JPH0634316U - Loop antenna - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide a loop antenna with improved reception sensitivity that can be applied to conventional products without design changes. [Structure] In a loop antenna in which a conductor 1 is formed in a loop shape, a magnetic layer 3 is formed on a frame 2 around which the conductor 1 is wound by an adhesive or resin tape mixed with magnetic powder. [Effect] Regardless of the shape or product of the loop antenna, it is possible to easily form a magnetic layer on the frame without changing the design, and the magnetic field magnetism increases the intensity of radio waves interlinking with the conductor. Therefore, the receiving sensitivity of the antenna is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a loop antenna capable of improving reception sensitivity.

[0002]

[Prior art]

 A loop antenna formed by winding a conductor in a loop is often used as a directional antenna only for reception. The loop antenna has the advantage that the reception frequency band can be widened, but there is a limit to improving the reception sensitivity because the conductor is simply wound around the frame.

The inventor of the present invention previously proposed in Japanese Patent Application No. 4-34569 a loop antenna in which a magnetic material is arranged on a surface surrounded by conductors. The loop antenna disclosed in Japanese Patent Application No. 4-34569 is designed so that a molded magnetic body is incorporated in a space inside a frame around which an antenna conductor is wound. Therefore, in order to apply the above idea to conventional products, some design changes may be required.

[0004]

[Problems to be solved by the device]

 An object of the present invention is to provide a loop antenna with improved reception sensitivity that can be easily applied to conventional products without design changes.

[0005]

[Means for Solving the Problems]

 The present invention is characterized in that, in a loop antenna in which a conductor is formed in a loop shape, a magnetic layer is formed on a frame by an adhesive or resin tape mixed with magnetic powder.

[0006]

【Example】

 FIG. 1 shows a cross-sectional view of an embodiment of the loop antenna of the present invention. Reference numeral 1 is an antenna conductor, 2 is an ordinary resin frame, and 3 is a magnetic layer made of an adhesive mixed with magnetic powder. The present inventors conducted an experiment using ferromagnetic ferrite powder as the magnetic powder and epoxy adhesive as the adhesive, and found that the content of the magnetic powder was about 70 wt% and the thickness of the magnetic layer was about In the case of 0.5 mm, the receiving sensitivity is improved by about 2.5 dB as compared with before forming the magnetic layer.

FIG. 2 shows another embodiment of the present invention. Reference numeral 4 is a magnetic layer formed by winding a resin tape mixed with magnetic powder on a frame. The same parts as those in FIG. 1 are given the same numbers. The magnetic layer formed on the frame in this way concentrates the radio waves in the air by its magnetism and increases the radio wave intensity interlinking with the conductor, so that the receiving sensitivity as an antenna is improved. An adhesive or resin tape mixed with magnetic powder can easily form a magnetic layer on the frame regardless of the shape of the loop antenna or the product.

Although the example using the epoxy adhesive is shown in the embodiment of FIG. 1, the present invention is not limited to this. For example, when using an adhesive with a viscosity lower than that of an epoxy adhesive, cloth-like tape is impregnated with the adhesive to prevent dripping and unevenness, and the tape is shown in Fig. 2. As described above, it is preferable to use a means for wrapping around the frame body. In the embodiments of FIGS. 1 and 2, the magnetic layer is formed on the winding portion of the antenna conductor of the frame body, but the magnetic conductor is formed inside the loop of the antenna conductor. The magnetic layer may be formed anywhere.

[0009]

[Effect of device]

 As described above, the loop antenna of the present invention is one in which the magnetic layer is formed on the frame by the adhesive or resin tape mixed with the magnetic powder. As a result, the magnetic layer can be easily formed on the frame regardless of the shape and product of the loop antenna, and no design change is required. Further, the magnetic sensitivity of the formed magnetic layer improves the receiving sensitivity of the antenna.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the loop antenna of the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the loop antenna of the present invention.

[Explanation of symbols]

 1 Antenna conductor 2 Frame 3 Magnetic layer made of adhesive mixed with magnetic powder 4 Magnetic layer made of resin tape mixed with magnetic powder

Claims (2)

[Scope of utility model registration request] 1. A loop antenna in which a conductor is formed in a loop shape, wherein a magnetic layer is formed on a frame body by using an adhesive agent in which magnetic powder is mixed. 2. A loop antenna in which a conductor is formed in a loop shape, in which a resin tape mixed with magnetic powder is attached to the frame body to form a magnetic layer on the frame body.