DE202010013616U1 - High-frequency test probe - Google Patents

Abstract

High-frequency test pin (8) for releasably contacting a high-frequency contact partner (30) having an inner and an outer contact, in particular a high-frequency contact socket or plug or a contacting point on a printed circuit board, with a coaxially formed, one-way contacts (12) for the high-frequency contact Contact partner (30) offering arrangement of an outer conductor (16) and a relative thereto in the axial direction resiliently guided inner conductor (14), the other ends (10) are externally contacted, characterized in that in a formed by the outer conductor (16) cavity ( 21) an attenuator (22) is provided which contacts the inner and outer conductors to realize a predetermined attenuation effect on a transmitted and / or reflected input signal at contact portions (25, 27).

Description

The The invention relates to a high frequency test pin according to the preamble of the main claim. Furthermore, the present invention relates to a RF test set with at least one such test pin.

Out In the prior art are pins as test pins for contacting a electrically measured product in the test field or quality control known for decades. Thereby contact pins (test pins) play an important role, because they provide, often with the help of feathers or the like power storage flexibly supports the electrical connection from an electrical test infrastructure to a test object. Critical is besides the mechanical Resilience and fitness for a variety of inspection procedures in particular also a safe electrical contact.

Further are attachable attenuators, the externally to the test pin can be mounted known. attenuators are used to selectively attenuate a signal when For example, a maximum level must be respected or to the input resistance of an element to the line impedance adapt and thus prevent unwanted reflections in the line. Becomes an attenuator externally to a test pin attached, it creates a further contact point between two Components, which represents another source of error / interference for the signal to be transmitted.

By poor transmission characteristics and / or bad contact at the contact point can be so only limited bandwidths due to the degradation of the signal, in particular low-frequency bandwidths for signal transmission become.

Farther requires the patch attenuator additionally Room, however, have compact test arrangements often not the necessary space for cables, other components and accessories on.

Farther elevated one to the test pin attached attenuator the mechanical load on the test pin, for example, by an additional lateral force and the center of gravity is displaced away from the pad, thereby any leverage on strengthened the contact point become. Overall, the centering accuracy is negatively affected.

outgoing from the illustrated general state of the art is the invention the task is based on a test pin according to the preamble of the main claim in cooperation with an attenuator be improved so that a compact and low-loss construction is made possible and the high-frequency properties are improved by the of crossing points caused disturbances, especially for high frequencies, minimized, and at the same time an input-side adaptation through the attenuator takes place, whereby reflections are minimized.

The Task is performed by the high-frequency probe with the characteristics of Main claim solved; advantageous developments of the invention are described in the subclaims. Additional protection in the context of the present invention is claimed for a high-frequency test arrangement with the characteristics of the independent Claim 10.

Of the High-frequency test probe with the features of the main claim it manages, with very few Get through contact points between individual elements and so compared to the State of the art to obtain a particularly advantageous transmission behavior. Furthermore, a particularly compact construction is made possible which is opposite to the State of the art, on the one hand, the mechanical load on the test pin and other components is reduced and on the other hand, the space requirement is lowered, allowing for more compact and precise test setups to let.

In the scope of the invention, all combinations of at least two of in the claims, the description and / or figures disclosed features.

In a preferred embodiment According to the invention, the attenuator extends in the direction of the inner conductor and interrupts this or leads this for a certain section further. This will be a particularly compact Construction possible, wherein an advantageous transmission characteristic is achieved by the attenuator a Part of the inner conductor forms. The transitions between the inner conductor and the attenuator preferably soldered, which ensures good electrical properties and a firm hold.

It has continued to be constructive advantageous exposed, the contact of attenuator to the outer conductor in the form of a one-piece form so close to the geometry of the flange Cavity respect can be taken. In a cylindrical test pin or cylindrical cavity an annular flange has proven to be particularly advantageous because this can be used accurately.

To have a particularly good contact with the au To ensure ßenleiter and thus to obtain a good transfer characteristics, it has proven to be a further development practical that the flange is axially supported on an inner annular shoulder of the outer conductor, and is pressed by spring means, in particular a compression spring against the annular shoulder. This results in a large, firmly ansitzende contact surface to the outer conductor. The spring means secure the fixed positioning. As a further spring means may alternatively be used in addition to the conventional compression spring also preferably electrically conductive elastomers, disc spring (packages), multi-corrugated spring washers or Faltebälge.

