ANTENNA CONNECTOR

Abstract: The invention relates to a coaxial RF antenna connector for electronic devices having a thin frame construction. The coaxial RF antenna socket, which supports a swivelling antenna, are snap mounted on a frame and consists of a plastic body with integrated contacts that interconnect the antenna socket and pads on a PCB. A solder-free interconnection is established through the three contacts.

Description: ANTENNA CONNECTOR TECHNICAL FIELD OF THE INVENTION. The invention relates to antenna connectors for thin support construction in electronic devices as well as to an electronic device including such an antenna connector. BACKGROUND OF THE INVENTION. This invention is a result of a cooperation between IMS Connector Systems of Lόffingen, Germany, and the applicant. A card phone is a device for transmitting and receiving digital information via a wireless radio link and it is often used in combination with a portable personal computer (PC) like a lap top. The card phone could entirely or partly be formed like a card for enabling insertion into the PC having a slot containing the corresponding contacts as the phone card is provided with. The card phone comprises a frame of metal, a casing, electric contacts, an antenna and a radio part inside the casing having different circuitry like modulators, demodulators, transmitters, receivers and power amplifiers mounted on a Printed Circuit Board (PCB). The antenna is electrically connected to the radio part. The PC card has an antenna contact that is holding the antenna, conducts an antenna signal from the antenna to the circuits on the PCB and connects the antenna to the ground terminal on the PCB. Said contact is applied to the PC card in different ways. The antenna contact can be surface mounted or manually soldered on the PCB. The ground signal is conducted via the casing and the antenna signal via a contact pin. Most suppliers of Radio Frequency (RF) contacts have such contacts in their assortment. However, the load distribution area is limited, which results in poor capability to withstand loads and bending moments transferred from the antenna . Instead of attaching the antenna contact to the PCB an elastic socket is fastened to the metallic frame. The socket is connected to the ground potential via the frame. The antenna signal is coupled to a contact pin and conducted to the circuits on the PCB. Following documents gives some good examples of prior art solutions. The document US, , 5 907 817 (Dl) reveals an antenna connector for a radiotelephone which includes three contacts - two ground contacts (131 and 133) positioned on opposing sides of one "live centre" contact 132. In document US, A, 5 293 177, an antenna connector is shown which comprises a first housing 20 for housing an end of a coaxial cable and a second housing 30 for housing the first housing. The housings are interconnected with a pair of feeding plates 61, 61' on the PCB. In document US, A, 5 929 815, an antenna connector is disclosed which is secured to a frame by threaded fastener 77 and secured to the PCB by a conductively securing the one or more ground pins and the pin portion to the PCB. The PCB is soldered, brazed or otherwise conductively bonded to said ground pins 83. SHORT DESCRIPTION OF THE INVENTION There is a considerable risk that the antenna will be exposed to a force resulting in a bending momentum. The antenna connector may be destroyed and the thin electronic device totally useless even at a very small bending moment amplitude . The risk for collapse will increase as the thin electronic devices, like PC cards, decrease in size. The thickness of the card frame will be 5 mm or less resulting in a small allowed thickness of material to support the antenna connectors. As the possible space for an antenna connector decrease, the size of the antenna connector has to decrease. The object of this invention is to design a new antenna fixture that overcomes the previous mentioned drawbacks of prior art antenna contacts. The invention is an antenna connector for snap mounting the antenna connector in a frame construction. In a preferred embodiment it consists of a plastic body with integrated contacts that interconnect the antenna socket and pads on a PCB. A solder-free interconnection is established through the three contacts. The invention is also directed towards an electronic device including such an antenna connector. In more detail the invention is an antenna connector for electronic devices comprising a thin frame support construction having an antenna socket recess and said antenna connector comprises a socket housing having at least one snap locking device for mounting said connector into the antenna socket recess. The invention has a lot of advantages over prior art. It has a robust design that manages heavy loads and it's a compact design of the plastic housing. It saves space on a PCB because it is mounted aside said PCB. The invention is solder-free and no glue is needed for attaching the housing or the contacts. It is easy to produce and apply at different wall thickness any space. If a swivelling antenna is used, the connector manages a lot more rotation cycles than earlier known PCB mounted connectors. BRIEF DESCRIPTIONS OF THE DRAWINGS Figure 1 is a top view of a frame support construction. Figure 2 is an antenna side view of the same frame support construction as in figure 1. Figure 3 shows a front view of an embodiment of an antenna connector according to the invention. Figure 4 shows a top view of an embodiment of an antenna connector according to the invention. Figure 5 shows a side view of an embodiment of an antenna connector according to the invention. Figure 6 is a top view of a schematic electronic device. Figure 7 is a front side view of the same device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a frame construction 10 is viewed in figure 1 and figure 2. Figure 1 is a top view and figure 2 is an antenna side view. The frame 12 is thin and rectangular with four walls, two short ends 22a, 22b