EP1054474A1 - Coaxial 50 ohms connector for radio frequences - Google Patents

Abstract

The 50 ohm coaxial connector has a female and male (5) section. The male section is connected to a coaxial cable (C2), and has a connector unit (55) at the other end. The connector nut has a central pin (61). The female section has an outer channel connection moving against the annular surface.

Description

The present invention relates to a 50 Ω connector for connection of coaxial cables, more especially intended for applications of radio transmission.

This connector was developed in view of a need emerging in the field of wireless telephony.

This technology is currently in full swing, that subscribers are connected by radio to a base station integrated into the network (DECT system). In practice, at the end of the installation of the subscriber, there is an antenna for communication with the base station (called RFP), and a box subscriber (called CTA) physically connected to the antenna.

Until today, the distance of the subscriber to the base station remained within limits, about five kilometers maximum, which not require high performance of said subscribed radio transmission means, and in particular said physical antenna-box connection at its adaptation. And priority has therefore been given to the economic aspect to achieve this connection including coaxial cable, connector for external connection to the 50 Ω impedance antenna and a connector for internal connection to the housing also impedance 50 Ω. So in addition to the connector high quality for connection to the antenna which it cannot be saved because of its outdoor location, are conventionally used of the 75 Ω cable of a current model and a connector 75 Ω for connection to the CTA box, which is a inexpensive model known as type connector F according to the international IEC standard. This cable coaxial, despite its low cost, has the advantage of being relatively efficient in the frequency range useful radio, since its linear loss is is around 0.3 dB / m. However, overall the adaptation of the link remains poor: around 19 dB average ROS (ratio of transmitted power to the reflected power).

In order to improve the adaptation of the link, a solution is to use components all having a impedance of 50 Ω, this solution being made all the more interesting that has been developed and put in trade by the company Bieffe S.R.L., under the reference CO150af, a new 50 Ω coaxial cable relatively inexpensive and performance noticeably equivalent to those of the aforementioned 75 Ω cable (loss at about 0.3 dB) for the same diameter of 7 mm.

A link was missing to implement this solution satisfactorily, being a 50 Ω connector suitable for connection to CTA housing.

It is in order to best meet this need that has was made the invention, with the dual purpose of a low cost and good connection quality.

For this purpose, it was opted for a design of connector inspired by that of the 75 Ω connector of type F above, because of the interest of the latter in terms of cost, but perfected with a view to significantly superior performance.

The invention therefore consists of a coaxial connector 50 Ω for radio frequencies, characterized in that it includes a socket-type female part intended for be mounted at the outlet of equipment such as a housing electronic, at the end of a coaxial cable of said equipment, and a male part for connection to a outdoor coaxial cable, female and male parts comprising tubular metallic bodies locking at the end of each other by means of a nut and ensuring the electrical connection of peripheral conductors of said coaxial cables, while the electrical connection between the central conductors of these is provided by a male part pin cooperating with pliers tubular of the female part, the end of connection of the female part being an end edge an external chamfer, applied during locking against an annular surface at the end of connection of the male part.

• le corps métallique de celle-ci présente un alésage intérieur dans lequel sont montés de l'arrière vers l'avant, un culot avec une queue de raccordement saillant vers l'arrière, et un bloc en diélectrique retenant la pince de connexion axiale ;
• le bord de l'extrémité de connexion présente en bout une lèvre périphérique sertie sur ledit bloc diélectrique retenant la pince de connexion axiale ; ou en variante, l'extrémité de connexion présente un retour intérieur définissant en bout dudit chanfrein une surface de portée annulaire transversale.

According to other preferential characteristics relating to the female part:

• the metal body thereof has an internal bore in which are mounted from rear to front, a base with a connecting tail projecting towards the rear, and a dielectric block retaining the axial connection clamp;
• the edge of the connection end has at the end a peripheral lip crimped on said dielectric block retaining the axial connection clamp; or alternatively, the connection end has an internal return defining at the end of said chamfer a surface of transverse annular bearing.

