JPS6224705A - Antenna - Google Patents

Abstract

PURPOSE:To increase the gain and to eliminate the directivity by providing a ferrite antenna formed by winding the 1st winding to a ferrite rod, the 2nd winding wound while the earth end of the 1st winding is used as the turn start and a rod implanted vertically to the ferrite rod at the end turn of the 2nd winding. CONSTITUTION:The ferrite antenna 1 formed by winding the 1st winding 3 to the ferrite rod 2, the 2nd winding 5 wound while the earth side of the 1st winding 2 is used as the start turn and the rod 4 implanted vertically to the ferrite rod 2 at the end turn of the 2nd winding 5 are provided. In the title antenna system, the strong directivity of the ferrite antenna is cancelled by the rod implanted vertically to the ferrite rod, the effect of a human body is made not susceptible and stable reception is attained. Further, the gain is increase than the antenna gain of the ferrite antenna or the rod antenna and the reception sensitivity is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to an antenna used for a cordless intercom or the like.

[Background Art 1] Conventionally, a ferrite antenna in which a wire is wound around a ferrite rod is sometimes used in cordless intercoms and the like because it is effective in reducing the size of the device and is convenient in that the antenna can be built into the He.

However, this type of ferrite antenna has low antenna gain and strong directivity, so although it is suitable for short-range wireless communication indoors etc. from the standpoint of miniaturizing the antenna,
There were problems with gain and directivity in long-distance communications and outdoor use.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its object is to provide an antenna that can increase the gain of the antenna and eliminate directivity.

DISCLOSURE OF THE INVENTION (Example 1) FIG. 1 is a diagram showing an example of the present invention. A ferrite antenna 1 in which a first winding #13 is wound around a ferrite rod 2, a second winding 5 wound starting from the ground side of the first winding 2, and a second winding 5 wound around the first winding #13. A ferrite rod 2 and a vertically erected rod 4 are provided at the end of the winding 5. More specifically, the ferrite rod 2 has a cylindrical shape with a diameter of 15 am and a length of 5011II6, as shown in FIG. and the other end is grounded. Further, a variable capacitor C for tuning adjustment is connected to both ends of the first winding 3.

Experimental results of this example with the above-described configuration will be shown below.

This experiment is the result of an experiment using a 60 MHz band ferrite antenna as an example. Table 1 shows that the second winding 5 is wound from the ground side of the first winding #[3 in the same direction as the first winding #i3, and the length of the rod 4 is The gain and directivity of a pair of λ/2 antennas were measured when the length α and the number of turns T were changed.

The second number of turns, 5, is a 0.6φ enamelled wire that is tightly wound. The gain represents the antenna loss and is expressed in decibels (dB), and the directivity represents the value obtained by subtracting the minimum value from the maximum value of the electric field strength. still,
Although a prismatic ferrite rod 2 is used in the experiment, there is no significant difference in actual measurements.

Table 1 Here, the values in the upper row are the antenna gain, and the values in the lower row are the values indicating the directivity.

In Table 2, the second winding 5 is wound with the live wire side as the starting end as shown in FIG. 4, and the other conditions are the same as in Table 1.

From the results shown in Table 2 and above, it was found that the optimum number of turns for W42 of 5 turns is 3 turns. Therefore, as shown in Table 3, the number of turns of the second winding 5 is fixed to 3 turns, the length of the rod 4 is changed, and the starting end of the second number of turns 5 is set to 7-turns of the first number of turns 3. From the experiments shown in Table 3 and above, the directivity in the horizontal plane can be improved by setting the rod 4 perpendicularly to the ferrite rod 2, with the second winding 5 running in the opposite direction to the first winding 3. I know it will disappear. It can also be seen that the antenna gain is larger than when using the ferrite antenna 1 alone or the rod antenna alone. Furthermore, it was found that the second winding 5 should be wound from the ground side of the first winding 3, and that the length of the rod 4 should be 30 cm.

