DE2201814A1 - Filter connection arrangement - Google Patents

Description

Dr. phil. G. B. HAGEN Patent attorney

BOOO MUNICH 71 (Solin) 2 2 0 I 9 |

Franz-Hals-Strasse 21
Telephone 796213

AMP 3007 Munich, I3. January 1972

NS

AMP Incorporated

Eisenhower Boulevard

Harrispurg, P a ο, V. St ₀ A.

Filter connector assembly

Priority: 2g. Jan. 1971J V.St.A. · ,. No. IO9 423

The invention relates to electrical connector assemblies in which a connector part has one or more contact terminals carries and a second, with the first connectable connector part carries complementary contact terminals, so that when the connector parts are connected, one or more electrical circuits result. In particular, relates calibrates the invention to a connector assembly in which High-frequency filter with capacitive, inductive and / or lossy circuit elements electrically with the Terminals of one of the connector parts are connected in such a way that that unwanted high frequency signals are attenuated.

Terminal pins, which form the contact elements, are inserted into the high-frequency filter to form electrical contact with the filter generally inserted on the inside by means of soldering or by using a contact spring device The filter is also connected to earth, usually on the outside and through the metal shell of the connector housing. When the filter is installed in an electrical device, this metal shell is connected to the earth

Bavarian Vereinibank Mündien 820993

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circuit of the device in question. In this way, for undesired high-frequency signals, the Frequencies above 1.0 GHz and up to 10 GHz or more can have a low resistance route.

The performance of a filter connector assembly depends in large part on the internal shunt impedance of the filter as well as the impedance of the circuit with earth return associated with the filter · At higher frequencies, the equivalent shunt impedance of the filter is very small, usually less than one milliohm. On the other hand, the impedance of the circuit with the earth pressure line increases, the one very having small inductance in series with a resistor, with increasing frequency »this results from the increased Reactance of the inductance inherent in the circuit with earth return and also from the skin effect of the conductive surface. At frequencies above 1.0 GHz, the Performance of the filter also from the circuit with earth return as from the filter itself.

In addition to the series inductance and resistance contained in the ground plane, the outer surface or the A filter's earth circuit also has a residual impedance in the form of inductance and series resistance, which are added to those of the feedback loop and vary at frequencies make this particularly noticeable above 3 »0 GHz.

The traditional method of creating a ground return uses a sheet metal ground plane at a right angle to the axis of the connector pins, or alternatively one made of conductive Rubber grounding surface provided. Although such a grounding method provides satisfactory performance for some applications, performance at high frequencies leaves much to be desired. In particular, the impedance of a circuit with earth

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return line, in which a single conductive ground plane is used at high frequencies too high to get optimal performance · In addition, the Series inductance and the resistance of the filter earth circuit itself, usually the outer surface of the filter, at high Frequencies interfering with · The impedance of a single surface can be kept very small by application a thickness that is at least equal to two skin depths at the The lowest frequency used is · Although a certain hatred of mechanical stability can be achieved are made by using a grounding surface of greater thickness, but the impedance of the earth circuit is not reduced, and there is no improvement in electrical performance by using this greater thickness.,

It is the object of the invention to provide an improved filter connector to arrange

A filter connector assembly having an electrically conductive pin, one electrically connected to the pin Filter element and a connector pin and the filter element supporting housing, which is an electrical having conductive sheath and an electrically conductive grounding surface, the latter of which extends from a conductive layer of the filter extends to the envelope, is characterized according to the invention by at least one further electrically conductive Ground plane spaced from the first ground plane and extending socn from the filter element to the envelope.

Embodiments of the invention are described below with reference to the figures. From the figures demonstrate:

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Figure 1 is a section through a known filter connector assembly ;

Figure 2 shows a section through an inventive Filter connector assembly;

FIG. 3 shows an enlarged illustration of part of FIG The connector assembly of Figure 2;

Figure 4 is a schematic diagram of the connector assembly according to Figure 1;

Figure 5 is a schematic circuit diagram of the connector arrangement according to Figure 2)

FIG. 6 is a diagram showing filter performance curves including the filter performance curves of FIG Connector arrangements according to Figures 1 and 2 $ and

FIG. 7 shows a section through a modified embodiment of the invention.