and two long sides 24a, 24b, but it could have any shape. The frame construction 10 is designed with an antenna connector recess 14 for insertion of an antenna connector. The front side 22a, also called the antenna side, has an antenna opening 16 leading to the antenna connector recess 14. The other short end, insertion side 22b, has a contact recess 18. The inner side 28 of the frame walls has a PCB (Printed Circuit Board) ledge 20. A PCB board can rest on and be fastened to said ledge 20. Figure 3 shows a front view, figure 4 a top view and figure 5 shows a side view of an embodiment of an antenna connector 30 according to the invention. Integrated, hidden details are drawn in dashed lines. The antenna connector comprises a socket housing 32 and different electrical contact parts such as the antenna socket 34. The socket housing 32 is moulded in plastic material. The socket housing 32 has four sides having a generally rectangular shape as well as top and bottom surfaces. In this embodiment of the invention the housing 32 has one top surface or side 46a, one bottom surface or side 46b, two side walls 48a, 48b, one connector front side 50a and one connector back side 50b. The side walls and connector front and back sides are the same four sides mentioned above The walls of the antenna recess 14 have the general shape of the antenna connector 30 or in other words the recess 14 is preferably generally complementary in shape to the shape of the antenna connector 30 such that the antenna connector 30 is easily insertable in and removable from the recess 14. That is each wall of the antenna recess correspond to a side of the socket housing. The socket housing 32 has at least one snap locking device 36 and at least one stop flange 38 protruding from the housing 32 for securing the housing 32 in the frame construction 10. Generally the side walls 48a, 48b are provided with two stop flanges 38 each. One of these stop flanges is provided in or within proximity of the top corner where the connector back side 50b and the top side 46a meet and the other in or within proximity of the top corner where the connector front side 50a and the top side 46a meet. A snap locking device 36 comprises a flexible spring arm 40 having a arm flange 42 and an arm recess 44. The arm flange 42 and spring arm 40 have to be pressed into the arm recess 44 behind the spring arm 42 during the insertion of the antenna connector 30 into the antenna connector recess 14 of the frame 12. The antenna connector 30 is fully inserted when the flexible spring arm 40 springs or snaps out because the arm flange 42 and the side stop flanges 38 have reached their locking positions. In this embodiment the locking positions are decided by the opposite edges, in the antenna connector insertion direction, of the inner wall of the antenna recess 14. The distance between said edges could be equal to or less than the thickness of the frame. It is therefore possible to modify the distance D between the flanges 38,42. In above described embodiment, two snap locking device are provided on two opposing sides 48a and 48b of the socket housing. Each arm flange 42 is provided about half way between the connector front 50a and back 50b sides in proximity of the bottom surface 46b. When the socket housing has been inserted from the top into the recess which preferably has a rectangular shape, the stop flanges hit the upper rim or edge of the recess walls and the arm flanges flex around the lower rim or edge of the recess walls so that the arm flanges and stop flanges keep the socket housing tightly fit in the recess. Alternatively the walls of the antenna socket recess might have their own recesses for receiving the spring arms of the snap locking devices in order to fasten the socket housing. The antenna socket housing 32 contains a hollow area which is reached through an opening on the connector first side 50a. In this hollow area a device 34 for mechanically securing the antenna in the housing and for providing good electrical connection is provided. Said device is characterized as an antenna socket 34. The connector 30 has at least two contact members - at least one signal contact member 52 for the antenna signal and at least one grounding contact member 54 for the grounding of the antenna. In this embodiment a conducting sleeve 34 is used as a antenna socket 34 having an inner wall with radius r and an outer wall with radius R. The sleeve has a generally cylindrical shape. It can however have different shapes depending on the shape of the antenna contact to be received. The antenna socket 34 has one front end 56 for receiving the antenna and a second rear end 58 on the opposite side. At least a part 60 of the antenna socket's outer area is in direct contact with the socket housing 32 and this fixing part 60 is holding and securing said socket 34. The other part of the outer socket area is a free area 62 and there is a distance d between the socket 34 and the socket housing 32. Two electrical contact members 52,54 are connected to the antenna socket 34 and protrude backwards in the same direction as the antenna is inserted, that is the insertion direction. The direction goes from the front end 56 to the second rear end 58. A signal contact 52 is located in the centre at the second end of the socket 34. The antenna socket 34 is connected to the ground via the grounding contacts 54a, 54b. In this embodiment the contacts are in a solder-free connection to ground potential pads on a Printed Circuit Board. The grounding contacts 54 and the signal contact 52 are flexible and when mounted to the PCB the ends of the contacts will be displaced in a direction perpendicular to the PCB. The contact arms 64a-c will be bent and the ends 66a-c will be pressed against the pads 86 (see figure 6) . In one embodiment the socket is an electrically conducting sleeve that is flexible and has the free area 62 divided by parallel slots 58 from the front edge 56. The sleeve can expand said distance d when an antenna contact is forced into the sleeve 34. An