CN1007767B - strip antenna device - Google Patents

Abstract

A strip antenna in which the ferrite core is divided into at least two parts, the segmented ferrite cores being connected by a flexible connector such as double-coated adhesive tape, or a magnetic powder containing Silicone Rubber. Therefore, when an external force directly acts on the antenna through the housing, the ferrite core can be bent to a certain extent, so that the strip antenna can be prevented from breaking.

Description

The invention relates to a strip antenna, especially a thin ferrite magnetic strip antenna.

A small portable radio housing with a strip antenna for receiving AM waves. This strip antenna is a magnetic core coil. Use a ferrite with strong magnetic permeability as the core. The magnitude of electromagnetic waves received by the antenna is proportional to the cross-sectional area and length of the antenna core. In order to obtain very high sensitivity, a large core is required. However, due to limited installation space, in fact, in a thin portable radio, a long and thin ferrite core 40 as shown in FIG. 5 is used for the strip antenna.

In the case where the strip antenna as described above is mounted in the injection molded casing of the thin radio set against the inner surface of the casing, the external force applied to the casing also acts directly on the strip antenna, causing the ferrite core 40 to break. question. If the ferrite core 40 breaks, the sensitivity of the antenna is reduced or even the function is lost. In addition, there is the danger of broken fragments falling into the printed circuit board, which can have a detrimental effect on other circuit components such as varistors, varistors and the like.

Therefore, in consideration of these problems, it is a primary object of the present invention to provide a strip antenna device which does not break when a radio is subjected to external force even if its ferrite core is thin.

In order to achieve the above object, in the strip antenna device according to the present invention, the ferrite core is at least divided into a first ferrite core 2 and a second ferrite core 3, and in the first ferrite core A flexible connector 4 is arranged between the end face of the body core 2 and the end face of the second ferrite core 3 .

In the strip antenna device of the present invention, since the ferrite core is divided into at least two parts, and the separated ferrite core is connected with a flexible connector, when an external force acts on the antenna, the ferrite core Can be bent to a certain extent. Therefore, the ferrite core may not be broken by an external force, thereby preventing a decrease in radio sensitivity or an antenna function failure due to antenna breakage, and preventing harmful effects of antenna fragments from adhering to other line components.

The contents of the accompanying drawings are briefly introduced as follows.

Fig. 1 is a longitudinal sectional view of a first embodiment of the present invention.

Fig. 2 is a plurality of perspective views for explaining the assembly steps of the first embodiment of the present invention.

Figure 3A is a cross-sectional view of the first embodiment of the present invention assembled in a radio.

Figure 3B is a top view of the first embodiment of the present invention assembled in a radio.

Fig. 4 is a cross-sectional view of the second embodiment of the present invention.

Fig. 5 is a perspective view of a ferrite core used in a conventional strip antenna.

A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a sectional view of the first embodiment of the present invention. Reference numeral 1 denotes the entire antenna device. The strip antenna includes two ferrite cores 2 and 3 . Both ferrite cores 2 and 3 are thin, for example, the length is 25mm and the thickness is 1.4mm. In other words, this embodiment has characteristics equivalent to those of a strip antenna having a length of 50 mm and a thickness of 1.4 mm. The end faces of the two ferrite cores 2 and 3 are connected by a flexible connector 4 . Pressure-sensitive adhesive double coated tape or silicone rubber can be used as the connector 4 . For this example, you can also mix some magnetic powder into the silicone rubber. Reference numeral 5 denotes an adhesive layer interposed between the respective end faces of the ferrite cores 2 and 3 and the connector 4 . The distance between the end faces of the ferrite cores 2 and 3 should be as short as possible, which can be 0.5 to 2 millimeters. For example, at a distance of about 1 mm, the sensitivity of the radio is reduced by about 1 dB. A 1 dB drop in sensitivity is not serious in practice, since the human ear cannot detect a change of 2 to 3 dB.

On the entire length surfaces of the ferrites 2 and 3 connected by the connecting member 4, a synthetic resin film 6 (such as a flexible polyester film of 0.1 mm thick) is adhered via an adhesive layer 7. Due to the existence of the film 6, the two ferrite cores 2 and 3 can be flexibly permanently maintain its position. The primary winding 8 of the antenna is wound approximately in the middle of the ferrite core 2 , and the secondary winding 9 is wound approximately in the middle of the ferrite core 3 .

