APPRESSED ANTENNA

Abstract

An appressed antenna includes an antenna housing and a metal shell. The antenna housing comprising a housing and a planar antenna, where the planar antenna is bent with one part folded onto the inner surface of the housing and other part pressed onto the outer surface of the housing. The antenna housing is sleeve fitted to the metal shell with a gap between for the planar antenna to radiate. In this all-metal environment, the position of the antenna is close to the gap opening will increase radiation efficiency. By having at least a branch at the tail end of the appressed antenna, the appressed antenna can have a good return loss and antenna gain.

Claims

1. An appressed antenna, including: an antenna housing, comprising a housing and a planar antenna, wherein part of the planar antenna is pressed onto the outer surface of the housing, and the other part is folded onto the inner surface of the housing; and a metal shell, being larger than the antenna housing, and the antenna housing is sleeved into the metal shell, and the distance between the antenna housing and the metal shell is greater than 0.

2. The appressed antenna of claim 1, wherein the distance between the antenna housing and the metal shell is between 2 mm and 3 mm where the planar antenna is disposed.

3. The appressed antenna of claim 1, wherein the metal shell is made of metal or surface treated with metal material.

4. The appressed antenna of claim 1, wherein the planar antenna is an inverted-F shaped and contains LCP material.

5. The appressed antenna of claim 1, wherein the planar antenna comprises of a ground terminal, a feed terminal and a plurality of branches.

6. The appressed antenna of claim 5, wherein the planar antenna is bent, the ground terminal and the feed terminal are folded onto the inner surface of the housing, and the plurality of branches are pressed onto the outer surface of the housing.

7. The appressed antenna of claim 5, wherein at least the ground terminal, feed terminal and branches of the planar antenna are wrapped with protective film.

8. The appressed antenna of claim 1, wherein the planar antenna is designed based on Zigbee.

9. The appressed antenna of claim 1, wherein the operating frequency of the planar antenna is 2.4 GHz to 2.46 GHz.

10. The appressed antenna of claim 1, wherein at least one slot is opened on the metal shell for radiation of signal waves.

11. The appressed antenna of claim 10, wherein the slot opened on the metal shell exposes at least part of the branches of the planar antenna when the antenna housing and the metal shell are sleeve fitted.

12. The appressed antenna of claim 11, wherein the width of the slot is 2 mm to 3 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a structural diagram of an antenna according to an embodiment of this application;

[0019] FIG. 2 is a schematic structural diagram of a metal shell of a smart switch;

[0020] FIG. 3 is a front view of an antenna cover plate;

[0021] FIG. 4 is a schematic diagram of the inside of the antenna cover plate;

[0022] FIG. 5 is a diagram of a horizontally placed antenna (hard board);

[0023] FIG. 6 is a diagram of a vertically placed antenna (soft board);

[0024] FIG. 7 is a frequency response diagram of an antenna return loss;

[0025] FIG. 8 is a 3D radiation pattern of an antenna gain; and

[0026] FIG. 9 is a schematic diagram of an antenna placed on an inner bottom side of the metal shell.

DETAILED DESCRIPTION

[0027] Referring to FIG. 2, FIG. 3 and FIG. 4, the present invention provides an appressed antenna including a metal shell 1 and an antenna housing 2. The antenna housing 2 includes a housing 3 and a planar antenna 4, where the planar antenna 4 is bent, one part is folded onto the inner surface of the housing 3, and the other part is pressed onto the outer surface of the housing 3. The antenna housing 2 is sleeved into the metal shell 1 and the distance there between is greater than 0, hence at least a gap 2A is maintained.

[0028] The planar antenna 4 is made of a soft material and bent. In this embodiment, the planar antenna 4 contains LCP material.

[0029] In this embodiment, the planar antenna 4 includes a ground terminal 5, a feed terminal 6, and an antenna branch 7. The planar antenna 4 as shown in FIG. 3 and FIG. 4 is bent, the ground terminal 5 and the feed terminal 6 are folded onto the inner surface of the housing 3, and the branch 7 is pressed onto the outer surface on a side of the housing 3.

[0030] In some embodiments, as shown in FIG. 9, a planar antenna 4 is bent, and a ground point 5 and a feed point 6 are folded onto the inner bottom surface of the housing 3, and the branch 7 is pressed onto a top surface of the housing 3.

[0031] In some embodiments, the planar antenna 4 is bent, the ground terminal 5 and the feed terminal 6 are folded onto the inner surface of the housing 3, and the branch 7 is pressed to the outer surface on the edge wall of the antenna cover plate 3.

[0032] In this embodiment, the planar antenna 4 is designed in a planar inverted-F antenna (PIFA) shape. As shown in FIG. 1, the ground terminal 5 and the branch 7 at the tail end of the planar antenna 4 provide a good antenna matching. The planar antenna 4 is designed with LCP material for the LCP material has properties of low loss and low water absorption, and is capable of being shaped after being heated, allows more stable properties and bendable applications of the planar antenna 4.

[0033] In this embodiment, the antenna path of the planar antenna 4 is wrapped with a protective film. That is, the ground terminal 5, feed terminal 6 and antenna branches 7 are all covered with protective film. The planar antenna 4 is designed based on Zigbee and has an operating frequency of 2.4 GHz to 2.46 GHz.

[0034] In this embodiment, the size of the antenna housing 2 is smaller than the size of the metal shell 1. The antenna housing 2 is sleeved into the metal shell 1, and the gap 2A of 2 mm to 3 mm is there between.