Prefers the spring means are designed so that they have an axial spring movement an outer conductor contact element cause. This suspension allows manufacturing tolerances at the high-frequency contact partner compensate. Are the spring means for consolidating the position of the attenuator therefor used with, allows itself a particularly compact construction.

It has proven to be advantageous to build the outer conductor in several parts, as this allows easier installation. At least uses two coaxial elements which are movable relative to each other are. One of the elements is designed as a preferably tapered contact point and serves to make contact with the high-frequency contact partner. The others preferably radially outboard Element can serve as a sleeve, whereby a modular assembly of the test pin allows. For example, first, the attenuator in the radial external Sleeve are inserted, whereupon the spring means and finally the contact point trained outer conductor element consequences.

Prefers are the elements of the outer conductor guided in the axial direction one behind the other and preferably by a flanging limited, at least in sections along the conical side surface of runs as a contact point formed element. This will be a solid cohesion of the test pin ensuring and in particular prevents the outer conductor contact point off the test pin can fall.

Especially It is advantageous if the attenuator one piece as a disk attenuator is trained. This allows a simple assembly, used in the few items become. Especially with the attenuator located inside the test pin It is advantageous if easy to use and easily removable again is, among other things about defective attenuators to exchange efficiently.

Prefers Be along the path through a section of the attenuator interrupted inner conductor axially acting spring means provided. This allows Manufacturing tolerance at the high-frequency contact partners are compensated and shocks, about when putting on or off or during the Operation, be intercepted.

in the Within the scope of the invention, it is preferred with at least one of the test probes according to the invention a plurality of these test pins, a high-frequency test arrangement in the form of a test adapter to realize which on or in a preferred plate-shaped carrier element a plurality of test pins having. The test arrangement points at least one high frequency contact partner (examinee), an evaluation unit and a transmission path between test pin and evaluation unit. this makes possible the realization of even complex test systems.

Around particularly good transmission conditions To obtain, the resistance values of the attenuator to the characteristic impedance the transmission line and / or the input impedance of the evaluation unit, wherein typical values for this for example 50 ohms or 75 ohms. This causes annoying reflections the transmission line, which occur especially in high-frequency operation, suppressed.

in the Result enabled the invention in surprising simple and advantageous way, the arrangement of test pin and attenuator To improve so that a particularly compact structure with possible few crossing points between individual elements allows becomes. Targeted signal attenuation and reflection suppression be on a low-wear, highly contact-reliable and cost-effective way.

Further Advantages, features and details of the invention will become apparent the following description of preferred embodiments and by reference the drawings.

These show in:

1 a longitudinal section through a coaxial RF test pin according to the invention;

2 an equivalent circuit diagram of the arrangement according to 1 ;

3 a frequency / attenuation diagram for representing simulated reflection attenuation values for a circuit according to 2 ;

4 a frequency / attenuation diagram for representing simulated transmission loss values for a circuit according to 2 ;

1 shows in longitudinal section view a high-frequency test pin 8th according to a preferred embodiment of the invention.

The test pin 8th is in its outer contour 9 essentially cylindrical. Furthermore, the test pin 8th an outer radial flange 13 provided for a firm axial hold of the test pin 8th provides in a test arrangement and additionally serves as anti-rotation.

At its left and right ends, the test pin has contacts for contacting both an inner conductor 14 as well as an outsider 16 on. At the contacts 10 at the left end an external contacting is provided here, by which in particular an evaluation unit 34 over a transmission path 32 can be contacted. He has contacts at the right end 12 for a high-frequency contact partner, not shown 30 on, which are formed in the form of a contact tip.

The outer conductor 16 runs coaxially to the center axis of the test pin 8th consisting essentially of an outer conductor sleeve 18 taking the majority of the outer contour 9 of the test pin 8th forms, and an outer conductor contact tip 20 composed. The contact point 20 used to pick up a signal or the ground at the high-frequency contact partner 30 , The outer conductor sleeve 18 and the outer conductor contact tip 20 are displaceable relative to each other, thereby allowing the outer conductor contact tip 20 axially to manufacturing tolerances on the high-frequency contact partner 30 can adapt.

