Title of Invention

METHOD FOR HIGH-FREQUENCY TUNING AN ELECTRICAL DEVICE, AND A PRINTED CIRCUIT BOARD THEREFOR.

Abstract A method for RF matching of an RF plug connector (1), having a printed circuit board (3), with the printed circuit board having contact points (21-28) for RF contacts and contact points (31-38) for insulation-displacement contacts, with one contact point (21-28) for the RF contacts in each case being connected to a respective contact point (31-38) for the insulation-displacement contacts,and with capacitive coupling, which causes near-end crosstalk, occurring between the RF contacts, characterized in that at least one first conductor track (46), which is connected on only one side to a contact point (26) of circuit board (3) and, together with at least one second conductor track (44) which is arranged on and/or in the printed circuit board (3), forms a capacitor (C46), with at least one frequency-dependent parameter of the arrangement being measured, the frequency-dependent parameter being compared with a nominal parameter, and the conductor track (46) with which contact is made on one side being partially removed or cut through as a function of the difference.
Full Text The invention relates to a method for RF matching of an electrical of an electrical
arrangement, and to a printed circuit board which is suitable for this purpose.
Disclosure of US 6,023,200 dated February 06,2000 (Rhee) is hereby
incorporated by way of reference.
EP 0 525 703 A1 discloses a plug connected for computer networks in the
domestic area, comprising a male connector part and a female connector part,
with a device for crosstalk compensation being arranged in the plug connection,
by means of which the crosstalk attenuation between the transmission
conductor loop and the reception conductor loop can be increased. For this
purpose, a printed circuit board is arranged in the female connector part or in
the male connector part of the plug connection between the connections for the
plug-in cable and the connections for the wiring, with the conductor routes for
the transmission and reception conductor loops being largely physically
separated on the printed circuit board. The devices for crosstalk compensation
are, for example, discrete components such as capacitors or coils, which are
adjustable . The known plug connection has the disadvantage that the discrete
components are relatively expensive and large.
DE 100 51 097 Al discloses an electrical plug connector comprising a plug
connector housing, a printed circuit board with two sets of contact elements,
with the first set of contact elements being arranged on the front face of the
printed circuit board and projecting into an opening in the plug connector
housing, and the second set of contact elements being arranged on the rear face
of the printed circuit board, and the contact elements in the second set being in
the form of insulation-displacement contacts, with the plug
connector having a cable manager which has an opening
through it and is provided on the front face with
guides for conductors which are intended to make
contact with the insulation-displacement contacts, with
the guides being formed in the area of the insulation-
displacement contacts with recessed holders for the
insulation-displacement contacts, and in which case the
cable manager can be matched to the plug connector
housing.
Owing to the increasing bandwidth for data transmission
in telecommunications and information technology, the
conductors, contacts and conductor tracks have to be
designed such that they are highly defined with respect
to one another, in order to comply with the required
values for the crosstalk attenuation.
This necessitates extremely tight tolerances, which can
be complied with only with difficulty during automated
manufacturing processes.
The invention is thus based on the technical problem of
providing a method for matching an RF plug connector,
in particular an RJ-45 female connector, having at
least one printed circuit board, with the printed
circuit board having contact points for RF contacts and
contact points for the insulation-displacement
contacts, and with one contact point for the RF
contacts in each case being connected to a respective
contact point for the insulation-displacement contacts,
and a printed circuit board which is suitable for this
purpose and by means of which the RF characteristics
can be adjusted within a narrow tolerance band.
The technical problem is solved by the subject matters
with the features of patent claims 1 and .11. Further
advantageous refinements of the invention are described
in the dependent claims.
For this purpose, at least one first conductor track,
which is connected on only one side to a contact point
of an electrical contact, is arranged on the printed
circuit board and, together with at least one second
conductor track which is arranged on or in the printed
circuit board, forms a capacitor, with at least one
frequency-dependent parameter of the arrangement being
measured, the frequency-dependent parameter being
compared with a nominal parameter, and the conductor
track with which contact is made on one side being
partially removed or cut through as a function of the
difference, This makes it possible to form a matchable
capacitor using simple and cost-effective means, and by
means of which the RF response of the arrangement can
be matched. The conductor tracks are in this case
preferably connected to the contact points of the RF
contacts, since this means that the matching
capacitances are closer to the location of the source
of the crosstalk. However, in principle, they may also
be connected to the contact points of the insulation-
displacement contacts, which are electrically connected
to the contact points of the RF contacts. It should be
noted that, in principle, it is sufficient to cut
through or to remove one conductor track of a capacitor
in order to change the capacitance.
The opposite electrode of the capacitor is preferably
likewise formed by a conductor track that is connected
to a contact point on one side.
