JPH052425U - Loop antenna - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a loop antenna for a small portable wireless device which has a small gain and a high gain even in a small portable wireless device. [Structure] According to the structure of the present invention, in the loop antenna (21) in which the element is composed of a strip-shaped conductor, the element (21)
A conductive protrusion (25) is provided on the surface of the element (21) of the loop antenna along the loop direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention relates to a loop antenna, and more particularly, to a loop-shaped loop antenna of a micro portable radio device. About antenna.

[0002]

[Prior art]

  The antennas of small portable radios whose shape is sufficiently smaller than conventional wavelengths are mainly A small loop antenna is used for. Loop antenna of the small portable radio It is important to reduce the resistance of the antenna element in order to improve the efficiency of the antenna. is there. Therefore, if you widen the width of the loop element of the loop antenna, Since the resistance component in the tenor element is small, the antenna efficiency is high.

[0003]   FIG. 14 shows an example of a loop antenna of a conventional portable wireless device. In the figure, 46 is Anne Indicates a tena element. A small portable type with such a loop antenna built-in In the case of a wire machine, the antenna element is band-shaped and the resistance component is reduced to reduce antenna efficiency. There is a small portable radio that is raising the market.

[0004]

[Problems to be solved by the device]

  However, the miniaturization of small portable wireless devices has progressed due to the progress of electronic circuit technology. The area of the built-in loop antenna is small. The surface of the element is also small. For this reason, even with a strip-shaped antenna There is a problem that the antenna gain cannot be secured.   The present invention has been made in view of the above points, and has been made in a small portable wireless device as compared with the conventional one. To provide a loop antenna for a small portable radio with high gain To aim.

[0005]

[Means for Solving the Problems]

  In a loop antenna where the element is composed of strip conductors, A conductive plate-shaped protrusion is provided along the loop direction to form an element of the loop antenna. Prepare for the surface.   In addition, part or all of the loop antenna element surface should be Bend along the direction.   Further, the element has a shape folded back along the edge in the loop direction.

[0006]

[Action]

It is generally known that the efficiency A of a loop antenna, which is smaller than the wavelength, is represented by A = X / (X + Y), where X is the radiation resistance of the antenna and Y is the electrical resistance on the loop circumference. Here, as one of the methods for increasing the antenna efficiency, a method for reducing the electric resistance Y is considered. At frequencies above the ultra-high frequency band in which portable radios are used, current flows on the surface of the conductor due to the skin effect, so that the electric resistance depends only on the area of the conductor surface. Here, as a method of reducing the electric resistance, there is a method of increasing the surface area of the conductor. In the present invention, in a limited space, a band-shaped loop antenna is constructed by a conductor or a conductive plate inside the portable radio device housing, or a band-shaped loop antenna is constructed by a conductive material on the front surface or the back surface of the housing. There are things. In this way, the conductor surface area is effectively increased. FIG. 15 is a graph showing the relationship between the conductor surface area and the conductor resistance. This figure shows data relating to the loop antenna shown in FIG. The shape of the antenna in FIG. 16 is 0.07λ in the loop direction, 0.008λ in the vertical direction, the width of the loop antenna is a, and the thickness of the loop antenna is b. The vertical axis of the graph in FIG. 15 represents the resistance (Ω) of the loop at a frequency of 300 MHz, and the horizontal axis represents the peripheral length (2a + 2b) × 10 ⁻³ λ of the cross-sectional shape of the loop element. As can be seen from the graph of FIG. 15, the surface area increases and the loop resistance decreases as the peripheral length increases.

[0007]   In addition, the antenna element is formed into a surface by forming a conductor in an I shape or a convex shape. The product increases and the electric resistance decreases, so the antenna efficiency can be increased and the high gain Can realize an antenna. In addition, the present invention can The effect can be obtained even if it is done separately.

[0008]

【Example】

  FIG. 1 shows the configuration of a loop antenna according to the first embodiment of the present invention. The configuration of FIG. 1 is wireless Inside the machine housing 24, the loop antenna 21, the power feeding section 22, the radio circuit 23, and the loop are provided. The conductive plate-shaped protrusion 25 provided in the loop direction inside the antenna 21 Become The protrusion 25 having a plate-like protrusion structure is a loop inside the loop antenna 21. They are vertically arranged along the direction and are provided so that their cross-sectional shape is T-shaped. As a result, the surface area of the element surface of the loop antenna 21 is increased and the conductor resistance is increased. Get smaller.