• son corps métallique forme queue de raccordement dans sa partie arrière, la fixation du câble sur ladite partie arrière étant assurée par une virole sertie, laquelle avantageusement fait partie intégrante dudit corps et peut présenter une ou plusieurs ouvertures à fonction de fenêtre de visualisation permettant de s'assurer du montage correct du câble ;
• son corps métallique porte l'écrou de verrouillage du connecteur, lequel écrou est pourvu intérieurement d'un joint destiné à assurer l'étanchéité entre la surface en chanfrein à l'extrémité de raccordement de la partie femelle et la surface annulaire transversale en l'extrémité de raccordement de la partie mâle ;
• dans une variante de réalisation, il est pourvu en sa partie arrière d'un moyen d'étanchéité sous la forme d'un presse-étoupe.

According to other preferential characteristics relating to the male part:

• its metal body forms a connection tail in its rear part, the cable being fixed to said rear part being provided by a crimped ferrule, which advantageously forms an integral part of said body and can have one or more openings with a viewing window function making it possible to s '' ensure correct cable mounting;
• its metal body carries the connector locking nut, which nut is provided internally with a seal intended to ensure the seal between the chamfered surface at the connection end of the female part and the annular transverse surface at the connection end of the male part;
• in an alternative embodiment, it is provided in its rear part with a sealing means in the form of a cable gland.

les Figs. 1a et 1b sont des vues schématiques en coupe axiale, respectivement de la partie femelle et de la partie mâle d'un connecteur selon l'invention ;

la Fig. 2 est une vue schématique partielle en coupe axiale représentant une variante de la partie mâle de la Fig. 1a ;

la Fig. 3 est une vue schématique partielle en coupe axiale représentant une autre forme de réalisation des extrémités de raccordement des parties mâle et femelle ; et

la Fig. 4 est une vue schématique en coupe axiale d'une autre variante de la partie mâle.

The characteristics and advantages of the invention mentioned above, as well as others, will appear more clearly on reading the following description, made in relation to the accompanying drawings, in which:

Figs. 1a and 1b are schematic views in axial section, respectively of the female part and the male part of a connector according to the invention;

Fig. 2 is a partial schematic view in axial section showing a variant of the male part of FIG. 1a;

Fig. 3 is a partial schematic view in axial section showing another embodiment of the connection ends of the male and female parts; and

Fig. 4 is a schematic view in axial section of another variant of the male part.

Throughout the drawings, the same references have been used to denote everywhere the same elements.

First considering Figs. 1a and 1b, they as a whole represent a 50 Ω connector according to the invention, designed to connect a coaxial cable C2 outdoor (50 Ω cable as above reference CO150af from Bieffe S.R.L.) to that C1 of equipment, for example in a telephone installation, a CTA subscriber unit within the link between it and the antenna.

The socket-type female part 1 is designed for be mounted across a wall. It involves therefore a metallic tubular body 10 having in its rear end 11 a rear support flange 13 and, in front of it and up to its front end of connection 12, an external thread intended for the screwing in a mounting nut 14 and a connection lock 55 being part in this example of the male part 5.

The front end 12 of the body 10 has a outer chamfer 12a, and ends with a lip 12b surrounding the orifice of the internal bore 15 of the body 10. The bore 15 has a first at the bottom shoulder 16, then a second shoulder 17 around a rear outlet port 18. The volume of the bore 15 is fully occupied by a metal rear cap 20, and in front of it, a dielectric block 23.

The base 20 is housed intimately between the shoulder 16 on which it rests and the shoulder 17. Its part rear forms a connection tail 21 passing through the orifice 18 and projecting axially at the rear of the body 10. The base 20, with its connection tail 21, has an axial passage channel 22, with a diameter of the internal dielectric of the coaxial cable C1 to connect.

