The invention relates to a coaxial test connector configured for easy and quick connection to a test object. It further relates to a self-aligning coaxial connector, i.e. a connector, which automatically aligns to a mating connector during the coupling operation.
For testing electronic devices test adapters are often used. These test adapters connect with devices to be tested to external test equipment. When testing RF devices like amplifiers, filters or others, these often have to be connected by RF connectors, which in most cases are coaxial connectors. These have comparatively tight mechanical tolerances and require a precise connection. When the connectors are attached manually to the device to be tested, the test adapter's connectors have flexible cables and are manually attached to the device to be tested. If an automatic connection between a device to be tested and a test adapter is desired, mechanical tolerances may cause severe problems. Basically, a test adapter may be built with close mechanical tolerances, but the devices to be tested are often manufactured in larger quantities and often have wider mechanical tolerances. This may lead to a misalignment of the connectors which may further lead to a damage of the connectors or to incorrect test results. Generally it would be preferred, if the connectors of the measuring adaptor and the mating connectors of the device to be tested are exactly aligned in all planes and directions.
U.S. Pat. No. 6,344,736 B1 discloses a self-aligning connector. The connector body is held over an outer radial flange, provided at its outer surface, between an inner radial flange provided at the inner surface of the connector housing and a washer pressed by an axial spring, so that it can align to a mating connector being inserted into the centering collar fixed to the connector body at least axially and in the transverse plane.
To provide a low passive intermodulation (PIM) connection, comparatively high contact forces are applied to normal coaxial RF connectors. In normal use, such forces are applied by the connector's locking nut which is tightened with a predetermined and comparatively high torque. In a test setup, locking the connectors is too time consuming. Simply pressing the connectors together would require a pressure device generating high pressure in axial direction of the connector. This is hardly feasible specifically in devices with a large number of connectors.
U.S. Pat. No. 4,374,606 discloses a coaxial connector with a plurality of contacts configured to radially contact an outer conductor. The contacts are held by a sleeve in axial direction. The sleeve engages slidably in an outer conductor.
U.S. Pat. No. 4,106,839 discloses a shielded multipole connector having a contact spring which connects the shields of mating connectors.
The embodiments are based on the object of providing a coaxial RF connector interface having high return loss in a broad frequency range and a low passive intermodulation which can be connected and disconnected by applying comparatively low forces. Preferably, the connection should be maintained without applying significant forces in an axial direction of the connector. Furthermore, the connector should have a long lifetime with a large number of mating cycles as are required for test equipment.
In an embodiment, a test connector is configured to connect to an auxiliary, compatible coaxial connector along the axis of the test connector, for example to be part of a device to be tested. The test connector provides at least an inner conductor and an outer conductor, most preferably, both conductors have a circular cross section and/or a cylindrical shape and may be inserted inwardly into another, auxiliary test connector (in an inward, axial direction to have the auxiliary, compatible test connector at least partially enclose the inner and outer conductors of the test connector at hand). In other words, the outer conductor has a circular shape configured to at least partially enclose the outer conductor of the compatible coaxial connector in a radial direction. The outer conductor further provides a groove configured to hold an approximately circularly shaped spring which is dimensioned to radially contact the outer conductor of the compatible coaxial connector and assert or apply an approximately radially-directed contact force to said outer conductor.
Preferably, the contact spring is a finger gasket. Preferably, the contact spring has a plurality of individual contact fingers with a preferably small gap between the individual contact fingers. The contact fingers may have additional contact elements or contact points at their outer sides to improve contacting of the compatible coaxial connector. It is preferred, that the widths of all or at least of most of the gaps between the individual contact fingers is less than the width of a finger, preferably equal or less than half and most preferably less than ⅓ of the width a finger. It is further preferred to have the widths of all or at least of most of the fingers finger be less than 1 mm and preferably less than or equal to 0.5 mm. Furthermore, the individual contact fingers preferably are arranged as part of a common base and, therefore, are held together by the common base. It is preferred to have the base be held by the test connector and the contact fingers be pressed radially against the outer conductor of the compatible, auxiliary coaxial connector. Preferably, the contact fingers extend by a bow (in a curved fashion) from the base.