In a further preferred embodiment, at least one further
second conductor track is"" arranged in an internal layer
in the printed circuit board and is electrically
connected to the conductor track on the printed circuit
board. This represents capacitances " connected in
parallel, so that the total capacitance is added, thus
allowing the formation of a sufficiently large
capacitance on a relatively small area.
In a further preferred embodiment, at least two
independent capacitors which are formed by. conductor
tracks are arranged on the printed circuit board, in
order to carry out symmetrical trimming with respect to
ground.
In a further preferred embodiment, the frequency-
dependent parameter is determined and adjusted on the
unpopulated printed circuit board. This is based on the
knowledge that, particularly in the case of RF plug
connectors, the printed circuit board itself is
responsible for the majority of the RF tolerances.
These tolerances are generally geometric tolerances of
the layout elements, such as conductor tracks, and
tolerances of the dielectric constant of the material
of the printed circuit board. Automatic measurement on
an unpopulated printed circuit board is considerably
easier than on a populated printed circuit board, or
even on a printed circuit board that has been installed
in a housing. The overall arrangement can thus be
matched even at an early stage in the process of
producing the printed circuit board. The feed and
measurement are in this case preferably provided
centrally in soldered eyes of the contact points.
In a further preferred embodiment, only a portion of
the estimated conductor track shortening that is
necessary is carried out in a first step. The
frequency-dependent parameter is then measured once
again. The measured change is then used to determine
the remaining conductor track length that is still to
be removed or to be cut. This also takes account of the
tolerances relating to the conductor tracks in the
matching process. The conductor track shortening can in
this case also be subdivided into more than two steps.
In a further preferred embodiment, the final cut during
the cutting of the conductor track is carried out in a
broader manner than the first cut. This broader cut
minimizes the capacitive influence of the cut part of
the conductor track.
In a further preferred embodiment, the near crosstalk
is determined as the frequency-dependent parameter,
thus making the matching process easier, since the
parameter to be optimised directly is determined, so
that there is no need for any further estimates of the
influence of the parameter on the near crosstalk as
would be the case, for example, with pure capacitance
measurement.
The conductor track is preferably cut by means of a
laser,preferably by means of a short-wave laser with a
wavelength that is shorter than 600 nm. The use of a
laser for cutting the conductor track is extremely
fast, and can easily be automated. In principle, the
conductor track can also be cut or removed
mechanically, for example by means of milling or
electrically by using an overcurrent to burn through
it.
In a further preferred embodiment, the laser has an
associated optical positioning system. This results in
the conductor track being cut in a more defined manner,
without any damage to closely adjacent conductor tracks
and without the conductor track to be cut not being cut
completely.
During removal or cutting of the conductor track, it is
possible for copper particles to be deposited on the
printed circuit board, and these in turn reduce the
resistance to overvoltages. The cutting or removal of
the conductor track is thus preferably followed by a
cleaning step to remove the copper particles and/or any
other contamination.
The invention will be explained in more detail in the
following text with reference to a preferred exemplary
embodiment. In the figure:
Figure 1 shows an exploded illustration of a plug
ponnector for transmitting RF data (prior
art),
Figure 2 shows a printed circuit board for use in a
plug connector shown in Figure 1,
Figure 3 shows a schematic equivalent circuit, for the
printed circuit board,
Figure 4 shows a schematic frequency response for the
near crosstalk and
characteristics
Figure 5 shows a family of for the attenuation
D of the near crosstalk as a function of the
length of the conductor track to be removed.
Figure 1 shows an exploded illustration of a plug
connector 1. The plug connector 1 has a plug connector
housing, 2, a printed circuit board 3, a hold-down
device 4 and a cable manager 5. The plug connector
housing 2 in the illustrated example is in the form of
a female connector housing with various latching and
insertion means. The plug connector housing 2 has a
shielding plate 6 on the side surfaces. The printed
circuit board 3 is fitted on its front face with a
first set of contacts 7, and is fitted on its rear face
with a second set of insulation-displacement contacts
8. One contact 7 in the first set is connected to a
respective contact 8 in the second set. The printed
circuit board 3 is then inserted into the plug
connector housing 2. In the process, cylindrical pins 9
of the plug connector housing 2 pass through holes in
the printed circuit board 3, so that the plug connector
housing 2 and the printed circuit board 3 are adjusted
and fixed with respect to one another. The contacts 7
(which are in the form of RF contacts) in the first set
then project into an opening which is accessible from
the front face of the plug connector housing. The hold-
down device 4 is then pushed over the contacts 8 in the
second set, and is latched to the plug connector
housing 2. For this purpose, the hold-down device 4 has
latching tabs 10 on the end face, and has openings 11
through it for the insulation-displacement contacts 8.
Furthermore, the hold-down device 4 has two latching
hooks 12, which are used for latching to the cable
manager 5.
Figure 2 shows the unpopulated printed circuit board 3.
The printed circuit board 3 has eight contact points
21 - 28 and contact holes for the RF contacts, and
