EP0892456A1 - Non-contact coupling through a dielectric - Google Patents
Non-contact coupling through a dielectric Download PDFInfo
- Publication number
- EP0892456A1 EP0892456A1 EP98305745A EP98305745A EP0892456A1 EP 0892456 A1 EP0892456 A1 EP 0892456A1 EP 98305745 A EP98305745 A EP 98305745A EP 98305745 A EP98305745 A EP 98305745A EP 0892456 A1 EP0892456 A1 EP 0892456A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- dielectric
- spirals
- conductive
- contact connection
- coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- 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
-
- 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
- H01Q1/1271—Supports; Mounting means for mounting on windscreens
- H01Q1/1285—Supports; Mounting means for mounting on windscreens with capacitive feeding through the windscreen
Definitions
- the present invention relates to a system for transmitting radio frequency energy through a dielectric, for example through a plastics wall of an equipment containing box, and to an antenna assembly including the system for transmitting radio frequency energy through the dielectric.
- RF electrical equipment is often contained in a hermetically sealed equipment box.
- a dedicated connector which passes through the dielectric wall of the equipment box. This is undesirable, firstly as the dedicated connector can be expensive to provide, therefore giving an unacceptable additional cost to the equipment, and secondly as the connector constitutes a weak point in the hermetic seal around the equipment.
- US-A-4,238,799 discloses a non-contact connection using capacitive coupling to allow transmission of signals to and from an in-car mobile telephone antenna.
- the capacitive coupler is combined with an inductive susceptance to create a well matched system and thereby ensures a low level of reflected energy.
- the coupling of the connection is optimised by selection of an appropriate inductor.
- US-A-5,105,201 discloses a glass mounted antenna for a car radio having a conductive spiral coil connected to the antenna for coupling with a second conductive spiral coil on the inside of the glass which is connected to a receiver.
- a non-contact connection through a dielectric comprising a pair of counter-wound conductive spirals provided on opposite sides of the dielectric, is characterised in that a pair of ground planes sandwich the conductive spirals and the dielectric.
- the counter-wound conductive spirals are inductively coupled to each other to allow transmission of signals through the dielectric.
- the ground planes create a capacitative coupling effect and constrain the fields in the device, resulting in a low profile device with reduced stray radiation and therefore high efficiency.
- the ground planes also allow greater control over the environment in which the device operates, allowing greater control of the impedances within the device so that the bandwidth may be optimised.
- a capacitor is provided at the input of each of the spirals. This gives a low reflection coefficient which ensures low transmission losses.
- the connection can be matched by adjusting the capacitance of the capacitor. It is possible to provide a variable capacitance to allow the coupling to be optimised for any given dielectric substrate through which the signals are to be transmitted, and depending on the frequency of the signals to be transmitted. However, due to the large bandwidth for which the system is preferably designed, the system is relatively insensitive to the dielectric properties of the dielectric, and accordingly a standard capacitance is acceptable.
- the two counter-wound conductive spirals have the same configuration.
- the conductive spirals advantageously have either a rectangular, square or circular configuration.
- the counter-wound conductive spirals may be formed from wire, however it is preferred that the spirals are formed onto a substrate, for example by a conventional deposition or etching method. Preferably the groound planes are formed on the rear of the substrate. Where a capacitor is provided to optimise the connection, the capacitor is advantageously printed or otherwise formed on the substrate with the conductive spiral. This is beneficial as it allows the conductive spiral and capacitive element to be encapsulated to help prevent ingress of water or other fluid which may damage the device, and results in a more compact structure.
- the two counter-wound conductive spirals are rotatably provided with respect to each other. This allows the coupling to be formed as a rotatable coupling through which signals can be transmitted.
- the radio frequency energy to be transmitted by the coupling according to the present invention preferable has a frequency of at least 50MHz, and preferably has a maximum frequency of 2,000MHz.
- an antenna assembly comprises a non-contact connection according to the first aspect of the present invention, and an antenna connected to one of the conductive spirals of the non-contact junction.
- the antenna assembly includes a matching network to match the antenna and the non-contact coupling.
- the coupling includes two counter-wound spirals (1,2) formed of a conductive material. These spirals (1,2) are printed onto respective dielectric substrates (3,4) on the opposite sides of which are conductive ground planes (8,9).
- the spirals (1,2) may alternatively be formed on the dielectric substrates (3,4) by etching, or may be formed separately and provided on the dielectric substrates (3,4) subsequently.
- a capacitor (10) is connected in series with each of the conductive spirals (1,2).