The dielectric block 23 at the front of the base 20 in the bore 15 is in abutment against the shoulder 16. It is blocked by crimping the lip 12b on its front end. It has a central bore in which a contact element 25 is inserted. is a clamp whose front part is of the type tubular, having a plurality of elongated jaws intended to ensure perfect quality of contact with the complementary element of the male part 5.

For the connection of cable C1, the dielectric inside of it crosses channel 22 of base 20 up to abut against the rear end of the contact clamp 25 which has been crimped onto the end of the inner conductor, the connection tail 21 being fitted in the peripheral conductor and the sheath external fixed by means of a crimp ring 26.

The male part 5 comprises a tubular body 50 having at its front end of connection 51 an external collar 52 and an internal return 53 defining an axial orifice 54 bordered on the outside by an annular transverse surface 51a. The flange 52 serves as a stop for the base of the aforementioned locking nut 55 which is engaged free rotating on the body 50. Externally, the part rear of body 1 is shaped, with projections peripherals, so as to constitute a tail of connection 56 for the peripheral conductor and the external sheath of a C2 cable to be connected. The tail of connection 56 is limited towards the front by a peripheral shoulder 57.

Internally, from its rear end 58 until the return 53, the body 50 has a bore 59 diameter corresponding to that of the dielectric inside of the C2 cable to be connected. Bore 59 is empty in its major part, namely that it does not contain in the background, pressed on the return before 53, that a small dielectric block 60 intended to carry the element of axial contact, here being a pin 61 whose front part 61a projecting externally is shaped for maximum quality contact in the clamp 25 of the female part 1. The block 60 generally has the form of a thick ring wedged at the bottom of bore 59 and defining an axial passage channel for the spindle 61.

Pin 61 has a tubular rear part 61b of larger section than that of the front part 61a, and separated from the latter by a shoulder 61c. The pin 61 is engaged by its front part 61a in the block 60, the rear wall of which constitutes a support for shoulder 61c.

For the connection of cable C2, the conductor inside of it is intimately received in the rear part 61b of pin 61, until the inner cable dielectric abuts against the rear end of the spindle, the rear part of connection 56 of the body 1 being fitted in the peripheral conductor and the outer sheath of cable C2 ultimately blocked by a crimp ferrule 62.

As can be seen in the drawing, the end rear of spindle 61 and shoulder 57 limiting forward the connection part 56 of the body 50 are advantageously substantially in the same plane transverse, in order to allow and facilitate the C2 cable connection with the necessary precision to obtain the expected performance. The review of the Fig. 1b indeed shows that despite the simplicity of structure and the small number of parts of the part male 5, the assembly cooperates so that the connection of the cable can only be carried out optimally in compliance with better positioning conditions relative between the various elements.

On the other hand, when the male part 5 and the female part 1 are met, the connection quality is excellent for both internal conductors of cables through the pin clamp assembly only for their peripheral conductors through the base 20, the body 10 of the female part and the body 50 of the male part, with increased contact quality between connection ends 12 and 51 due to the chamfer 12a on the end of the female part.

Fig. 2 illustrates an improvement made to the male part 5 of FIG. 1b, this improvement consisting of that the ferrule 62 is provided here in as an integral part of the body 50, defining so with the rear part forming tail connection 56 a deep annular groove of receiving the peripheral conductor and the sheath cable C2. As shown, the wall of the ferrule 62 advantageously presents in its part before, that is to say at the bottom of said groove, one or more small openings 62a to function viewing window to check the assembly C2 cable correct when connected.

In Fig. 3, the front end 12 of the part female always has an external chamfer 12a, but which is extended here by a right interior return 12c instead of the lips 12b in the example of the Fig. 1b. The parts inside the body 50 are then put in place from its rear end, a crimping lip being closed on the edge rear of the base 20 and blocking the assembly.

With regard to the male part 5, FIG. 3 also represents its lock nut 55 with a peripheral groove 55a intended to receive a seal 65 to establish the seal between on the one hand the chamfered surface 12a of the female part 1 and, on the other hand, the flat annular surface of the end 51 of the male part 5.