Preferably, at least one of the contact fingers includes a first contact section dimensioned to contact the compatible coaxial connector in a radial direction, when such compatible connector is attached. Such contact finger(s) further comprise(s) a second contact section dimensioned to contact a sidewall of the groove formed in the outer conductor. Most preferably, the second contact section is in capacitive contact with the sidewall of the groove, although a galvanic contact may also be useful (preferably at lower frequencies, such as within the range from kHz to MHz or even lower). Most preferably, the sidewall of the groove is oriented in outward direction (opposing the inward direction), therefore facing in a direction towards the compatible connector with which the test connector at hand can be axially interconnected. As a result of establishing the contact between the second contact section and the sidewall, an area forming a current loop by the current flowing from the outer conductor of the compatible connector to the test connector is reduced, which further increases a bandwidth of the connector (or a bandwidth corresponding to a combination of connectors).
In another related embodiment, the outer conductor of the test connector may contains a spring holder being part of or forming the groove, which holds the contact spring. Preferably, the contact spring is soldered and/or welded to the spring holder. Most preferably, it is soldered and/or welded at its base to the spring holder. Solder may be applied radially outside of the base of the contact spring to the spring holder. To achieve better intermodulation characteristics (of the interconnected connector units), only one metallurgical connection (the solder connection) between the contact spring and the spring holder can be established. To provide a capacitive contact and to prevent any galvanic contact in an axial direction, an insulating disk may be placed between the bow of the contact spring and the spring holder. Such insulating disk may comprise a suitable insulating material, which may be ceramics, or a plastic material, which may be PTFE or Polyimide. Furthermore, in one embodiment it is preferred if the insulating disc has a high dielectric constant to establish a high coupling capacity between the spring and the spring holder. It may be further preferred, if the spring holder has a thread interfacing with a thread at the outer conductor of the test connector. Such configuration allows the spring holder to be screwed (preferably in an axial direction of the connector) on the outer conductor.
In an alternative embodiment, the spring holder may be pressed, soldered, or welded to the outer conductor of the test connector.
In yet another related embodiment, the spring holder may be structured to be a part of the outer conductor of the test connector providing a circular gap or groove configured to hold the contact spring. In this case, the contact spring preferably has a shape and size dimensioned such that—when the compatible coaxial connector is inserted into the test connector—the axial force between the contact spring and the outer conductor of the test connector is sufficiently large to deform the contact spring, such that it further asserts a significant force to the outer conductor of the test connector to ensure proper and operably sufficient contacting. This may be achieved by arcuately shaping the fingers.
The disclosed embodiments have the advantage in that the contact spring can easily be mounted into the test connector. It is not necessary to solder or weld the contact spring into the test connector. The contact spring can withstand a large number of mating cycles (between the two compatible connectors) without suffering from being materially fatigued or starting to initiate poor contacts.
Preferably, the base has a larger radius than that of the contact fingers, with respect to the center axis. Therefore, preferably, the base is essentially radially enclosing the contact fingers. This results in a very compact size of the overall assembly and short current paths between the outer conductors of the compatible coaxial connector and the test connector, which in turn leads to good impedance matching in a broad range of frequencies and, therefore, high return loss.
It is further preferred, if the number of contact fingers is higher than 10, preferably higher than 20 and most preferably higher than 40 to achieve a low impedance broadband contact.
It is further preferred, if the outer conductor of the test connector has at least one contact section configured to provide a mechanical contact to, and therefore a mechanical alignment with, the compatible coaxial connector. It is further preferred, if the spring holder provides at least one such a contact section. Preferably, there is at least one radial contact section configured to provide a radial alignment of the compatible coaxial connector and the test connector. It is further preferred, if there is at least one axially oriented contact section configured to establish axial alignment between the compatible coaxial connector and the test connector at hand.
In a further related embodiment, the test connector provides a connector guide configured to guide the compatible coaxial connector towards the test connector during the process of insertion of the compatible coaxial connector into the test connector. It is further preferred, if the connector guide has a cone-shaped entrance side to simplifying such insertion of alignment with the compatible coaxial connector.