- the capacitors are printed on the dielectric substrates (3,4) together with the conductive spirals (1,2), and are formed, for example by trimming, to optimise the transmission characteristics of the coupling for the particular dielectric through which the coupling is to be made and for the particular frequency range of the signals to be transmitted through the dielectric.
- Each spiral (1,2), dielectric substrate (3,4) and ground plane (8,9) is provided against the opposite faces of a dielectric layer (5), forming a multi-layer sandwich with the dielectric layer (5) in the centre and the ground planes (8,9) on the outer edges.
- an RF signal to be transmitted through the dielectric layer (5) is supplied through a capacitor to one of the conductive spirals (1,2). Due to the inductive coupling through the dielectric layer (5), RF signals are induced in the other conductive spiral (1,2) from where the signals are output through the second capacitor.
- the dielectric substrate (5) may be the plastics wall of an equipment box.
- electrical equipment is provided within the box, and is connected to one of the conductive spirals (1,2) which is provided on the inner wall of the box.
- the other conductive spiral (1,2) is provided on the outer surface of the box, and forms the non-contact inductive coupling between the inside and outside of the box through which signals are transmitted to and from the equipment within the box.
- FIG. 2 A specific example of a coupling according to the present invention is shown in Figure 2. This is designed to work at a frequency of 184MHz through a lmm dielectric wall of polycarbonate.
- the dielectric substrates (3,4) on which the conductive spirals (1,2) are formed are also polycarbonate substrates having a thickness of 2.4mm, and being approximately 40mm square.
- the ground plane (8,9) is formed on the rear of the dielectric substrate (3,4), and a 10pf capacitor (10) is provided on the same side of the substrate (3,4) as the ground plane (8,9). Both the conductive spirals (1,2) and both the ground planes (8,9) are formed from copper.
- the capacitor (10) is connected to the outer end of the spiral (1,2) and the inner end of the spiral (1,2) is connected to the ground plane (8,9) via plated through holes (11) extending through the substrate (3,4). This allows the surface on which the spiral (1,2) is formed to remain flat.
- the coupling may be used in conjunction with an antenna (6,7).
- the antenna (6,7) is connected directly to one of the conductive spirals (1,2).
- An RF signal is applied to the other conductive spiral (1,2) via an input (12) from within a housing (13), and this is coupled through the non-contact inductive coupling to the other conductive spiral (1,2) and to the antenna (6,7) to transmit the signal.
- This system can also be used for reception of the signals by the antenna (6,7).
- Figure 3 shows a loop antenna (6) used in conjunction with the non-contact coupling
- Figure 4 shows a monopole antenna (7) having a helical design, although other antennas may be used.
- the non-contact coupling can be formed as a rotatable coupling.
- the dielectric is an air gap.
- one of the ground plates (3) and the associated conductive spiral (1) are rotatably mounted with respect to the other ground plate (4) and spiral (2). Due to the spiral design of the conductive coupling, the relative angular position of the substrates (3,4) and conductors (1,2) will not affect the coupling.
Abstract
The present invention relates to a system for
transmitting radio frequency energy through a dielectric
(5), for example through a plastics wall of an equipment
containing box, and to an antenna assembly including the
system for transmitting radio frequency energy through the
dielectric.
A non-contact connection through a dielectric (5)
comprising a pair of counter-wound conductive spirals (1,2)
provided on opposite sides of the dielectric (5), is
characterised in that a pair of ground planes (8,9)
sandwich the conductive spirals (1,2) and the dielectric
(5).
Description
The present invention relates to a system for
transmitting radio frequency energy through a dielectric,
for example through a plastics wall of an equipment
containing box, and to an antenna assembly including the
system for transmitting radio frequency energy through the
dielectric.
RF electrical equipment is often contained in a
hermetically sealed equipment box. To pass RF signals to
and from the equipment, it is known to provide a dedicated
connector which passes through the dielectric wall of the
equipment box. This is undesirable, firstly as the
dedicated connector can be expensive to provide, therefore
giving an unacceptable additional cost to the equipment,
and secondly as the connector constitutes a weak point in
the hermetic seal around the equipment.
US-A-4,238,799 discloses a non-contact connection
using capacitive coupling to allow transmission of signals
to and from an in-car mobile telephone antenna. In this
case, the capacitive coupler is combined with an inductive
susceptance to create a well matched system and thereby
ensures a low level of reflected energy. The coupling of
the connection is optimised by selection of an appropriate
inductor.
US-A-5,105,201 discloses a glass mounted antenna for
a car radio having a conductive spiral coil connected to
the antenna for coupling with a second conductive spiral
coil on the inside of the glass which is connected to a
receiver.