An outer conductor spring 26 ensures a restoring force at the outer conductor contact point 20 ,

Through the outer conductor 16 becomes a cavity 21 formed in which an attenuator 22 located. The attenuator 22 is designed here as a one-piece disk attenuator. The cavity 21 is in its inner contour fit to the attenuator 22 adjusted, which contributes to a good grip. The attenuator 22 is at two contact points 25 with the inner conductor 14 connected. Furthermore, the attenuator 22 partially an annular flange 24 through which it passes the outer conductor 16 contacted. This ring flange 24 puts on a ring heel 23 of the supervisor 16 on and is by the outer conductor spring 26 axially pressed against these and thus establishes an electrical contact. Furthermore, the attenuator contacts 22 the outer conductor 16 at its outer periphery.

Along the center axis of the test pin 8th runs an inner conductor 14 , He is the leader 16 mechanically protected. At the right edge of the test pin 8th has the inner conductor 14 a contact tip 15 for contacting the radio frequency contact partner 30 on. In its axial course is the inner conductor 14 sections through areas of the attenuator 22 educated. The inner conductor 14 is through an inner conductor spring 28 to the high-frequency contact partner 30 sprung and through the spring 29 to the contacts 10 spring-loaded for an external contact.

Not shown are insulation used in the contacts 10 for an external contact and the outer conductor 16 from the inner conductor 14 disconnect electrically, thus preventing a short circuit between them.

The signal curve of the inner conductor 14 runs from a contact of the test pin 8th with the contact partner 30 on the inside of the contacts 12 over a feather area 28 to the attenuator 22 , From the attenuator 22 the signal passes over another spring range 29 to the contacts 10 for external contacting.

The signal course at the outer conductor 16 runs from the outer contact of the contacts 12 both over the outer sleeve 18 as well as via the outer conductor contact tip 20 as well as the outer conductor spring 26 , The signal of the outer conductor 16 goes from the point of contact with the attenuator on to the contacts 10 for external contacting.

The electrical equivalent circuit diagram of in 1 shown test pin 8th with attenuator 22 is in 2 shown. The electrical properties of the test pin 8th without the attenuator 22 are through the black box element 70 shown. The attenuator 22 realized between inner conductor 14 and outer conductor 16 a damping circuit in the form of a T-circuit, which here by the three resistors 72 . 74 and 75 is shown. The outer conductor 16 is represented by the mass symbol.

The test pin is at the point 38 at one with the contact partner 30 connected. Otherwise he is at the point 36 connected to the evaluation unit, which may still have a non-illustrated transmission line 32 with further electrical properties in between.

In 3 are the results of a simulation at the in 2 shown applied circuit for an expected return loss. The frequency in GHz is plotted on the x-axis of the coordinate system. On the y-axis the expected return loss in dB. line 50 shows the return loss without attenuator. line 52 shows the return loss with a 3 dB attenuator. Here is opposite line 50 determine a shift by about -6 dB. line 54 shows the return loss with a 10 dB attenuation element. Here is opposite line 50 detect a shift of about -20 dB. Even at frequencies of 4 GHz, an absolute return loss of about -40 dB can be guaranteed with a 10 dB attenuator. By suitable choice of the attenuator 22 Thus, an undesired return of the input signal can be successfully suppressed.

In 4 are the results for a simulation at the in 2 shown circuit for an expected transmission loss. The frequency in GHz is plotted on the x-axis of the coordinate system. On the y-axis the expected transmission loss in dB. line 60 shows the transmission loss without attenuator. line 52 shows the transmission loss with a 3 dB attenuator. line 64 shows the return loss with a 10 dB attenuator.

The combination of 3 and 4 shows that improved return loss can be achieved at the expense of an attenuated transmission signal. If, for example, the return loss is to be improved by -6 dB, then a 3 dB attenuator can be inserted into the test pin. In another example, it may be desirable to selectively attenuate the transmission signal by -10 dB by inserting a 10 dB attenuator. In the case of reflux, an additional attenuation of about -20 dB is obtained in this case.