[0009]   FIG. 2 shows the configuration of the loop antenna of the second embodiment of the present invention. 2 shows a protrusion 27 Is the installation position on the element of the inside of the loop antenna 21 shown in FIG. This is the configuration when the position is changed from the outside to the outside. The direction of the protrusion 27 changes, and the loop It is provided outside the antenna 21. The protrusion 27 is installed outside the loop antenna. Since the surface area does not change even if it is eclipsed, the surface area is The conductor resistance decreases as the product increases. Also, as in the case of FIG. As the cross-sectional shape of the surface of the ment increases, the surface area increases and the conductor resistance increases. Since the resistance is small, the effect is high.

[0010]   FIG. 3 shows the configuration of the loop antenna of the third embodiment of the present invention. Figure 3 is a loop The protrusions 48, 48 'on the tenor 21 are not flush with the loop antenna 21. And the loop antenna 21 has a reduced surface area. The present invention can be realized without any trouble.

[0011]   FIG. 4 shows the case where the loop antenna according to the first embodiment of the present invention is incorporated in a housing without a mobile phone. The structure of a wire machine is shown. The figure shows a plate-shaped protrusion 31 in the loop direction on the portable radio casing 24. Are provided at four positions above and below the inside of the loop antenna. Lupuan in the figure The tenor has the same surface area and gain for the same reason as the structure shown in FIG. To do.

[0012]   FIG. 5 is a graph showing the difference in gain between the present invention and the conventional loop antenna. The same figure 5 is a model of the loop antenna having the configuration of FIG. In the figure, the vertical axis is the conventional It is the gain difference (dB) from the antenna, and the horizontal axis is the protrusion of the loop antenna. Indicates a number. In the figure, graph a shows the gain of the present invention, and b shows the conventional gain with no protrusion. The gain of a type loop antenna is shown. The antenna size of this model is approximately 0.07 × 0.005 × 0.008λ, the height of the protrusion is about 0.001λ is there. By increasing the number of protrusions from this graph, the resistance of the antenna is reduced. It can be seen that the gain is improved. In addition, as shown in FIG. However, the area of the loop element is reduced effectively, but in the example of Fig. The effect of gain improvement can be obtained by attaching two or more. In addition, the protrusion Even if they are provided, as shown in Fig. 3, the protrusions should be on the same loop element. Staggered configurations that do not result in a flat surface can almost always reduce the loop area. Absent.

[0013]   FIG. 6 shows the configuration of the loop antenna of the fourth embodiment of the present invention. This example is a loop A rod-shaped protrusion 33 is provided in the direction, and a convex loop antenna 32 is formed. Is made. If multiple protrusions are provided and unevenness occurs multiple times, the gain will be further increased. It The gain when the number of irregularities of the antenna according to the present invention is changed, and the conventional strip shape The difference in the gain of the antenna is as shown in FIG. 5 because the surface area is the same as that of the T type. . This embodiment reduces the resistance of the antenna and increases the gain of the antenna. It

[0014]   FIG. 7 shows the configuration of the loop antenna of the fifth embodiment of the present invention. This embodiment is shown in FIG. This is a configuration in which a plurality of rod-shaped protrusions 33 of the configuration are provided. Unevenness like this protrusion 35 The antenna gain is proportional to the number of Further improve.

[0015]   FIG. 8 shows a structure in which the loop antenna of the sixth embodiment of the present invention is incorporated in a portable radio device casing. Indicates success. The wireless circuit board 37 is sandwiched inside the portable wireless device housing 36, and This is a configuration in which the protruding portion 39 is provided. In the case of this embodiment, the bar-shaped protrusion 39 is It is provided in two places on the upper part of the tenor element and two places on the lower part. is there. In the case of the figure, the wireless circuit board 37 is provided so as to face each other. , Do not have to be provided at opposite positions. Even with this configuration, there are multiple uneven parts. Since the number of turns is increased, the surface area is substantially increased, the conductor resistance is reduced, and The profit is improved.

