JPH04287409A - Small sized radio equipment - Google Patents

Abstract

PURPOSE:To make the radio equipment having a built-in antenna small. CONSTITUTION:A so-called inverse-F type antenna is adopted for the antenna, in which a narrower gap than the wavelength is provided and which has a ground plate 4b and a radiation element 4a connected to each other at least by one position. Circuit components of the radio equipment are arranged between the two conductor plates 4a, 4b of the antenna and large sized metallic components in the circuit components are arranged at a position apart from the connection position between two conductor plates. The radio equipment is made small by integrating the circuit components and the antenna.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact radio device having a compact and high-performance built-in antenna.

0002

2. Description of the Related Art FIG. 2 shows an example of a conventional small radio device having a built-in antenna, in which 1 is a radio circuit component, 2 is a battery, 3 is a case, 7 is a loop antenna, and 8 is a matching circuit. With this configuration, the antenna cannot be large enough, and since it is close to internal circuit components and large metal components such as batteries and filters, the gain and gain are affected by these components.
Bandwidth characteristics were also poor. Furthermore, since the antenna was small compared to the wavelength, it did not self-resonate and required a matching circuit, further reducing the gain.

FIG. 3 shows another example of a conventional built-in antenna, in which 1 is a radio circuit component, 2 is a battery, 3 is a case, and 4a, b.
is the antenna's radiating element, the conductor plate that acts as the ground plane, 5
is a connection point of the conductor plate, 6 is a power supply line, and 8 is a matching circuit. In such a configuration, the antenna can be relatively large, but not large enough to cause self-resonance, and furthermore, it is designed to be as unaffected by internal metal parts as possible. Therefore, a matching circuit is required and the gain is reduced.

0004

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the disadvantage that conventional small radios with built-in antennas cannot obtain high gain, and to provide a compact radio with small and high performance built-in antennas. Our goal is to provide the following.

[0005]

[Means for Solving the Problems] The present invention is characterized by an antenna in which two conductor plates are connected at least at one point and have a narrow interval compared to the wavelength, one of which serves as a ground plane and the other serves as a radiating element. In the small radio device, at least a part of the circuit components constituting the radio device is arranged between the two conductor plates, and the large metal components among the circuit components are separated from the connection point of the two conductor plates. It is a small radio device that is placed at a certain position and has an antenna that resonates by itself.

[0006]

[Operation] The present invention incorporates the entire radio circuit section between the ground plane conductor and the antenna having the radiation conductor, which are connected on one side, and arranges the large metal parts on the opposite side of the connection point.
Large metal parts operate as part of the antenna,
To provide a small radio device that obtains high gain by self-resonance and has a small and high-performance built-in antenna.

[0007]Thus, the above object is achieved.

[0008]

[Embodiment 1] FIG. 1 shows a first embodiment of the present invention.
2 is a radio circuit component, 2 is a battery, 3 is a case, 4a and 4b are radiation elements of an antenna, a conductor plate that operates as a ground plane, 5 is a connection point of the conductor plate, and 6 is a feeder line. With this configuration, the battery, which is a large metal component, functions as part of the antenna, and since the antenna self-resonates, a matching circuit is not required and high gain can be obtained.

Regarding a plate-shaped inverted F antenna, which is a typical example of an antenna in which two conductor plates connected at a certain point (stub) act as a radiating element and a ground plane, respectively, the metal between the two conductor plates FIG. 4 shows the relationship between the block position and the resonant frequency. Figure 4(a) shows the antenna structure, and Figure 4(b)
is the resonant frequency characteristic. Although this is the case in a small metal casing, the basic characteristics are considered to remain unchanged. As is clear from FIG. 4, the resonant frequency is originally 1070 MHz when there is nothing between the radiating element and the ground plane, but by inserting the metal block, the resonant frequency is significantly lowered. Furthermore, the metal block moves away from the connection between the radiating element and the ground plane (P becomes smaller)
It can be seen that the resonant frequency decreases accordingly. In this case, the lowest resonant frequency is 820 MHz, and it can be seen that the size is reduced to about 75% compared to the case without the metal block.