According to a first aspect of the present invention,
a non-contact connection through a dielectric comprising a
pair of counter-wound conductive spirals provided on
opposite sides of the dielectric, is characterised in that
a pair of ground planes sandwich the conductive spirals and
the dielectric.
With this arrangement, the counter-wound conductive
spirals are inductively coupled to each other to allow
transmission of signals through the dielectric. The ground
planes create a capacitative coupling effect and constrain
the fields in the device, resulting in a low profile device
with reduced stray radiation and therefore high efficiency.
The ground planes also allow greater control over the
environment in which the device operates, allowing greater
control of the impedances within the device so that the
bandwidth may be optimised.
It is preferred that a capacitor is provided at the
input of each of the spirals. This gives a low reflection
coefficient which ensures low transmission losses. In this
case, the connection can be matched by adjusting the
capacitance of the capacitor. It is possible to provide a
variable capacitance to allow the coupling to be optimised
for any given dielectric substrate through which the
signals are to be transmitted, and depending on the
frequency of the signals to be transmitted. However, due
to the large bandwidth for which the system is preferably
designed, the system is relatively insensitive to the
dielectric properties of the dielectric, and accordingly a
standard capacitance is acceptable.
Advantageously, the two counter-wound conductive
spirals have the same configuration. The conductive
spirals advantageously have either a rectangular, square or
circular configuration.
The counter-wound conductive spirals may be formed
from wire, however it is preferred that the spirals are
formed onto a substrate, for example by a conventional
deposition or etching method. Preferably the groound
planes are formed on the rear of the substrate. Where a
capacitor is provided to optimise the connection, the
capacitor is advantageously printed or otherwise formed on
the substrate with the conductive spiral. This is
beneficial as it allows the conductive spiral and
capacitive element to be encapsulated to help prevent
ingress of water or other fluid which may damage the
device, and results in a more compact structure.
It is preferred that the two counter-wound conductive
spirals are rotatably provided with respect to each other.
This allows the coupling to be formed as a rotatable
coupling through which signals can be transmitted.
The radio frequency energy to be transmitted by the
coupling according to the present invention preferable has
a frequency of at least 50MHz, and preferably has a maximum
frequency of 2,000MHz.
According to a second aspect of the present invention,
an antenna assembly comprises a non-contact connection
according to the first aspect of the present invention, and
an antenna connected to one of the conductive spirals of
the non-contact junction.
It is preferred that the antenna assembly includes a
matching network to match the antenna and the non-contact
coupling.
The present invention will now be described in
accordance with the accompanying drawings, in which:
As shown in Figure 1, the coupling includes two
counter-wound spirals (1,2) formed of a conductive
material. These spirals (1,2) are printed onto respective
dielectric substrates (3,4) on the opposite sides of which
are conductive ground planes (8,9). The spirals (1,2) may
alternatively be formed on the dielectric substrates (3,4)
by etching, or may be formed separately and provided on the
dielectric substrates (3,4) subsequently. A capacitor (10)
is connected in series with each of the conductive spirals
(1,2). The capacitors are printed on the dielectric
substrates (3,4) together with the conductive spirals
(1,2), and are formed, for example by trimming, to optimise
the transmission characteristics of the coupling for the
particular dielectric through which the coupling is to be
made and for the particular frequency range of the signals
to be transmitted through the dielectric.
Each spiral (1,2), dielectric substrate (3,4) and
ground plane (8,9) is provided against the opposite faces
of a dielectric layer (5), forming a multi-layer sandwich
with the dielectric layer (5) in the centre and the ground
planes (8,9) on the outer edges.
In use, an RF signal to be transmitted through the
dielectric layer (5) is supplied through a capacitor to one
of the conductive spirals (1,2). Due to the inductive
coupling through the dielectric layer (5), RF signals are
induced in the other conductive spiral (1,2) from where the
signals are output through the second capacitor.
Although not shown in the drawings, the dielectric
substrate (5) may be the plastics wall of an equipment box.
In this case, electrical equipment is provided within the
box, and is connected to one of the conductive spirals
(1,2) which is provided on the inner wall of the box. The
other conductive spiral (1,2) is provided on the outer
surface of the box, and forms the non-contact inductive
coupling between the inside and outside of the box through
which signals are transmitted to and from the equipment
within the box.