In the exemplary embodiment of FIG. 4, the male part 5 'further comprises means sealing at its rear end, in the form of cable gland. Instead of forming a connection tail, the rear part 56 ′ of the body 50 ′ is threaded for receive the gland nut 66 '.

The front part of the body 50 ', and the pin 61', are essentially the same as before described and therefore do not need to be described again. In on the other hand, in its rear part, the internal bore 59 'has a first shoulder 67' for wedging of a dielectric annular block 69 'retaining the rear end of the spindle 61 ', and a second shoulder 68 'for wedging, behind block 69', a connection tail 70 'separated from the body 50', but intimately involved in it to ensure good electrical continuity between them. As in the previous case, a free space is provided in the body 50 'around the rear part of the spindle 61', between the front block 60 'and the block 69'.

The front end of the connection tail 70 ' engaged in the body 50 'forms a collar limiting the connection part proper, and against which the sealing ring 71 'of the cable gland. For the connection of cable C2, the dielectric inside the latter, engaged in the connection tail 70 ', comes to bear against the rear wall of block 69 '. As in the previous case, the arrangement of the male part 5 ′ is such that it is very easy to mount the cable C2 at best.

In the aforementioned application of the connection of a antenna to a CTA subscriber box, tests have demonstrated a very marked improvement by the use of the 50 Ω connector according to the invention in association with the aforementioned cable from the company Bieffe S.R.L. to make a connection entirely in 50 Ω, the gain in adaptation (average ROS) compared to connections currently made with materials in the same price range can be around 5 dB, or more. On the other hand, and comparatively, the 50 Ω connector according to the invention is almost the same, from a performance point of view, of a connector 50 Ω existing type N (international IEC standard) while its cost will be very much lower, at know about four times less.

Claims (9)

50 Ω coaxial connector for radio frequencies, characterized in that it comprises a female part (1) base type intended to be mounted at the outlet of a equipment such as an electronic box, at the end of a coaxial cable (C1) of said equipment, and part male (5) for connection to an external coaxial cable (C2), the female (1) and male (5) parts comprising tubular metal bodies (10, 50) are locking at the end of each other by means of a nut (55) and ensuring the electrical connection of peripheral conductors of said coaxial cables (C1, C2), while the electrical connection between the central conductors of these is provided by a pin (61) of the male part (5) cooperating with a tubular clamp (25) of the female part (1), the connection end (12) of the female part (1) having an edge at the end of an external chamfer (12a), applied when locking against a surface ring (51) at the connection end of the male part (5). Connector according to claim 1, characterized in that the metal body (10) of the female part (1) has an internal bore (15) in which are mounted from back to front, a metal base (20) with a connection tail (21) projecting towards the rear, and a block in dielectric (23) retaining the connection clamp axial (25). Connector according to claim 2, characterized in that the edge of the end of connection (12) of the female part (1) present at tip a peripheral lip (12b) crimped on said block dielectric (23) retaining the axial connection clamp (25). Connector according to claim 2, characterized in that the connection end (12) of the female part (1) has an internal return (12c) defining at the end of said chamfer (12a) a transverse annular bearing surface. Connector according to one of claims 1 to 4, characterized in that the metal body (50) of the male part (5) forms a connection tail in its rear part (56), the cable fixing (C2) on said rear part (56) being provided by a ferrule set (62) Connector according to claim 5, characterized in that said ferrule (62) is part integral with the metallic body (50). Connector according to claim 6, characterized in that said ferrule (62) has a or several openings (62a) with window function visualization to ensure mounting correct cable (C2). Connector according to one of claims 1 to 7, characterized in that the metal body (50) of the male part (5) carries said locking nut (55), which nut (55) is internally provided with a seal (65) intended to seal between the chamfered surface (12a) at the end of connection (12) of the female part (1) and the transverse annular surface (51) at the end of connection of the male part (5). Connector according to one of claims 1 to 4 and 8, characterized in that the male part (5 ') is provided in its rear part with a sealing means in the form of a cable gland (66 ', 71').

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