eight contact points 31 - 38 for the insulation-
displacement contacts. The printed circuit board 3 also
has further plated-through holes 40 for connection of
conductor tracks on the front face and rear face and
internal layers in the printed circuit board, with the
plated-through holes 40 being illustrated as small
circles. The holes 41 in the printed circuit board 3
are in this case illustrated as small squares. The
conductor tracks which connect the contact points 21 -
28 to their respectively associated contact point 31 -
38 are not shown, with the exception of two parts of
the contact points 24 and 35 since they are arranged on
the rear face and/in the internal layers of the printed
circuit board. In addition to the electrically
connected conductor tracks between two contact points
21 - 28 and 31 - 38, respectively, there are also four
conductor tracks 43 - 46 which are respectively
connected on one side to a contact point 23 - 26. In
this case, the two conductor tracks 44 and 46 form a
capacitor between the contact points 24 and 26. In a
corresponding way, the two conductor tracks 43 and 45
form a capacitor between the contact points 23 and 25.
A further conductor track is preferably arranged in an
internal layer, is electrically connected to conductor
track 44, and is located under the conductor track 46.
For circuitry purposes, the contact points 21, 22; 23,
26; 24, 25 and 27, 28 and their respectively associated
contacts form a contact pair. In this case, the two
outer contact pairs 21, 22 and 27, 28 are relatively
uncritical with regard to near crosstalk. The two inner
and interleaved contact pairs 23, 26 and 24, 25, on the
other hand, are problematic. The capacitances which
cause disturbances in this case are located between 23
and 24 as well as between 25 and 26, since the other
couplings are negligible, owing to the greater
distances between them.
Figure 3 shows the resultant equivalent circuit,
including the schematic test layout. In this case, the
capacitors C46 and C35 essentially represent capacitors
formed by the conductor tracks 44 and 46 as well as 43
and 45, respectively, while, in contrast, the
capacitors C34 and C56, respectively, are formed by the
adjacent contact points 23, 33 as well as the
associated conductor track, 24, 34 with the conductor
track as well as 25, 35 with the conductor track, and
26, 36 with the conductor track. This bridge circuit
can now be trimmed in order to force the near crosstalk
below the required values. Before the trimming process,
the asymmetry is first of all determined by determining
the near crosstalk of one contact pair as a frequency-
dependent parameter. In the present case, crosstalk is
determined between the contact pair 23, 33 and 26, 36
and the contact pair 24, 34; 25, 35. Since the
measurement is preferably carried out on the
unpopulated printed circuit board 3, the contact points
33 - 36 are terminated with the correct impedance. The
near crosstalk to the contact points 25, 24 is then
measured, with RF signals being injected into the
contact points 23, 26, by means of a network analyzer
which is symbolized in Figure 3 by the frequency
generator 50 and the measurement device 51. The feeding
and measurement of the RF signals are in this case
provided by means of a central contact in the solder
eyes of the contact points 23 - 26.
Figure 4 schematically shows the frequency response of
the near, crosstalk NEXT, with the profile a
representing nominal near crosstalk, and the profile b
representing the measured actual near crosstalk for a
measured printed circuit board. The nominal near
crosstalk is determined, for example, by means of a
golden device. In this case, the measured near
crosstalk is too high by an amount A NEXT, so that this
must be compensated for by shortening the conductor
tracks, thus reducing the capacitance. The measure of
how many millimeters of conductor track correspond to
what capacitance and thus to the near crosstalk
attenuation D depends on the tolerances of the printed
circuit board, such as the dielectric constant or the
distance between the conductor tracks. There is
therefore no single straight line, but an entire family
of characteristics, as is illustrated schematically in Figure 5.
Since the tolerances are unknown, it may first of all
characteristics
be necessary to determine which characteristics is applicable to
the printed circuit board to be matched. For this
purpose, a piece of conductor track is first of all
removed or cut through, and the measurements are then
carried out once again. The increase in the attenuation
D that is found can then be used to determine the
associated characteristics. If, on the other hand, the desired
attenuation is greater than that which can be achieved
with the steepest Iradient, the entire conductor track can
be removed or cut through without any intermediate
step. The method is then repeated on the other
capacitor.
The conductor track is preferably cut through by means
of a short-wave laser, whose power and focusing are
matched to the copper track to be cut such that, as far
as possible, this is all that is removed. The advantage
of a laser is its high speed with good reproducibility,
so that the matching process can easily be automated.
List of reference symbols
1) Plug connector
2) Plug connector housing
3) Printed circuit board
4) Hold-down device
5) Cable manager
6) Shielding plate
7) Contacts
8) Contacts
9) Cylindrical pins
10) Latching tabs
11) Openings
12) Latching hook
21) Contact points (for RF contacts)
22) Contact points (for RF contacts)
23) Contact points (for RF contacts)
24) Contact points (for RF contacts)
25) Contact points (for RF contacts)
26) Contact points (for RF contacts)
27) Contact points (for RF contacts)
28) Contact points (for RF contacts)
31) Contact point (for an insulation-displacement
contact)
32) Contact point (for an insulation-displacement
contact)
33) Contact point (for an insulation-displacement
contact)
34) Contact point (for an insulation-displacement
contact)
35) Contact point (for an insulation-displacement
contact)
