JPH05343909A - Portable radio equipment - Google Patents

Abstract

PURPOSE:To form an antenna with a higher gain than that of a conventional antenna in a radio equipment having a smaller size than that of a conventional equipment by using the inside of a radio equipment casing, thereby forming a multi-turn type loop antenna with a large aperture area. CONSTITUTION:The antenna 21 is formed by a metallic thin film on the radio equipment casing as a 2-winding loop antenna, a feeding section 25 is connected to a radio printed circuit board 22 through matching capacitors 24a, 24b. A connection section 23 uses the capacitor 24b to connect one end of a loop to an end of other loop. Furthermore, the interval of elements of the loop antenna 21 is 1mm. Thus, since plural number of loop windings are attained by forming the loop antenna to a wide area on the wall face of the radio equipment casing or in the inside of the casing, the small sized radio equipment with high sensitivity is easily realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable wireless device, and more particularly to a microminiature portable wireless device having a high gain antenna.

[0002]

2. Description of the Related Art As a conventional antenna for a small portable wireless device, a small loop antenna is mainly used inside a main body case of a wireless device section. As for the gain of the loop antenna, the antenna gain is almost proportional to the opening area of the antenna. FIG. 18 is a diagram showing an example of a conventional small portable radio, and shows an example of a radio call receiver.

In the figure, 11 is an antenna, 12 is a radio housing, 13 is a display, 14 is a radio circuit board,
Reference numeral 15 represents a battery. The size of the housing is 0.08 ×
It is about 0.05 × 0.01λ. The antenna 47 is a one-turn type loop antenna built in the inside of the housing.
Its size is 0.006 × 0.035λ, 1mmφ
It is composed of a conductive wire of about 5 mm or a conductive plate having a width of about 5 mm. The gain of this antenna 11 in free space is 300M
It is about −20 dBd in the vicinity of Hz, and the gain when worn on the human body is about −17 dBd. Note that dBd is a unit in which the gain of the half-wave dipole antenna is 0.

[0004]

The miniaturization of small portable wireless devices has been advanced due to the progress of electronic circuit technology. Therefore, the volume of the housing is reduced and the space for incorporating the antenna is reduced, so that the antenna gain is reduced. For example, if the housing dimensions are 0.04 x 0.04 x
In the case of a 0.007λ ultra-small radio, the housing size is 0.08
The gain becomes 6 dB or more lower than that of the loop antenna built in the radio of × 0.05 × 0.01λ, and the free space gain becomes about −26 dBd, so that the required communication line quality cannot be maintained. .. Further, in recent years, the degree of component integration inside the housing has also increased, and it has become difficult to find the space for the antenna inside the housing.

In order to increase the aperture area of the loop antenna, there is a method in which the number of turns of the loop antenna formed of a conductive wire is wound a plurality of times. However, in the matching method which is generally used at present, two turns are used. In this case, the impedance, especially the reactance component, becomes large, and the matching capacitor cannot cancel it, so that it falls out of the matching possible range and the antenna cannot be realized. The same applies to the case of three or more windings.

In order to solve such a conventional problem, an object of the present invention is to provide an ultra-small radio device having an antenna having a gain larger than that of the conventional radio device, which is smaller than the conventional radio device.

[0007]

According to the present invention, a multi-turn loop antenna having a large opening area is formed by effectively using the inside of a radio housing. That is, the invention of claim 1 is a portable wireless device having a box-shaped housing, and a wireless device inside the housing, wherein the two facing surfaces of the housing are A plurality of conductive rings formed by depositing a conductive material on two surfaces that are substantially orthogonal to each other and are opposed to each other are separated by a surface parallel to the opening surface of the conductive ring. And a plurality of elements having a U-shaped or C-shaped cross-sectional shape are formed by cutting at least a part of each of the divided conductive rings. The portable wireless device is provided with a multi-turn loop antenna having one end of an element adjacent to the element electrically connected in a diagonal line and an end of the element not connected to the adjacent element serving as a feeding point.

According to a second aspect of the present invention, a plurality of members, which are electrically connected to each other and are electrically connected to each other by a conductive wire or a thin plate made of a conductive material, are arranged in parallel. Then, a plurality of winding loops are formed by electrically connecting diagonally between the adjacent members at the opposite end opposite to the electrically connected end of the member, and electrically connecting the adjacent members to each other. It is a portable wireless device equipped with a multi-turn loop antenna having a feeding point at an end that is not electrically connected.

[0009]

According to the present invention, a high gain antenna is realized by forming a wide multi-turn loop antenna with a large opening area having the above structure in a small portable radio device.
In the present invention, the loop element can be made wider due to its structure as compared with the conventional antenna. As a result, as shown in FIG. 5, it is possible to reduce the logical impedance, particularly the reactance. Therefore, even a loop antenna having a large opening area, such as a loop antenna having a plurality of turns, can be reduced as shown in the equivalent circuit of FIG. A matching circuit that uses different capacitors can match and can be used in practice.