Independently of the previously described embodiments, the center conductor may either be of a male type or a female type.
In one embodiment, the contact spring is made of at least one of the following materials: copper-beryllium, brass, steel.
Alternatively or in addition, the compatible coaxial connector is a 7/16 DIN connector, as specified in the German standard DIN 47223.
In the following portion of the disclosure, the invention will be described without limitation of the general inventive concept, with the use of examples of embodiments and with reference to the following drawings.
Various modifications and alternative forms can be introduced to the examples of embodiments discussed below without limiting the scope of the invention to the particular discussed example. To the contrary, the scope of the intention is intended to cover all modifications, equivalents and alternatives falling within the spirit and scope defined by the appended claims.
In
In
In
In an alternate embodiment, the spring holder 51 may be one part with the outer conductor base 31. In this case, it forms a groove 45 configured to hold the contact spring 55. It is further preferred, if the outer conductor 50 has at least one mechanical contacting surface. Most preferably, there is at least one axially oriented mechanical contact section 53. There may be a further mechanical contact section 54 which is oriented radially.
In
The compatible coaxial connector's outer conductor 120 preferably has a hollow end section 121 which is contacted in a radial direction by the contact spring 55 in a contact area 122.
Mechanical alignment of the compatible coaxial connector 100 to the test connector 30 is done by mechanical contact sections at the outer conductor of the test connector and of the compatible coaxial connector 100. For radial alignment, an outer section 123 of the outer conductor of the compatible coaxial connector 100 may contact a radial mechanical contact section 54 of the outer conductor of the test connector. Axial alignment may be done by an axial contact section 133 of the compatible coaxial connector 100 contacting the axially mechanical contact section 53 of the outer conductor of the test connector. Preferably, the axial contact section 133 is part of the housing 130. There may be a chamfer 134 at the edge of the axial contact section 133. Such independent radial and axial alignments ensure proper and reproducible alignment of the connectors. To simplify mating of the connectors, the outer side of the outer conductor 50 may have a chamfer 52. To provide an early alignment during mating of the connectors, a connector guide 60 at the test connector 30 preferably has a cone 61 with an interface section 65 to interface and/or guide the housing 130 and/or an outer thread 131 at the housing.
In
In
In
In
It will be appreciated to those skilled in the art having the benefit of this disclosure that this invention is believed to provide RF coaxial test connectors. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
Number | Date | Country | Kind |
---|---|---|---|
15152199 | Jan 2015 | EP | regional |
15195915 | Nov 2015 | EP | regional |
This application is a continuation of the pending International Application No. PCT/EP2016/050451 filed on Jan. 12, 2016 and now published as WO 2016/116326, which designates the United States and claims priority from the European Application No. 15152199.4, which was filed on Jan. 22, 2015 and the European Application No. 15195915.2, which was filed on Nov. 23, 2015. The disclosure of each of the above-mentioned applications is incorporated by reference herein.
Number | Name | Date | Kind |
---|---|---|---|
2762025 | Melcher | Sep 1956 | A |
3871735 | Herrmann, Jr. | Mar 1975 | A |
4106839 | Cooper | Aug 1978 | A |
4355857 | Hayward | Oct 1982 | A |
4374606 | Lathrop | Feb 1983 | A |
4812137 | Wilson et al. | Mar 1989 | A |
5195904 | Cyvoct | Mar 1993 | A |
6344736 | Kerrigan et al. | Feb 2002 | B1 |
6379183 | Ayres | Apr 2002 | B1 |
7794274 | Phillips, Jr. | Sep 2010 | B2 |
9124010 | Eriksen | Sep 2015 | B2 |
20130065415 | Van Swearingen et al. | Mar 2013 | A1 |
20130130543 | Holland et al. | May 2013 | A1 |
20150229070 | Van Swearingen | Aug 2015 | A1 |
20150270635 | Wollitzer | Sep 2015 | A1 |
Number | Date | Country | |
---|---|---|---|
20170324197 A1 | Nov 2017 | US |
Number | Date | Country | |
---|---|---|---|
Parent | PCT/EP2016/050451 | Jan 2016 | US |
Child | 15655064 | US |