36) Contact point (for an insulation-displacement
contact)
37) Contact point (for an insulation-displacement
contact)
38) Contact point (for an insulation-displacement
contact)
40) Plated-through hole
41) Hole
43) Conductor track
44) Conductor track
4 5) Conductor track
4 6) Conductor track
50) Frequency generator
51) Measurement device
1. A method for RF matching of an RF plug connector
(1), having a printed circuit board (3), with the
printed circuit board having contact points (21-28) for
RF contacts and contact points (31-38) for
insulation-displacement contacts, with one contact
point (21-28) for the RF contacts in each case being
connected to a respective contact point (31-38) for the
insulation-displacement contacts, and with capacitive
coupling, which causes near-end crosstalk, occurring
between the RF contacts,
characterized in that
at least one first conductor track (46), which is
connected on only one side to a contact point (26) of
an electrical contact, is arranged on the printed
circuit board (3) and, together with at least one
second conductor track (44) which is arranged on and/or
in the printed circuit board (3), forms a capacitor
(C46), with at least one frequency-dependent parameter
of the arrangement being measured, the frequency-
dependent parameter being compared with a nominal
parameter, and the conductor track (46) with which
contact is made on one side being partially removed or
cut through as a function of the difference.
2. The method as claimed in claim 1, characterized in
that the second conductor track (44) is in the form of
a conductor track (44) with which contact is made on
one side.
3. The method as claimed in claim 1 or 2,
characterized in that at least one further second
conductor track is arranged in an internal layer in the
printed circuit board (3) and is connected to the
second conductor track (44) that is arranged on the
printed circuit board (3).
4. The method as claimed in one of the preceding/
claims, characterized in that at least two matchable
capacitors (C46, C35) are arranged on the printed circuit|
board (3).
5. The method as claimed in one of the preceding
claims, characterized in that the frequency-dependent
parameters are determined on the unpopulated printed
circuit board (3).
6. The method as claimed in one of the preceding!
claims, characterized in that in a first step, only a
portion of the estimated conductor track shortening (L)
that is necessary is carried out, the frequency-
dependent parameter is "measured once again, and the
remaining conductor track length which is still to be
removed or to be cut is determined from this.
7. The method as claimed in claim 6, characterized in
that, in the final step, the conductor track (46, 45)
is cut in a broader manner than in the first step.
8. The method as claimed in one of the preceding
claims, characterized in that near crosstalk (NEXT) is ;
determined as the frequency-dependent parameter.
9. The method as claimed in one of the preceding
claims, characterized in that the conductor track (46,
45) is cut by means of a laser.
10. The method as claimed in one of the preceding
claims, characterized in that the process of
controlling the laser is assisted by means of an
optical system.
11. A printed circuit board for holding RF contacts
and insulation-displacement contacts for an RF plug
connector, with the printed circuit board having eight
contact points (21-28) for RF contacts and eight
contact points (31-38) for insulation-displacement
contacts, with one contact point (21-28) for the RF
contacts in each case being connected to a respective
contact point (31-38)for the insulation-displacement
contacts, and with capacitive coupling which causes
near-end qrosstalk occurring between the RF contacts,
characterized in that
at least one first conductor track (46), which is
connected on only one side to a contact point (26) of
an electrical contact, is arranged on the printed
circuit board (3)and, together with at least one
second conductor track (44) which is arranged on and/or
in the printed circuit board (3) , forms a capacitor
(C46).
12. The printed circuit board as claimed in claim 11,
characterized in that the second conductor track (44)
is likewise a conductor track (.44) which is connected
to a contact point (24) on one side.
13. The printed circuit board as claimed in claim 11
or 12, characterized in that at least one further
second conductor track is arranged in an internal layer
in the printed circuit board (3) and is connected to
the further conductor track (44) that is arranged on
the printed circuit board (3).
14. The printed circuit board as claimed in one of
claims 11 to 13, characterized in that at least two
matchable capacitors (C46, C35) are arranged on the
printed circuit board (3).
15. The printed circuit board as claimed in one of
claims 11 to 14, characterized in that the first
capacitor (C46) is arranged between the contact points
(24 and 26), and the second capacitor (C35) is arranged
between the contact points (23 and 25).
A method for RF matching of an RF plug connector (1), having a printed circuit
board (3), with the printed circuit board having contact points (21-28) for RF
contacts and contact points (31-38) for insulation-displacement contacts, with
one contact point (21-28) for the RF contacts in each case being connected to a
respective contact point (31-38) for the insulation-displacement contacts,and
with capacitive coupling, which causes near-end crosstalk, occurring between the
RF contacts, characterized in that at least one first conductor track (46), which is
connected on only one side to a contact point (26) of circuit board (3) and,
together with at least one second conductor track (44) which is arranged on
and/or in the printed circuit board (3), forms a capacitor (C46), with at least one
frequency-dependent parameter of the arrangement being measured, the
frequency-dependent parameter being compared with a nominal parameter, and
the conductor track (46) with which contact is made on one side being partially
removed or cut through as a function of the difference.