A specific example of a coupling according to the
present invention is shown in Figure 2. This is designed
to work at a frequency of 184MHz through a lmm dielectric
wall of polycarbonate. The dielectric substrates (3,4) on
which the conductive spirals (1,2) are formed are also
polycarbonate substrates having a thickness of 2.4mm, and
being approximately 40mm square. The ground plane (8,9) is
formed on the rear of the dielectric substrate (3,4), and
a 10pf capacitor (10) is provided on the same side of the
substrate (3,4) as the ground plane (8,9). Both the
conductive spirals (1,2) and both the ground planes (8,9)
are formed from copper. The capacitor (10) is connected to
the outer end of the spiral (1,2) and the inner end of the
spiral (1,2) is connected to the ground plane (8,9) via
plated through holes (11) extending through the substrate
(3,4). This allows the surface on which the spiral (1,2)
is formed to remain flat. As shown in Figures 3 and 4, the
coupling may be used in conjunction with an antenna (6,7).
In this case the antenna (6,7) is connected directly to one
of the conductive spirals (1,2). Depending on the
particular antenna used, it may or may not be necessary to
include a capacitor to optimise the non-contact coupling,
in particular it is not necessary to include a capacitance
when a monopole antenna is used. An RF signal is applied
to the other conductive spiral (1,2) via an input (12) from
within a housing (13), and this is coupled through the non-contact
inductive coupling to the other conductive spiral
(1,2) and to the antenna (6,7) to transmit the signal.
This system can also be used for reception of the signals
by the antenna (6,7). Figure 3 shows a loop antenna (6)
used in conjunction with the non-contact coupling, and
Figure 4 shows a monopole antenna (7) having a helical
design, although other antennas may be used.
As shown in Figure 5, the non-contact coupling can be
formed as a rotatable coupling. As shown in the Figure,
the dielectric is an air gap. In this case, one of the
ground plates (3) and the associated conductive spiral (1)
are rotatably mounted with respect to the other ground
plate (4) and spiral (2). Due to the spiral design of the
conductive coupling, the relative angular position of the
substrates (3,4) and conductors (1,2) will not affect the
coupling.
Claims (10)
- A non-contact connection through a dielectric (5) comprising a pair of counter-wound conductive spirals (1,2) provided on opposite sides of the dielectric (5), characterised in that a pair of ground planes (8,9) sandwich the conductive spirals (1,2) and the dielectric (5).
- A non-contact connection according to claim 1, further comprising a capacitor (10) provided at the input of each of the spirals (1,2).
- A non-contact connection according to claim 2, in which the connection can be matched by adjusting the capacitance of the capacitor.
- A non-contact connection according to claim 2 or 3, in which the capacitor is a variable capacitor.
- A non-contact connection according to any one of the preceding claims, in which the conductive spirals (1,2) have a rectangular, square or circular configuration.
- A non-contact connection according to any one of the preceding claims, in which the spirals (1,2) are formed onto a substrate (3,4).
- A non-contact connection according to claim 6, in which the ground planes (8,9) are formed on the rear of the substrate (3,4).
- A non-contact connection according to claims 6 or 7, in which a capacitor is printed or otherwise formed on the substrate (3,4) with the conductive spiral (1,2).
- A non-contact connection according to any one of the preceding claims, in which the two counter-wound conductive spirals (1,2) are rotatably provided with respect to each other.
- An antenna assembly comprising a non-contact connection according to any one of the preceding claims, and an antenna connected to one of the conductive spirals (1,2).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9715110 | 1997-07-17 | ||
GB9715110A GB9715110D0 (en) | 1997-07-17 | 1997-07-17 | Coupling |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0892456A1 true EP0892456A1 (en) | 1999-01-20 |
Family
ID=10816026
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98305745A Withdrawn EP0892456A1 (en) | 1997-07-17 | 1998-07-17 | Non-contact coupling through a dielectric |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0892456A1 (en) |
GB (2) | GB9715110D0 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000079644A1 (en) * | 1999-06-17 | 2000-12-28 | Moteco Ab | Antenna device |
WO2000079641A2 (en) * | 1999-06-17 | 2000-12-28 | Moteco Ab | Antenna device |