Assuming that the radiation resistance of the antenna is X and the electric resistance on the loop circumference is Y, the efficiency Z of the loop antenna is Z =
It is generally represented by X / (X + Y). Therefore, as in an example of theoretical values of the loop area and the gain calculated as shown in FIG. 4, when the opening area of the loop antenna is increased, the radiation resistance X is increased and the antenna gain is increased. For example,
In the antenna of the embodiment of the present invention, the number of loop turns is set to 2 and the volume of the housing is effectively used, so that the loop area is 20 compared with the conventional receiver antenna shown in FIG.
The gain is high because it can be increased by 0% or more.

When the present invention is used in the ultra-high frequency band or the ultra-high frequency band, the electric resistance depends on the surface area due to the skin effect. In the present invention, since the loop element width can be made several times to several tens of times wider than the conventional one,
The electric resistance Y can be reduced from a few fractions to a few tenths. Therefore, the efficiency of the loop antenna can be significantly increased. Further, the antenna according to the present invention has a wide band characteristic because the element width can be widened. For example, it is possible to obtain a band about three times as large as that in the case of using a thin conductor in the ultra-high frequency band.

[0012]

FIG. 1 is a diagram showing a first embodiment of the present invention. In the figure, reference numeral 21 denotes an antenna, which constitutes a two-turn loop antenna having a width of 23 mm and made of a thin metal film in a radio casing, and a power feeding section 25 has matching capacitors 24a, 24
It is connected to the radio circuit 22 through b. Also, 2
Reference numeral 3 is a connecting portion formed by a capacitor that connects one end of the loop and the other end of the loop. The distance between the elements of the loop antenna is 1 mm. Case size is 47 x 47
× 8 mm, which is 0.04 × 0.04 × when converted to the wavelength.
It is 0.007λ.

FIG. 2 shows an equivalent circuit of the antenna of the embodiment shown in FIG. In an actual device, the matching capacitors 24a and 24b can be easily adjusted if they are variable capacitors. This also applies to the other embodiments described below. FIGS. 6 and 7 show the frequency characteristics of the antenna when it is installed in the free space and in the chest pocket of the human body. Moreover, the antenna pattern in each state is shown in FIG.

In FIG. 8, (a) shows the radiation characteristic in free space, and (b) shows the radiation characteristic when the human body is worn. The maximum gain is -17 dBd in free space as shown in Fig. 3 (a) and the human body as shown in Fig. 2 (b), though the capacity is about 1/3 of that of the conventional receiver. -13.5 dBd when mounted, 3 dB in free space compared to conventional antennas, 3.5 when mounted on the human body
A high gain exceeding dB is realized. Further, VSWR3 has about 4 MHz, which is a wide band.

FIG. 9 is a diagram showing a second embodiment of the present invention, in which 26 is an antenna, 27 is a radio circuit board, 28a,
28b is a loop connection part, 29a, 29b and 29c are matching capacitors, and 30 is a power feeding part. In this embodiment, the loop area can be further increased by setting the number of loop turns to three, and the gain can be increased by about 4.5 dB as compared with the case of one turn.

FIG. 10 is a diagram showing a third embodiment of the present invention, in which 31 is an antenna, 32 is a radio circuit board, 33 is a loop connection part, 34a and 34b are matching capacitors, and 35 is a power feeding part. It represents. In this embodiment, the impedance element electrically connecting the loops is replaced with a conductive wire, and the impedance is concentratedly loaded in the feeding portion, thereby realizing an antenna pattern different from that of the first embodiment in the free space. is doing.

FIG. 11 shows an equivalent circuit of this antenna, and FIG. 12 shows an antenna pattern when the antenna is mounted in a free space and a human chest pocket. In FIG. 12, (a) shows the radiation characteristic in free space, and (b) shows the radiation characteristic when the human body is worn. FIG. 13 is a diagram showing a fourth embodiment of the present invention, in which 36 is an antenna, 37 is a display, and 3 is a display.
8 is a radio circuit board, 39 is a loop connection part, 40a, 40
Reference numeral b represents a matching capacitor, and 41 represents a power feeding unit.

It has been confirmed that even if holes such as a display and a switch are formed in the antenna 36 as shown in this embodiment, the characteristics substantially the same as those of the first embodiment can be obtained. FIG. 14 is a diagram showing a fifth embodiment of the present invention,
42 is an antenna, 43 is a radio circuit board, 44 is a loop connection part, 45a and 45b are matching capacitors, and 46 is a matching capacitor.
Indicates a power feeding unit.

The embodiment described above corresponds to claim 1, and is a case in which a thin metal film is applied to the housing to form a loop antenna, and the embodiment described below. In the case where the portable wireless device uses a casing made of an insulating material such as plastic, a loop antenna formed of a thin conductive thin plate is provided inside the casing. This is the invention of claim 2. It corresponds to. Also in this case, the same characteristics as those in the above-mentioned respective embodiments can be obtained.

A sixth embodiment of the present invention is shown in FIG. In the figure, (a) is a perspective view, (b) shows a state in which the wireless device is taken out from the housing, 52 is a wireless circuit board,
53 is a power feeding part, 54 is a conducting wire, 55 is a U-shaped metal plate,
56 is a pattern on the circuit board for connecting the antenna elements, and 57 is a case. In this embodiment, a loop antenna is constructed by using a U-shaped metal plate 55 having a size that can be accommodated inside a housing made of an insulating material such as plastic.

