The present invention relates to an electrical connector having an electrically insulating contact carrier and at least one electrically conductive contact element which is provided with an impedance equalisation element. In particular, the present invention relates to an electrical connector which has defined impedance properties both with and without shielding.
Electrical connectors are known for connecting an extremely wide variety of electrical components and structures to each other, such as printed circuit boards, coaxial cables, separate circuit components, flexible circuits or the like. Generally, such connectors can produce signal and/or power supply lines between identical or similar components such as, for example, between two boards, but also between components which are not the same, such as, for example, a cable and a printed circuit board. Such plug type connectors are produced in a variety of forms and sizes, depending on the corresponding application. The form, size and spacing between the contacts of such a connector also vary significantly. Together with the form, size and spacing of the individual contacts, the impedance thereof also changes.
Since signal lines generally do not transmit any direct current, but instead only pulsed current or alternating current, so that no pulse reflections occur on the signal lines, it must be ensured that a uniform, that is to say, constant, impedance is provided. This is referred to as the so-called nominal impedance. Accordingly, when connecting lines, in particular in connection with a high-speed data transmission on associated plug type connectors, it must also be ensured that the constant impedance is maintained.
Various approaches are therefore known for adjusting a desired nominal impedance within an electrical connector using one or more contact elements. Thus, it is proposed, for example, in DE 10 2009 019 626 B3, in order to adjust the impedance of the connector, to arrange an electrically conductive impedance correction pin which is received in a bore. The bore is arranged symmetrically with respect to a plurality of contact elements.
However, it may be shown that the impedance which has been adjusted in this manner is clearly dependent on whether the plug type connector is additionally still surrounded by a shielding or not. For various applications, such as, for example, an Ethernet connection in a motor vehicle, it is highly dependent on the installation conditions whether or not a shielding against electromagnetic interspersions is necessary. In principle, for reasons of cost, the unshielded plug connector variant is always preferred and the shielding is fitted only as an alternative solution in special cases.
There is therefore a requirement for an electrical connector with a defined impedance whose impedance value can be influenced only in an insignificant manner by the presence or the absence of an electromagnetic shielding.
From U.S. Pat. No. 6,749,444 B2 there is known an electrical connector having a replaceable impedance tuner. This adjustment element is produced from a dielectric and further has impedance-adjusting metal plates which are arranged parallel with the contacts. These plates are received in the tuner and can be removed from it. The dielectric tuner can also be removed as a whole from the plug connector housing and replaced with a different tuner if another impedance value is desired. In contrast to the present invention, however, the impedance tuner according to U.S. Pat. No. 6,749,444 B2 is secured to the connector by means of a metal casing which surrounds the connector. That is to say, the impedance which is adjusted is always based on an arrangement having a metal shielding.
Although the known plug type connector is therefore extremely flexible, with regard to the adjustment of the impedance, it is comparatively expensive to produce and is necessarily provided with a metal shell which, in addition to the shielding, also has the purpose of fixing the impedance tuner in a replaceable manner.