In a typical filter connector arrangement according to the figure, connecting pins 10 and surrounding tubular filter elements 12, which are connected to the pins 10 by contact springs (not shown), are held in a housing Ik which has a conductive sheath 15 which is connected to a grounded holder , whereby the arrangement is earthed. The connector assembly also includes a front insulator 16, a rear insulator 18, a ground plane 20, and a grommet 22. The ground surface is enclosed between the front insulator 16 and the rear insulator 18 perforations 19 in the ground surface 20 are aligned with openings 21 which penetrate the front insulator 16, the rear insulator 18 and the grommet 22 and receive the pins 10 having the filter elements. The grounding surface 20 has prongs 2k formed in one piece with it, which form contact with the metal shell 15, and identically formed prongs 26 on the perforations 19 in the grounding surface 20, which form contact with the outer or grounding surfaces of the filter elements 12. This creates a filter circuit that

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Has input and output terminals formed by the ends of the pins 10 and a ground connection formed by the metal shell 15 and the ground plane _{or the like}

The filter connector arrangement according to the invention shown in FIG is designed similar to that of Figure 1, but has an additional insulator, i. ho the intermediate insulator 28, on and a pair of parallel, spaced apart grounding surfaces 30 in place of the only one Grounding surface 20. By using two grounding surfaces 30, the impedances of the earth return circuits for the filter elements 12 are reduced, and the effect of the residual impedances the filter earth circles on the outer surfaces of the filter elements 12 is kept low.

The use of two grounding surfaces 30 results longitudinally spaced filter supports along each filter element 12 on the prongs 26 both grounding surfaces 3 ° contribute to the filter arrangement to keep rigidly in place, reducing the radial stress on the filter elements 12 that results when the pin 10 is inadvertently bent during handling or use of the assembly, greatly reduced. As a result of this reduced stress, the filter elements will also largely break avoided. In addition to the mechanical support created on the prongs 26, a certain amount of support is obtained Redundancy in the ground connection which increases the reliability factor of the filter connector assembly. aside from that it has been shown that the assembly of the front insulator l6 and the rear insulator l8 by the use of two grounding surfaces 30 is facilitated.

Figure 3 shows the nature of each filter element 12, which is a tubular dielectric 32, an outer conductive one

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Layer Jk on the outer or grounding surface of the dielectric 32 and a conductive ferrite sleeve 40 which has an axial opening for receiving the terminal pin 10 to form electrical contact between the pin 10 and the filter. The preferred embodiment of the filter element 12 is described in detail in the German patent application P 20 58 419 »4 of the applicant.

Figure 4 is a schematic diagram of the filter connector assembly of Figure 1 with only one grounding surface. The circuit has an input terminal 4l, an output terminal 42, a ground point 44, a filter 46, and a ground return circuit 48. The induction resistance path between the input terminal 4l and the output terminal 42 has an induction coil 30 and a resistor 52, which is formed by the pin 10 and the ferrite sleeve 40 and corresponds to these. The capacitors 54 and 56 set represents the capacitive paths between terminals 41 and 42 and the outer conductive layer 34. In series with resistors 62 and 64 lying induction coils 58 and 60 form the Filter earth circuit or induction resistance path along the outer conductive layer 34, the induction coil 58 and resistor 62, the induction resistance path on one side of the single ground plane 20 and the induction coil 60 and the resistor 64 represent the induction resistance path on the other side of the grounding surface 20 As a result, the earth return circuit 48, which has a series induction resistance path with an induction

coil / and a resistor 68, between the connection point of the induction coil 58 and the resistor 62 or the induction coil 60 and the resistor 64 combinations and earth 44 connected.

The use of a plurality of grounding surfaces means that the impedance of the ground return circuit as well as the effect of the impedance of the filter ground circuit are very small.

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will hold. This is clearly seen from the schematic diagram of Figure 5 _o

As FIG. 5 shows, the residual impedance of the outer layer 34 has been divided into three different ones lying in series inductive paths with induction coils 70, 72, 74 and Resistors 76, 78 and 8O. Since the earth return circuit is two Has separate grounding surfaces 3O, contains the earth return circuit 82 a first induction resistance path in series with an induction coil 84 and a resistor 86 and a second induction resistance path with an induction coil 88 and a resistor 90 »through Creation of a distance between the earth surfaces which is considerable in relation to the thickness of the thin earth surfaces 30 is the impedance of induction coil 72 and resistor 78 considerable, and the impedance of the induction coils 70 and 74 and resistors 76 and 80 increases accordingly so that the effect of the residual impedance of the filter earth circuit is kept very small. Since, in addition, the earth return circuit 82 has two branches, as Figure 5 shows, the resulting impedance is considerably reduced, and as a result, the performance of the filter is increased accordingly. This is to be compared with the significant effect of the residual impedance of the filter ground circuit 34 created by inductors 58 and 60 and the resistors 62 and 64 of the known arrangement shown in Figure 4 is represented, as well as the high one. Impedance of the earth return circuit, which has only one, the induction coil 66 and the resistor 68 Branch hatο

You can therefore see that by using two grounding surfaces instead of one, the impedance of the ground return circuit is reduced by at least 50%

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Impedance of the ground plane is small. In addition, the effect of the resistance resulting from the filter earth circuit in the form of the outer layer "} k can be reduced considerably, since the voltage appearing across the induction coil 8k and the resistor between the induction coils 72 and 88 and the resistors 78 and 90 must be divided.