(Embodiment 2) FIG. 6 is a diagram showing another embodiment of the present invention. In this embodiment, the rod 4 was always attached in the first embodiment, but it is not necessary to always put the rod 4 upright. This focuses on the fact that there are cases where there is no such thing. In other words, for short-range wireless communication indoors or the like, it is more compact and easier to handle without the rod 4. Therefore, as shown in FIG. 6, the second winding 115 wound around the ferrite rod 2 of the ferrite antenna 1 housed in the case 7 is pulled out and the rod 4
The rod 4 is made removable at this connection part 6. In this case, under normal conditions, the rod 4 can be removed and the mackerel can be moved as needed (for example, between the main house and the outbuildings). It is a good idea to attach a port 4 (for example, when communicating with other people).

(Embodiment 3) In the above embodiment, the second winding #i3 is wound around the 7-elite antenna 1, and the rod 4 is further wound at the end of the second winding 5.
This is to eliminate the directivity of the ferrite antenna 1 and increase the antenna gain, but if you simply want to eliminate the directivity of the ferrite antenna 1, you can do it as follows.Normally, the ferrite antenna 1 is As shown in Fig. 7, the ferrite antenna 1 has a figure-8-shaped directivity characteristic in the horizontal plane, and the directivity in the central axis direction is weak. It is placed on a shield case 8 which has a built-in circuit and has the same potential as the ground wire of the ferrite antenna 1. Then, the shield case 8 itself becomes a part of the antenna, and horizontal directivity can be eliminated. As a result of studying the placement of the ferrite antenna 1 in a transmitter/receiver equipped with two ferrite antennas 1 for transmitting and receiving, as shown in Figure #S9, a 7-piece light antenna for receiving is placed on the shield case 8, and a ferrite antenna for transmitting is placed on the shield case 8. Compared to the case where the ferrite antenna 1b is placed next to the shield case 8, the transmitting ferrite antenna 1b is placed on the shield case 8 and the receiving ferrite antenna 1a is placed next to the shield case 8, as shown in FIG. It is clear that it is better to
(Tsuru) and antenna gain (dB) were measured.

'Table 4 shows the results. Here, in the table (
a) is the measured value with the rod 4 standing vertically from the side of the shield case 8 as shown in Fig. 11, and (b)
) is the measured value when the folded ferrite antenna 1 is once vertically erected at the axial position along the upper surface of the shield case 8 as shown in FIG. Note that the values listed at the bottom are values indicating directivity.

From Table 4 and above, it can be seen that the transmission strength shown in (b) is strong and the directivity is also good. The length of the rod 4 is 30 cm, and the second winding llA3 is wound with three turns around the receiving ferrite antenna 1a as described above, and the transmitting ferrite antenna 1b is connected to the rod 4. I haven't.

(Embodiment 4) Further, a case will be described in which the antenna described in Embodiment 1 is shared for transmission and reception. In this case, as shown in FIG. 13, a transmitting circuit is connected to the rod 4 via a bandpass filter 9, and a receiving circuit is connected to the first winding 3 of the ferrite antenna 1 via a bandpass filter 10. In this way, the directivity can be made weaker than in the case of using a rod antenna, so that it is possible to prevent a decrease in the gain of the receiving antenna due to the influence of the human body or the like.