[0035] In this embodiment, the metal shell 1 is made of metal or has surfaces treated with metal material. The antenna housing 2 may be made of metal, or plastic such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, and acrylonitrile-butadiene-styrene copolymer, and/or have surfaces treated such as sprayed or electroplated with a metal material, so that the surfaces have a metallic finish.

[0036] In other embodiments, if the bending part of the planar antenna 4 is longer, or longer than a edge of the housing 3, the bending part of the antenna can be bent several times, so that the ground terminal 5 and the feed terminal 6 are folded onto the inner surface of the housing 3, and the antenna branch 7 is pressed onto the outer surface of the housing 3.

[0037] In this embodiment, as shown in FIG. 2, the antenna housing 2 is surrounded by the metal shell 1. The gap 2A with the width about 2.5 mm between the metal shell 1 and the antenna housing 2. The planar antenna 4 can radiate through the gap 2A. Because the antenna is designed in the form of a PIFA, the planar antenna 4 further has a ground terminal 5 in addition to a feed terminal 6.

[0038] In some embodiments, the gap 2A may be different sizes to adapt to different frequencies. For example, the gap 2A may be 2 mm or 3 mm to have optimized radiation effects.

[0039] In some embodiments, the metal shell 1 may have a slot 1A for improved radiation performance. The slot 1A on the metal shell 1 may have different sizes to adapting to different frequencies. For example, the slot 1A may be 2 mm or 3 mm to have optimized radiating effects. There may be a plurality of slots and have additional functions such as heat dispatch.

[0040] In some embodiments, the slot 1A of the metal shell 1 may be designed to resonate with the planar antenna 4 and act as part of the planar antenna 4. Furthermore, the slot 1A corresponds to the antenna branches to have optimized radiating effects. The slot 1A may partially or completely reveals the antenna branches 7 of the planar antenna 4. The quantities, positions and sizes of the slot 1A may vary depending on the design requirements and optimal performance.

[0041] In some embodiments, as shown in FIG. 5, the feed terminal 5 of the planar antenna 4 is in a horizontal plane, but the majority of the planar antenna 4 in a vertical plane perpendicular to the upper cover. Therefore, bendable LCP material is more suitable for such antenna design as compared to the conventional hard FR4 material.

[0042] Furthermore, the planar antenna 4 is bent, the ground terminal 5 and the feed terminal 6 are folded onto the inner surface of the housing 3, and the antenna branch 7 is pressed onto the outer surface of the housing 3.

[0043] In this embodiment, as shown in FIG. 5, the planar antenna 4 may only be placed horizontally when designed with a conventional hard board. In contrast, the planar antenna 4 may be bent and placed vertically as shown in FIG. 6. The planar antenna 4 is disposed between the metal shell 1 and the antenna housing 2, and close to the gap 2A to improve radiation ability of the planar antenna 4.

[0044] In this embodiment, when the housing 3 is sleeve fitted to the metal shell 1, the antenna branch 7 is pressed onto the outer surface of the housing 3, and the antenna branch 7 is aligned with the gap 2A. The feed position of the planar antenna 4 is inside the housing 3, and the planar antenna 4 is turned into a vertical plane after reaching an edge along the housing 3, to be approximate to the gap 2A on the metal shell 1 for improved radiation.

[0045] In this embodiment, in an all metal shell, by using the soft board LCP, the planar antenna 4 is designed into a planar inverted-F antenna and has an operating frequency of 2.4 GHz to 2.46 GHz.

[0046] In this embodiment, the antenna has a center frequency of 2.43 GHz, a return loss of −31.43 dB, and a bandwidth of 2.46%. The simulation response diagram of the antenna is shown in FIG. 7. Through a comparison between the planar antenna 4 being placed horizontally with the hard board and being placed vertically with the soft board, the vertical placement of the planar antenna 4 with the soft board has better antenna matches. FIG. 8 shows a 3D field radiation pattern of the planar antenna 4 at 2.4 GHz surrounded by metal shell 1, the antenna gain reaches 7.2 dBi. The results indicate that the planar antenna structure according to the present invention works effectively in an all metal environment.

[0047] In this embodiment, the planar antenna 4 is designed into the planar inverted-F antenna (PIFA). There are a feed terminal 6 and a ground terminal 5 in a feed plane. In this embodiment, the feed terminal 6 has a longer path than that of the ground terminal 5. Most of the antenna structure is vertically disposed and there are two branches 7 at the tail end of the planar antenna 4. The main function of the branches 7 is to match the antenna. The antenna branches 7 are pressed to the outer surface of the housing 2 and aligned with the gap 2A. The gap 2A partially or completely exposes the antenna branches 7 for improved radiation.

[0048] In summary, the present invention provides the appressed antenna structure where the planar inverted-F antenna with the LCP material in a metal antenna housing 2. The ground terminal 5 and the antenna branch 7 at the tail end of the planar antenna 4 provide a good matching for the antenna. Because the LCP has the thermoplastic property, the antenna can be bent and arranged on different dimensions.

[0049] In the present invention, the planar antenna 4 is bent, so that the planar antenna 4 may be close to the gap 2A to improve the radiation efficiency of the planar antenna 4. The LCP material provides the advantage of being bendable, and further provides low loss and a low water absorption properties, so that the appressed antenna retains a good return loss.