FIG. 16 is a diagram showing a seventh embodiment of the present invention, and shows an example in which a loop antenna is constructed by connecting opposing metal plates with a conductive wire. In the figure, reference numeral 58 is a wireless circuit board, 59 is a power feeding portion, 60 is a conducting wire, 61 is a metal plate, and 62 is a pattern on the circuit board. In this way, the antenna of the present invention can also be configured by holding the metal plates facing each other on the two surfaces in the housing and connecting them with the connecting conductor.

FIG. 17 is a diagram showing an eighth embodiment of the present invention, which shows a case where a loop antenna is formed by a thin metal plate spread on the surface of a circuit board.
Is a circuit board, 64 is a feeding part, 65 is a conducting wire, 66 is a metal plate spread on the circuit board, and 67 is a conducting wire connecting the metal plates spread on the circuit board in a diagonal pattern. There is. With this configuration, it is also possible to adopt a structure in which another circuit board is inserted between both circuit boards. As described in the above description of the embodiments, the antenna of the present invention can control the impedance by changing the width of the loop portion and the gain by changing the electric resistance.

[0023]

As described above, according to the present invention, the loop antenna can be formed on the wall surface of the radio equipment housing or in the area having a large area inside the housing, and the number of loop turns can be reduced. Since it can be performed a plurality of times, a compact and highly sensitive radio can be easily realized. For example, even in the case of a loop antenna with two turns, a gain improvement of 3 to 4 dB is expected as compared with a conventional radio device, which enables downsizing and power saving of the radio device, and a margin for a wireless line. Can have

As a result, the communication quality can be improved and the communication area can be expanded. Further, since the band is wide, it is possible to omit an antenna adjustment mechanism and the like when switching channels, and thus it is possible to reduce gain deterioration due to the loss, reduce the size of component space, and reduce cost. ..

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the antenna of the first embodiment.

FIG. 3 is a diagram showing a relationship between a loop area and a gain.

FIG. 4 is a diagram showing a relationship between a loop area and a gain.

FIG. 5 is a diagram showing a relationship between a loop element width and an antenna impedance.

FIG. 6 is a diagram showing frequency characteristics in free space according to the first embodiment.

FIG. 7 is a diagram showing frequency characteristics when the human body of the first embodiment is worn.

FIG. 8 is a diagram showing an antenna radiation characteristic of the first embodiment.

FIG. 9 is a diagram showing a second embodiment of the present invention.

FIG. 10 is a diagram showing a third embodiment of the present invention.

FIG. 11 is a diagram showing an equivalent circuit of the antenna of the third embodiment.

FIG. 12 is a diagram showing an antenna radiation characteristic of a third embodiment.

FIG. 13 is a diagram showing a fourth embodiment of the present invention.

FIG. 14 is a diagram showing a fifth embodiment of the present invention.

FIG. 15 is a diagram showing a sixth embodiment of the present invention.

FIG. 16 is a diagram showing a seventh embodiment of the present invention.

FIG. 17 is a diagram showing an eighth embodiment of the present invention.

FIG. 18 is a diagram showing an example of a configuration of a conventional portable wireless device.

[Explanation of symbols]

21, 26, 31, 36, 42 Antenna 22, 27, 32, 38, 43, 52, 58 Wireless circuit board 23, 28a, 28b, 33, 39, 44 Loop connection part 24a, 24b, 29a, 29b, 29c, 34a, 3
4b, 40a, 40b, 45a, 45b Matching capacitors 25, 30, 35, 41, 46, 53, 59, 64
Power supply unit 37 Display 54, 60, 65, 67 Conductive wire 55 U-shaped metal plate 56, 62 Pattern on circuit board 57 Case 61 Metal plate 63 Circuit board 66 Metal plate spread on circuit board

Claims (2)

[Claims] 1. A portable wireless device having a box-shaped housing, and a wireless device incorporated inside the housing, the two facing surfaces of the housing, and the two surfaces facing each other. A conductive ring formed by depositing a conductive material on two surfaces which are orthogonal to each other and are opposed to each other is divided into a plurality of parts with a surface parallel to the opening surface of the conductive ring as a boundary. , A plurality of elements having a U-shaped or C-shaped cross-sectional shape is formed by cutting out at least a part of each of the divided conductive rings, and one end of the notched portion of the element is adjacent to the element. A portable wireless device comprising: a multi-turn loop antenna having one end of an element electrically connected in a diagonal line and having an end not connected to an adjacent element as a feeding point. 2. A thin plate made of a conductive material is made to face each other, and a plurality of members whose ends are electrically connected by a conductive wire or a thin plate made of a conductive material are arranged in parallel. At the end opposite to the end connected to, the adjacent members are electrically connected diagonally to form a loop of multiple turns, and the end not electrically connected to the adjacent member is formed. A portable wireless device comprising a multi-turn loop antenna provided with a feeding point.