en) * | 1992-12-17 | 1994-06-22 | Alcatel N.V. | Portable radio telephone with means for protecting its user from electromagnetic radiation |
| WO1994014208A1 (en) * | 1992-12-16 | 1994-06-23 | University Of Bradford | Improvements in or relating to portable phones |
| WO1994019841A1 (en) * | 1993-02-18 | 1994-09-01 | Wave Technologies Inc. | Radiation shield |
| WO1996005682A2 (en) * | 1994-08-01 | 1996-02-22 | Luxon Norval N | Radiation shielding and range extending antenna assembly |
-
1996
- 1996-03-04 SE SE9600824A patent/SE9600824L/en not_active Application Discontinuation
-
1997
- 1997-02-17 WO PCT/SE1997/000256 patent/WO1997033340A1/en active Application Filing
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1994014208A1 (en) * | 1992-12-16 | 1994-06-23 | University Of Bradford | Improvements in or relating to portable phones |
| EP0603081A1 (en) * | 1992-12-17 | 1994-06-22 | Alcatel N.V. | Portable radio telephone with means for protecting its user from electromagnetic radiation |
| WO1994019841A1 (en) * | 1993-02-18 | 1994-09-01 | Wave Technologies Inc. | Radiation shield |
| WO1996005682A2 (en) * | 1994-08-01 | 1996-02-22 | Luxon Norval N | Radiation shielding and range extending antenna assembly |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999063621A1 (en) * | 1998-05-29 | 1999-12-09 | Telefonaktiebolaget Lm Ericsson (Publ) | High efficiency, multi-band antenna for a radio communication device |
Also Published As
| Publication number | Publication date |
|---|---|
| SE9600824D0 (en) | 1996-03-04 |
| SE9600824L (en) | 1997-09-05 |
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