In this way, in order to insert circuit components into the air gap of a plate-shaped inverted-F antenna and obtain the same effect as a metal block, large metal parts such as batteries and filters are used as radio equipment parts using stubs. By placing the antenna further away, it is possible to downsize the antenna to the extent that self-resonance occurs.

FIG. 5 shows the radiation pattern of the radio device of this embodiment. (a) shows the radiation pattern, and (b) shows the radio structure. By placing the battery on the side farther from the stub with a radiation plate and base plate measuring 80 x 31 mm, the original 67 mm
It should resonate at 0MHz, but at about 400MHz
It resonated with itself. Its radiation pattern is -10 at maximum
dBd, which is more than 5 dB higher than when using a conventional loop antenna.

That is, as in this embodiment, two conductor plates connected by stubs are used to insert a radio circuit between the conductor plates of the antenna that act as each radiating element and the ground plane, and connect large metal parts such as batteries. By placing the antenna on the side farther from the stub, the resonant frequency of the antenna is lowered and self-resonance occurs, resulting in high gain.

[0013]

[Embodiment 2] FIG. 6 shows a second embodiment of the present invention, in which 1
are radio circuit components, 2 is a battery, 3' is a case made of a material with a high dielectric constant, 4a and b are antenna radiation elements, a conductor plate that acts as a ground plane, 5 is a connection point of the conductor plate, and 6 is a feeder. It's an electric wire. With this configuration, the battery, which is a large metal component, works as part of the antenna, and the dielectric material further reduces the size of the antenna, causing the antenna to self-resonate, eliminating the need for a matching circuit, and increasing the cost. gain is obtained.

[0014] In the first embodiment, if the antenna is not yet miniaturized to the point of self-resonance, the case is made of a material with a high dielectric constant, and the antenna is further miniaturized to achieve self-resonance. In this case as well, high gain can be obtained due to self-resonance as in the first embodiment.

In the first and second embodiments, a battery was considered as the large metal component, but any large radio circuit component may be used, and a filter housed in a shield case or the like may also be considered. Furthermore, in Examples 1 and 2, a plate-shaped inverted F antenna was used as the antenna, but two antennas were connected at appropriate points.
It is sufficient if the antenna has one conductor plate, and the number of connection parts is not limited to one, but may be any number of points.

[0016]

Effects of the Invention As explained above, the present invention provides two conductive plates having a narrow interval compared to the wavelength and connected at one or more places, one of which is used as a ground plate and the other as a radiating element. In a small radio device, the radio circuit is housed between the two conductor plates, and the large metal parts are housed between the two conductor plates. A matching circuit is created by storing the antenna in the space between the two conductor plates on the side far from the connection point of the plates, and further inserting a dielectric between the two conductor plates to make the antenna self-resonate. It is possible to provide a compact wireless device with high gain without the need for it.

[Brief explanation of the drawing]

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

FIG. 2 is a diagram showing a first example of a conventional radio device.

FIG. 3 is a diagram showing a second example of a conventional radio device.

FIG. 4 is a diagram showing the characteristics of the resonant frequency when a metal block is inserted into the air gap of a plate-shaped inverted F antenna.

FIG. 5 is a diagram showing actually measured values of the radiation pattern of Example 1.

FIG. 6 is a diagram showing a second embodiment of the present invention.

[Explanation of symbols]

1 Wireless circuit component 2 Battery 3 Case 3' Case 4a made of a material with high dielectric constant
Conductor plate 4b that operates as a radiating element of the antenna Conductor plate 5 that operates as the ground plane of the antenna Conductor plate connection point 6 Feed line 7 Loop antenna 8 Matching circuit

Claims (2)

[Claims] Claim 1: A small radio device equipped with an antenna having two conductor plates connected at least at one point and having a narrow interval compared to the wavelength, one of which serves as a ground plane and the other serves as a radiating element, At least a part of the circuit components constituting the antenna is arranged between the two conductor plates, and a large metal part of the circuit components is arranged at a position away from the connection point of the two conductor plates, so that the antenna is caused to self-resonate. A small radio device characterized by: [Claim 2] The small radio device according to claim 1,
A small radio device characterized in that a dielectric material is inserted at least partially between two conductor plates.