The first embodiment of the strip antenna device 1 described above is assembled as shown in FIG. 2 . Firstly, the two ferrite cores 2 and 3 shown in FIG. 2A are connected to their end surfaces with a connecting piece 4 to form a shape as shown in FIG. 2B . Next, as shown in Fig. 2C, a flexible synthetic resin film 6 is pasted on the entire one longitudinal surface of the ferrite cores 2 and 3. After the two ferrite cores 2 and 3 are connected into an integral antenna element with a connector 4 and a synthetic resin film, as shown in FIG. 2D, the primary winding 8 and the secondary winding 9 of the antenna coil are wound, so that The strip antenna device 1 is assembled.

Figure 3A shows a cross-sectional view of an embodiment of the present invention installed on a radio. Figure 3B shows a top view of the radio with one half of the housing removed. In FIG. 3, reference numeral 20 denotes a radio case. The casing 20 is made of synthetic resin by injection molding, including an upper cover and a lower cover, and the wall thickness is about 1 mm, for example. The thickness of the entire radio is about 5 mm.

Reference numerals 21 and 22 denote support members made of injection-molded resin such as nylon, which are fitted to both ends of the strip antenna 1, respectively. On the support 21 there is a cutout and a protrusion 23 which projects into a groove which cooperates with the ferrite 2 . Due to the cutout and the existence of the protruding portion 23, it is possible to accommodate the dimensional change in the length of the strip antenna 1 due to bending. The respective thicknesses of the supports 21 and 22 are equal to the internal dimensions of the housing 20 . The support is glued to the housing 20 with an adhesive.

The corresponding protruding ends of the primary winding 8 and the secondary winding 9 of the strip antenna are soldered to printed circuit pattern connections made on the printed circuit board 24 .

Also, it is preferable to apply wax to the outer surface of the strip antenna 1 installed in the above housing 20 when necessary.

The ferrite core 2 and the connecting piece 4 of the ferrite core 3 of the strip antenna 1 installed in the housing 20 are approximately located at half of the width of the housing 20 in size. Therefore, when the case 20 is subjected to an external force, the strip antenna 1 is deformed by bending the connecting piece along with the deformation of the case 20, thereby preventing the ferrite cores 2 and 3 from breaking.

Fig. 4 shows a sectional view of a second embodiment of the present invention. In this embodiment, the ferrite core 2 around which the primary winding 8 is wound and the ferrite core 3 around which the secondary winding 9 is wound are connected by a resin upper support 30 and a resin lower support 31 . The upper supporting member 30 and the lower supporting member 31 respectively have a V-shaped notch 32 and 33 in the middle of the outer surface thereof. In this embodiment, when an external force acts on the upper support 30 and the lower support 31 , the antenna bends at the notches 32 and 33 , thereby also preventing the ferrite cores 2 and 3 from breaking.

In the above-mentioned embodiments, it is also possible to subdivide the ferrite core into two or more segments. And connect the segmented cores into a whole antenna.

Also, in the second embodiment, it is also possible to connect two ferrite cores to form an integral antenna by inserting each ferrite core into a shorter support member. In addition, the present invention is equally applicable to a strip antenna device having a rod-shaped ferrite core.

Since the antenna is divided into at least two ferrite cores, even if an external force is applied to the antenna, breakage can be prevented due to the flexibility or deformation of the antenna with the external force.

Claims (6)

1, a kind of thin bar antenna device, it is characterized in that, have the ferrite fuse of a predetermined length to be divided at least one first ferrite fuse and one second ferrite fuse, and flexible connecting member is disposed between the end face of the end face of the first ferrite fuse and the second ferrite fuse.

2, thin bar antenna device according to claim 1 is characterized in that, above-mentioned connector is a band material that double spread is arranged.

3, thin bar antenna device according to claim 1 is characterized in that, above-mentioned connector is a silicon rubber.

4, thin bar antenna device according to claim 3 is characterized in that, above-mentioned silicon rubber is mixed with Magnaglo.

5, thin bar antenna device according to claim 1 is characterized in that, is stained with one deck film of synthetic resin on a longitudinal terminal surface total length of ferrite fuse.

6, thin bar antenna device according to claim 5 is characterized in that, above-mentioned film of synthetic resin is a polyester.