It can now be seen that the distance between the ground planes 30 and the connection to the outer conductive layer in different and mutually spaced areas is very important, as this is the height of the represented by induction coil 72 and resistor 78 Impedance affected. It has been found that an increase in the distance between the grounding surfaces by about 1.58 mm the insertion loss of the filter im very can increase the high frequency range by 3 dB. You also have found that by using two in mutual electrical contact standing grounding surfaces results in a performance of the filter that is essentially is identical to the performance of a filter arrangement in which only a single grounding surface is used finds. It is evident that further improvements in the performance of the filter are effected can by providing more than two grounding surfaces (Figure 7).

Figure 6 shows a number of performance curves which are different Filter connector assemblies, with insertion losses plotted against frequency. the first curve from bottom to top is that of a filter connector assembly with a single metallic grounding surface, the second curve is that of a filter connector assembly with a single, 1.58 mm thick grounding surface made of conductive rubber, the third curve is that of a filter with a double metallic ground plane, and the fourth curve is that of a filter connector assembly with

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coaxial holding device. The curve of each metal ground plane represents the performance of the filter connector assembly according to Figure 1 using a 0.0762 mm thick and 6 prongs having silver-plated Beryllium copper ground plane. As shown in Fig. 6, the insertion loss reaches even at low levels Frequencies never 70 dB. The curve characteristic of a filter connector assembly having one made of conductive rubber existing, 1.58 mm thick grounding surface is used, shows slightly better performance. The maximum launch loss However, it is only 80 dB, and this is contrasted only at frequencies in the range of 0.7 GHz in addition, with the performance of the filter connector arrangement according to FIG. 2, in which two 0.0762 mm thick, 6 prong silver plated beryllium copper ground planes are used, which are spaced from one another in the manner shown, there is an insertion loss from about 85 dB over frequency ranges from 0.2 to nearly 3.0 GHz. Even with a value of Higher frequencies approaching 10.0 GHz is the performance of the connector having two metallic ground planes far better than that of the connector with the ground plane. made of conductive rubber or the connector with the only one metallic grounding surface. As you can see, the Performance improved by a factor of approximately 10 dB.

The last curve shown is that of a filter connector mounted in a coaxial support arrangement. These Curve shows near optimal performance with an insertion loss greater than 85 dB over a range from 0.3 to 10.0 GHz. Of course there is such a thing Filter connector assembly for the reasons outlined above impractical. It is significant that the connector assembly having two metallic ground planes is over has near optimal performance over a considerable frequency range. The performance of the connector assembly with

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two metallic ground planes can be improved by using additional ground planes. Naturally the use of additional grounding surfaces would only come in question for critical high-frequency applications, since the insertion loss of an arrangement with two metallic grounding surfaces is almost 6O dB at 10 GHz.

Patent claims:

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Claims (6)

AMP 3OO7 -Z- Patent claims I ^ filter connector assembly with an electrically conductive Connector pin, one electrically connected to the connector pin Filter element, a connector pin and the filter element supporting housing, which is an electrical having conductive sheath and an electrically conductive grounding surface, the latter of which extends from a conductive layer of the filter extends to the sheath, characterized by at least one further electrically conductive one Grounding surface (30) which is at a distance from the first grounding surface (30) and which extends from the filter element (12) extends to the sheath (15). 2. Filter connector arrangement according to claim 1, characterized in that the grounding surfaces (30) are isolated with respect to one another by insulators (16, 18, 28) extending from the filter element (12) to the sheath (15). 3. Filter connector assembly according to claim 1 or 2, characterized in that each of the Ground planes (30) is thin with respect to the distance (28) between the ground planes (30). 4. Filter connector arrangement according to one of claims 1-3 » characterized in that each grounding surface (30) consists of a thin sheet of metal. 5. Filter connector assembly according to any one of claims 1-4, wherein the filter element is tubular and has an outer conductive layer and an axial bore that receives the pin and with this electrical contact forms, characterized in that 209834/0671 AMP 3OO7 -T2 - 22018H that the grounding surfaces (30) are enclosed between insulators (l6, 18, 28) and that the insulators (l6, l8, 28) and the grounding surfaces (30) have aligned openings (19 and 21) which connect the pin (10) and accommodate the filter element (12). 6. filter connector assembly according to claim 5, characterized in that each He extension surface (30) contact prongs formed in one piece with it (24) extending laterally from the ground plane (30) and on the outer conductive layer Attack the filter element (12) 209834/0671 Blank page