US7193572B2 (en) | 2002-05-16 | 2007-03-20 | Kathrein-Werke Kg | Roof antenna for motor vehicles |
CN101322144B (en) * | 2005-10-25 | 2012-12-05 | 关卡系统股份有限公司 | Strap member, tag or insert, and method for manufacturing tag or insert |
US20150349612A1 (en) * | 2013-02-12 | 2015-12-03 | Murata Manufacturing Co., Ltd. | Rotating electrical machine |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4621243A (en) * | 1984-12-30 | 1986-11-04 | Harada Kogyo Kabushiki Kaisha | Transmission channel coupler for antenna |
FR2643749A1 (en) * | 1989-02-23 | 1990-08-31 | Dx Antenna | DEVICE FOR COUPLING A HIGH FREQUENCY COAXIAL LINE |
US5105201A (en) * | 1989-06-30 | 1992-04-14 | Harada Kogyo Kabushiki Kaisha | Glass mounted antenna for car radio |
EP0645838A2 (en) * | 1993-09-24 | 1995-03-29 | Nippon Steel Corporation | Non-contact rotating coupler |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0707388B1 (en) * | 1994-10-12 | 2005-12-07 | Dai Nippon Printing Co., Ltd. | Signal transmission device using a fixed and a rotatable body |
-
1997
- 1997-07-17 GB GB9715110A patent/GB9715110D0/en active Pending
-
1998
- 1998-07-17 EP EP98305745A patent/EP0892456A1/en not_active Withdrawn
- 1998-07-17 GB GB9815663A patent/GB2328123A/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4621243A (en) * | 1984-12-30 | 1986-11-04 | Harada Kogyo Kabushiki Kaisha | Transmission channel coupler for antenna |
FR2643749A1 (en) * | 1989-02-23 | 1990-08-31 | Dx Antenna | DEVICE FOR COUPLING A HIGH FREQUENCY COAXIAL LINE |
US5105201A (en) * | 1989-06-30 | 1992-04-14 | Harada Kogyo Kabushiki Kaisha | Glass mounted antenna for car radio |
EP0645838A2 (en) * | 1993-09-24 | 1995-03-29 | Nippon Steel Corporation | Non-contact rotating coupler |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2000079644A1 (en) * | 1999-06-17 | 2000-12-28 | Moteco Ab | Antenna device |
WO2000079641A2 (en) * | 1999-06-17 | 2000-12-28 | Moteco Ab | Antenna device |
WO2000079641A3 (en) * | 1999-06-17 | 2007-11-01 | Moteco Ab | Antenna device |
US7193572B2 (en) | 2002-05-16 | 2007-03-20 | Kathrein-Werke Kg | Roof antenna for motor vehicles |
CN101322144B (en) * | 2005-10-25 | 2012-12-05 | 关卡系统股份有限公司 | Strap member, tag or insert, and method for manufacturing tag or insert |
US20150349612A1 (en) * | 2013-02-12 | 2015-12-03 | Murata Manufacturing Co., Ltd. | Rotating electrical machine |
Also Published As
Publication number | Publication date |
---|---|
GB9715110D0 (en) | 1997-09-24 |
GB2328123A (en) | 1999-02-10 |
GB9815663D0 (en) | 1998-09-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR100270793B1 (en) | Coaxial cable coupling device and antenna device | |
EP1652270B1 (en) | Slotted cylinder antenna | |
US6304220B1 (en) | Antenna with stacked resonant structures and a multi-frequency radiocommunications system including it | |
CA1195771A (en) | Tuned small loop antenna with wide frequency range capabilities and method for designing thereof | |
US4395713A (en) | Transit antenna | |
EP1202382B1 (en) | Antenna | |
US6218990B1 (en) | Radiocommunication device and a dual-frequency microstrip antenna | |
US6384793B2 (en) | Slot antenna device | |
US4740794A (en) | Connectorless antenna coupler | |
EP0608992A1 (en) | Dual purpose, low profile antenna | |
KR20010075231A (en) | Capacitively-tune broadband antenna structure | |
WO2001063695A1 (en) | Compact, broadband inverted-f antennas with conductive elements and wireless communicators incorporating same | |
KR20100068480A (en) | Co-location insensitive multi-band antenna | |
GB2293050A (en) | An antenna used for the transmission or the reception of a radio frequency signal, a transmitter and a remote control receiver. | |
US5867130A (en) | Directional center-fed wave dipole antenna | |
US5945950A (en) | Stacked microstrip antenna for wireless communication | |
WO1994024723A1 (en) | A small, double ring microstrip antenna | |
WO1994024722A1 (en) | Small microstrip antenna having a partial short circuit | |
US5497167A (en) | Antenna for mounting on a vehicle window | |
KR19980702904A (en) | Dual frequency antenna with integrated diplexer | |
EP0892456A1 (en) | Non-contact coupling through a dielectric | |
US8199056B2 (en) | Antenna arrangement | |
US6359593B1 (en) | Non-radiating single slotline coupler | |
KR100294189B1 (en) | Wireless telephone-embedded microstrip patch antenna | |
US20020000946A1 (en) | Antenna feed structure |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
|
AX | Request for extension of the european patent |
Free format text: AL;LT;LV;MK;RO;SI |
|
AKX | Designation fees paid | ||
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 19990721 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: 8566 |