[Effect of the Invention 1] As described above, the present invention provides a ferrite antenna in which a first winding is wound around a 7-elite rod, and a second winding wound with the ground side of the first winding as the starting end. Since the second winding has a rod that stands perpendicular to the ferrite rod at the end of the second winding, the directivity of the ferrite antenna, which has strong directivity, can be canceled out by the rod that stands perpendicular to the ferrite rod. This makes it less susceptible to the effects of the human body, allowing stable reception, and the first 8#! By providing a second winding wound starting from the 7th side of the winding, and a rod standing perpendicular to the ferrite rod at the end of the second winding,
The gain can be increased compared to the antenna gain of a ferrite antenna or a rod antenna, which has the effect of improving receiving sensitivity.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic circuit configuration diagram of an embodiment of the present invention, Fig. 2 is a perspective view showing the shape of the main parts of the same, and Figs. 3 to 5 show antenna gain and directivity. FIG. 6 is a schematic configuration diagram showing another embodiment of the present invention, FIG. 7 is an explanatory diagram showing the directivity of a ferrite antenna,
FIG. 8 is a schematic configuration diagram showing still another embodiment of the present invention,
Figures 9 and 10 are configuration diagrams showing the antenna arrangement when two ferrite antennas are used for transmission and reception, #l
FIG. 111 and FIG. 12 are explanatory diagrams showing experimental conditions when a rod is used, and FIG. 13 is a schematic circuit configuration diagram showing still another embodiment of the present invention. 1 is the ferrite antenna, 2 is the 7-elite rod, 3 is the first
, 4 is the rod, and 5 is the second winding. Figure 11 Figure 1N7 Figure taB Figure Army Figure 9! 109- Figure 12 Figure 13 Procedural amendment (voluntary) September 7, 1985 Patent Application No. 164337 of 1985 2, Title of invention Antenna 3, Relationship with the person making the amendment Patent applicant address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (58
3) Matsushita Electric Works Co., Ltd. Representative Fujii 1 Husband 4 Agent postal code 530 Address 1-12-17-5 Umeda, Kita-ku, Osaka City Date of amendment order Vol. 6 Number of inventions increased by amendment None [11 The specification of the present application is amended as shown in the attached sheet. [21 Figures 9 and 10 in the attached drawings are corrected as shown in the attached sheet, and Figures 11 to 13 are deleted. Agent Patent Attorney Ishi 1) Long 7 Amended Specification 1, Title of Invention Antenna 2, Claims (1) A ferrite antenna in which a first winding is wound around a ferrite rod, and An antenna comprising a second winding wound starting from the ground side, and a rod standing perpendicular to a ferrite rod at the end of the vJ2 winding. (2) The antenna according to claim 1, wherein the rod is removable. 3. Detailed Description of the Invention [Technical Field 1] The present invention relates to an antenna used for a cordless intercom or the like. BACKGROUND ART 1 Conventionally, a ferrite antenna in which a wire is wound around a ferrite rod has been used in cordless intercoms and the like because it is effective in reducing the size of the device and is convenient in that the antenna can be built into the device. However, this type of ferrite antenna has low antenna gain and strong directivity, so although it is suitable for short-range wireless communication indoors etc. from the standpoint of miniaturizing the antenna,
There were problems with gain and directivity in long-distance communications and outdoor use. [Object of the Invention] The present invention has been made in view of the above-mentioned points, and its object is to provide an antenna that can increase the gain of the antenna and eliminate directivity. [Disclosure of the Invention 1 (Embodiment 1) Fig. 1 is a diagram showing an embodiment of the present invention, in which a ferrite antenna 1 in which a first winding 3 is wound around a ferrite rod 2, and a ferrite antenna 1 in which a first winding 3 is wound around a ferrite rod 2, and It is equipped with a second winding #[5 wound starting from the ground side of the wire 2, a 7-elite rod 2 at the end of the second winding 5, and a rod 4 standing vertically. . More specifically, the ferrite rod 2 has a cylindrical shape with a diameter of 15 mm and a length of 50 m, as shown in FIG. It is connected to the input lighthouse, and the other end is grounded. Further, a variable capacitor C for tuning adjustment is provided at both ends of the first winding 3.
is connected. Experimental results of this example with the above-described configuration will be shown below. This experiment is the result of an experiment using a 60 MHz band ferrite antenna as an example. Table 1 shows the length of the rod 4 by winding the second winding 5 from the ground side of the first winding 3 in the same direction as the first winding 3. α and number of turns T
The gain and directivity of the λ/2 antenna were measured when the λ/2 antenna was changed. The second number of turns, 5, is a 0.6φ enamelled wire that is tightly wound. The gain indicates the antenna gain, and the unit is decibel (dB). Further, the directivity is the value obtained by subtracting the minimum value from the maximum value of the electric field strength. still,