[0016]   FIG. 9 shows the configuration of the loop antenna of the seventh embodiment of the present invention. This example is a loop The loop element 40 is bent in the same direction so that the bent cross section is V-shaped. Of. This allows you to have no protrusions on the loop antenna element The surface area can be increased and the antenna gain is improved.

[0017]   FIG. 10 shows the structure of the loop antenna of the eighth embodiment of the present invention. In this example, The protrusion 42 is partially provided on the loop element. same As shown in the figure, the antenna gain is improved even if it is partially provided.

[0018]   FIG. 11 shows the configuration of the loop antenna of the ninth embodiment of the present invention. In this example, Bend the end of the loop element in the loop direction so that there is an overlap on the loop element. It is a double one. It is a loop to duplicate the loop element 43 The elements may or may not overlap completely from end to end. Good. In this embodiment, the loop element 43 is formed by bending the loop element 43 on the upper side of the element. Weighting increases the effective thickness and increases the surface area.   FIG. 12 shows the structure of a loop antenna according to the tenth embodiment of the present invention. In this example, From the upper end c of the loop element 44 to the upper element of the loop antenna. It is bent so that it completely overlaps, and the surface area of the upper element is Since it is more than doubled, the antenna gain is improved.   FIG. 13 shows the structure of a loop antenna according to the eleventh embodiment of the present invention. In this example, By providing another element inside the supplement 45, the same structure as that of FIG. Similarly, the surface area is increased and the antenna gain is improved.   The embodiments shown in FIG. 11 to FIG. 13 are effective in making the element thickness of the loop antenna effective. The thickness of the element is doubled. The narrower the space between the elements in the area, the better the loop area can be secured. High gain can be obtained.

[0019]   Even if the loop antenna is a multi-turn type such as a 2-turn type or a 3-turn type, Similar to the above example, increasing the surface area and thereby reducing conductor resistance More effective.

[0020]

[Effect of device]

  As described above, according to the present invention, the loop antenna is configured in the portable wireless device housing, and Large display and various switches can be built in, and small size and high sensitivity It is possible to realize a wireless device having. With this invention, compared to the conventional portable radio , 1 to 2 dB gain improvement is expected, and it is possible to reduce the size and power consumption of wireless devices. Margin can be added to the wireless line to improve communication quality and improve communication area. It can be expanded.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a loop antenna according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a loop antenna according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a loop antenna according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a portable wireless device when the loop antenna according to the first embodiment of the present invention is incorporated in a housing.

FIG. 5 is a graph showing a difference in gain between the present invention and a conventional loop antenna.

FIG. 6 is a configuration diagram of a loop antenna according to a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a loop antenna according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a loop antenna according to a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram of a loop antenna according to a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram of a loop antenna according to an eighth embodiment of the present invention.

FIG. 11 is a configuration diagram of a loop antenna according to a ninth embodiment of the present invention.

FIG. 12 is a configuration diagram of a loop antenna according to a tenth embodiment of the present invention.

FIG. 13 is a configuration diagram of a loop antenna according to an eleventh embodiment of the present invention.

FIG. 14 is a diagram showing an example of a loop antenna of a conventional portable wireless device.

FIG. 15 is a graph showing the relationship between conductor surface area and conductor resistance.

16 is a diagram showing a loop antenna which is the data of the graph of FIG.

[Explanation of symbols]

21,26,32,34,40,41,43,44,4
5, 46, 47 Antenna 22, 29, 38 Feeding section 23, 30, 37 Radio circuit board 24 Radio housing 25, 27, 31, 33, 35, 39, 42, 48 Projection 28, 36 Housing and antenna

Claims (3)

[Scope of utility model registration request] 1. A loop antenna, the element of which is composed of a belt-shaped conductor, wherein a plate-shaped or rod-shaped protrusion is provided on the element surface of the loop antenna along the loop direction of the element. antenna. 2. A loop antenna in which an element is composed of a strip-shaped conductor, wherein a part or all of the element surface of the loop antenna is bent along the loop direction of the element. 3. A loop antenna in which an element is composed of a strip-shaped conductor, wherein the element has a shape folded along an edge in a loop direction.