antenna locking flange male part 70, designed as a narrowing or tapering, is decreasing the radius of the inside radius r of the sleeve. The narrowing 70 is annular and located on a suitable distance from the front end 56. This flange male part is therefore a ring shaped member on the interior wall of the sleeve. The ring shaped member 70 is located in parallel with the front end 56 and the second rear end 58 and between these two ends. Figure 5 is a side view of the antenna 72 and the antenna connector 30. The antenna has an antenna contact 74 comprising a central contact member 76 and a coaxial contact member 78. The antenna 72 has a corresponding locking flange female part 80 or a recess on a suitable location on the antenna contact 74. In this recess the male flange part will fit upon insertion of the antenna contact in the antenna connector. The male part 70 and female part 80 will be joined, locking and holding the antenna 72 in place when the antenna is fully inserted. The locking flange 70 could be designed in different ways depending on the kind of antenna socket. The sleeve 34 allows the antenna to rotate in the socket. This antenna type is often called swivelling antenna. When the antenna is inserted into the socket, as seen in figures F and G, the central contact member 76 will be connected to the signal contact member 52. Figure 6 is a top view of a schematic electronic device 90 having a thin frame construction according to an embodiment of the present invention, showing an antenna 72 attached to it but with a top lid taken away. Figure 7 is a front side view of the same device 90 showing some hidden details like the PCB and the electronic components with dashed lines. Said electronic device will here after be termed as a card. A PC card is an example of such a design. The disclosed card is rectangular with one insertion side and an opposing front side (compare figure 1) . An antenna socket 34 is easily accessible on the front side. When the antenna 72 is mounted onto the antenna socket 34 the card is ready for transmitting a radio signal from an internal source. Similarly, the card is adapted for receiving a radio signal from an external radio source. A connector member 82 is fixed mounted on the insertion side 22b for connecting the circuits and components 88 mounted on a PCB 84 inside the card with another electronic device like a PC. The signal contact member 52 and the grounding contact members 54 protruding from the antenna connector 30 are in solder-free contact with the contact pads 86 on the PCB 84. The swivelling antenna may be rotated freely around its contact axis. Any force acting on the antenna 72 will be transferred to the frame support construction. The PCB will not be exposed to the force and there will be no risk for any damage of the PCB as a result of such a force. The invention could be used in different electronic devices, like mobile radio communication terminals, having a supporting frame construction and an antenna.

Claims: CLAIMS 1. Antenna connector (30) for electronic devices comprising a thin frame support construction (12), characterised in that said antenna connector (30) comprises a socket housing (32) having at least one snap locking device (36) for mounting said connector (30) into an antenna socket recess (14) of said thin frame support construction (12). 2. Antenna connector (30) according to claim 1, characterised in that said snap locking device (36) comprises a flexible spring arm (40), an arm flange (42) and arm recess (44). 3. Antenna connector (30) according to any previous claim, characterised in that said antenna connector (30) also comprises an antenna socket (34) and a signal contact member (52) integrated in the housing (32) . 4. Antenna connector (30) according to claim 3, characterised in that said antenna socket (34) is an electrically conducting sleeve (34) shaped to receive an antenna contact (74) . 5. Antenna connector according to claim 4, characterised in that said antenna socket includes a locking male flange part (70) for securing the antenna in the antenna connector. 6. Antenna connector (30) according to claim 4 or 5, characterised in that a swivelling antenna (72) is detachably attached to said sleeve (34). 7. Antenna connector (30) according to any of claims 4 - 6, characterised in that at least a part (60) of the outer area of the antenna socket is in direct contact with the socket housing (32) and this fixing part (60) is holding and securing said socket (34) to said housing (32 ) . 8. Antenna connector (30) according to any of claims 3 - 7, characterised in that the signal contact member (52) is only pressed onto a pad (86) of a PCB (84), when the connector is mounted in the- antenna socket recess . 9. Antenna connector according to any previous claim, characterised in that the socket housing has a boxlike shape with four sides (48a, 48b, 50a, 50b) and a top (46a) and bottom surface (46b). 10. Antenna connector according to claim 9, characterised in that a first snap locking device (36) is provided on a first (48a) of the four sides. 11. Antenna connector according to claim 10, characterised in that a second snap locking device is provided on a second (48b) of the four sides, opposite the first side. 12. Antenna connector according to claim 9, characterised in that an opening for an antenna socket is provided on one (50a) of the four sides of the connector housing. 13. Electronic device (90) comprising a thin frame support construction (12), characterised in that it has an antenna socket recess (14) and an antenna connector (30) comprising a socket housing (32) having at least one snap locking device (36) , wherein the connector (30) is fastened in the antenna socket recess (14) by the snap locking device.

Inventors: KRONESTEDT VIKTOR, ROMBACH VOLKER, KRONESTEDT, VIKTOR, ROMBACH, VOLKER
Applicants: ERICSSON TELEFON AB L M, KRONESTEDT VIKTOR, ROMBACH VOLKER, KRONESTEDT, VIKTOR, ROMBACH, VOLKER, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 2001
Main classification: H01Q1
IPC codes: H01Q1