Although a prismatic ferrite rod 2 is used in the experiment, there is no significant difference in actual measurements. Table 1 Unit Q: [cIll Here, the value in the upper row is the antenna gain, and the value in the lower row is the value indicating the directivity. In Table 2, the second winding 5 is wound with the live wire side as the starting end as shown in FIG. 4, and the other conditions are the same as in Table 1. Table 2 Unit α: [eml From the above results, it was found that the optimal number of turns for the second number of turns 5 is 3 turns. Therefore, as shown in Table 3, the number of turns of the second winding 5 is fixed to 3 turns, and the rod 4
, change the length of the second winding 5, make the starting end of the second winding 5 the ground side and live wire side of the first winding 3, and connect the second winding 5 in the opposite direction to the first winding 3. 0. : [cm1 From the above experiments, it is clear that by standing the rod 4 perpendicularly to the 7-elite rod 2, the directivity in the horizontal plane disappears. It can also be seen that the antenna gain is thicker than when using the ferrite antenna 1 alone or the rod antenna alone.Furthermore, the second winding 5 is wound from the ground side of the first winding 1i3, and the length of the rod 4 is increased. The results showed that a height of 30 cm is good. (Example 2) Fig. 6 is a diagram showing another example of the present invention, and this example is different from Example 1 in that the rod 4 is always attached. However, there are cases where it is not necessary to always stand up this rod 4.g
The focus was on In other words, for short-range wireless communication indoors or the like, it is more compact and easier to handle without the rod 4. Therefore, as shown in FIG. 6, the second winding 5 wound around the ferrite rod 2 of the ferrite antenna 1 housed in the case 7 is pulled out, and the opening is placed on the surface of the case 7. Do 4
, and the rod 4 is made removable at this connection g6. In this case, the rod 4 is removed under normal conditions, and when necessary (for example, communication between the main building and the outbuildings). It is better to attach the rod 4. (Embodiment 3) In the above embodiment, the second winding 3 is wound around the ferrite antenna 1, and the rod 4 is erected at the end of the second winding 5 to eliminate the directivity of the ferrite antenna 1. This is to increase the antenna gain, but if you simply want to eliminate the directivity of the ferrite antenna 1, you can do it as follows.1 Normally, the ferrite antenna 1 has a figure-8 shape in the horizontal plane as shown in Figure 7. The ferrite antenna 1 having such characteristics is placed in a shield case 8 that has a built-in transmitting circuit or a receiving circuit and has the same potential as the ground wire of the ferrite antenna 1. Then, the shield case 8 itself becomes a part of the antenna, and the horizontal directivity can be eliminated.Based on this, the ferrite case 8 in a transmitter/receiver equipped with two transmitting/receiving ferrite antennas 1. As a result of considering the arrangement of the antenna 1, as shown in FIG. 9, the ferrite antenna 1a for reception is arranged on the shield case 8, and the ferrite antenna 1b for transmission is arranged under the shield case 8. (Example 4) ) Furthermore, a case will be described in which the antenna described in Embodiment 1 is shared for transmission and reception. In this case, as shown in FIG. A receiving circuit is connected to the winding 3 of the antenna via a bandpass filter 10.In this way, the directivity can be made weaker than when using a rod antenna, so that the gain of the receiving antenna due to the influence of the human body, etc. [Effects of the Invention] As described above, the present invention provides a ferrite antenna in which a first winding is wound around a 7-item rod, and a ferrite antenna in which a first winding is wound around a 7-item rod; Since it is equipped with a second winding wound starting from the ground side and a rod erected perpendicularly to the ferrite rod at the end of the second winding, it is possible to use a 7-elite antenna with strong directivity. The directivity can be canceled by using a rod set perpendicular to the ferrite rod, making it less susceptible to the effects of the human body, etc., making stable reception possible.
. a second winding wound with
By providing the elite rod and the vertically erected rod, the antenna gain can be increased compared to that of a ferrite antenna or a rod antenna, and the receiving sensitivity is improved. 4. Brief description of the drawings Fig. 1 is a schematic circuit configuration diagram of an embodiment of the present invention, Fig. 2 is a perspective view showing the shape of the main parts of the same, and Figs. 3 to 5 show the antenna gain and directivity. FIG. 6 is a schematic configuration diagram showing another embodiment of the present invention, FIG. 7 is an explanatory diagram showing the directivity of a ferrite antenna,
Figure 8 is a schematic configuration diagram showing still another embodiment of the present invention;
FIG. 9 is a block diagram showing the antenna arrangement when two ferrite antennas are used for transmission and reception, and FIG. 10 is a schematic circuit block diagram showing still another embodiment of the present invention. 1 is the ferrite antenna, 2 is the ferrite rod, 3 is the first
, 4 is the rod, and 5 is the second winding.

Claims (2)

[Claims] (1) A ferrite antenna in which a first winding is wound around a ferrite rod, a second winding wound starting from the ground side of the first winding, and a terminal end of the second winding. An antenna consisting of a ferrite rod and a vertically erected rod. (2) The antenna according to claim 1, wherein the rod is removable.