Documents:

01690-kolnp-2005-abstract.pdf

01690-kolnp-2005-claims.pdf

01690-kolnp-2005-description complete.pdf

01690-kolnp-2005-drawings.pdf

01690-kolnp-2005-form 1.pdf

01690-kolnp-2005-form 2.pdf

01690-kolnp-2005-form 3.pdf

01690-kolnp-2005-form 5.pdf

01690-kolnp-2005-international publication.pdf

1690-KOLNP-2005-(12-01-2012)-FORM 27.pdf

1690-kolnp-2005-granted-abstract.pdf

1690-kolnp-2005-granted-claims.pdf

1690-kolnp-2005-granted-correspondence.pdf

1690-kolnp-2005-granted-description (complete).pdf

1690-kolnp-2005-granted-drawings.pdf

1690-kolnp-2005-granted-examination report.pdf

1690-kolnp-2005-granted-form 1.pdf

1690-kolnp-2005-granted-form 18.pdf

1690-kolnp-2005-granted-form 2.pdf

1690-kolnp-2005-granted-form 26.pdf

1690-kolnp-2005-granted-form 3.pdf

1690-kolnp-2005-granted-form 5.pdf

1690-kolnp-2005-granted-reply to examination report.pdf

1690-kolnp-2005-granted-specification.pdf

1690-kolnp-2005-granted-translated copy of priority document.pdf

abstract-01690-kolnp-2005.jpg


Patent Number 224445
Indian Patent Application Number 01690/KOLNP/2005
PG Journal Number 42/2008
Publication Date 17-Oct-2008
Grant Date 14-Oct-2008
Date of Filing 24-Aug-2005
Name of Patentee ADC GMBH
Applicant Address BEESKOWDAMM 3-11, NO. 14167 BERLIN, GERMANY
Inventors:
# Inventor's Name Inventor's Address
1 BRESCHE, PETER TEGELER WEG 3, 10589 BERLIN, GERMANY
2 HETZER, ULRICH ZUHLSDORFOR STR. 39, 13679 BERLIN, GERMANY
PCT International Classification Number H05K 1/02, 3/02
PCT International Application Number PCT/EP2004/001952
PCT International Filing date 2004-02-27
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10310434.8 2003-03-11 Germany