The present invention is not limited to the embodiment shown, the attenuator 22 In addition to the position shown in the example, which is immediately after moving contact parts, according to the invention can also be arranged at other locations within the Prüfstifts, for example when connecting 10 for an external contact.

Farther it can be provided, the attenuator according to the invention in one Bushing instead of a test pin provided.

LIST OF REFERENCE NUMBERS

8th

test pin

9

outer contour of the test pin

10

contacts external

12

contacts examinee (High-frequency contact partner)

13

outer flange of the test pin

14

inner conductor

15

Inner conductor contact tip

16

outer conductor

18

Outer conductor sleeve

20

Outer conductor contact tip

21

cavity

22

attenuator

23

annular shoulder

24

annular flange

25

solder joints

26

feather (Outer conductor)

27

contact point between attenuator and outer conductor

28

feather (Inner conductor)

29

feather at the external contact (inner conductor)

30

Contact partner (Sample)

32

transmission path

34

evaluation

36

entrance (Point 1)

38

output (Point 2)

50

Return loss at attenuator with 0 dB

52

Return loss at attenuator with 3 dB

54

Return loss at attenuator with 10 dB

60

Transmission attenuation at Attenuator with 0 dB

62

Transmission attenuation at Attenuator with 3 dB

64

Transmission attenuation at Attenuator with 10 dB

70

Test pin Blackbox element

72

T-resistive element 1 of the attenuator

74

T-resistive element 2 of the attenuator

76

T-resistive element 3 of the attenuator

Claims (10)

High frequency test pin ( 8th ) for detachably contacting a high-frequency contact partner having an inner and an outer contact ( 30 ), in particular high-frequency contact socket or plug or a contacting point on a printed circuit board, with a coaxially formed, one-way contacts ( 12 ) for the high-frequency contact partner ( 30 ) offering arrangement of an outer conductor ( 16 ) and a resiliently guided in the axial direction inner conductor ( 14 ), which at the other end ( 10 ) are externally contacted, characterized in that in a by the outer conductor ( 16 ) formed cavity ( 21 ) an attenuator ( 22 which is provided for implementing a predetermined damping effect on a transmitted and / or reflected input signal at contact sections ( 25 . 27 ) contacts the inner and outer conductors. Device according to claim 1, characterized in that the attenuator ( 22 ) in the direction of the inner conductor ( 14 ) is formed extending, wherein preferably portions of the inner conductor ( 14 ) the attenuator ( 22 ) at contact points ( 25 ), in particular at the contact points ( 25 ) with the attenuator ( 22 ) are soldered. Apparatus according to claim 1 or 2, characterized in that a portion of the attenuator ( 22 ) as an integral flange ( 24 ), in particular annular flange, for contacting the outer conductor ( 16 ) is trained. Device according to claim 3, characterized in that the flange ( 24 ) axially on an inner annular shoulder ( 23 ) of the Leader ( 16 ), and spring devices ( 26 ), in particular a compression spring, against the annular shoulder ( 23 ) is pressed. Device according to claim 4, characterized in that the spring means ( 26 ) are formed so that they cause an axial spring movement of an outer conductor contact element. Device according to one of claims 1 to 5, characterized in that the outer conductor ( 16 ) of at least two coaxially arranged elements ( 18 . 20 ), which are preferably movable relative to each other and of which a preferably tapered contact element ( 20 ) and a second as a radially outer sleeve ( 18 ) is trained. Device according to claim 6, characterized in that the elements ( 18 . 20 ) are directed against each other by a material-deformed section, in particular a flange against each other. Device according to one of claims 1 to 7, characterized in that the attenuator ( 22 ) is realized in one piece as a disk damping element. Device according to one of claims 1 to 8, characterized in that along the of a portion of the attenuator ( 22 ) interrupted inner conductor axially acting spring means ( 28 . 29 ) are provided. High frequency test arrangement with at least one high frequency test pin ( 8th ) according to one of claims 1 to 9, at least one high-frequency contact partner ( 30 ), an evaluation unit ( 34 ) and a transmission link ( 32 ) from the high-frequency test pin ( 8th ) to the evaluation unit ( 34 ), wherein preferably the attenuator ( 12 ) to the characteristic impedance of the transmission path ( 32 ) and / or an input impedance at the evaluation unit ( 34 ) is adapted in high-frequency operation.