JPS6220402A - Indoor high frequency antenna system - Google Patents

Abstract

PURPOSE:To obtain the reception state of good capacity with a small-sized antenna by forming a diversity antenna with plural high frequency pickups and detecting the high frequency surface current which is induced in the structure of a building by broadcast waves of a high frequency band. CONSTITUTION:Four high frequency pickups 28 (28-1, 28-2, 28-3, and 28-4) are provided in proper positions in the upper part like a beam part of the structure. Reception signals of broadcasting radio waves obtained by pickups 28 are inputted to a switching circuit 102 by coaxial cables 100-1-100-4. The circuit 102 selects the reception signal of one of pickups 28 and outputs it to a tuner 104. Then, broadcasting waves different in frequency band or broadcasting station are received with a good sensitivity by pickups 28. Thus, the reception state of good capacity is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an indoor high-frequency antenna device, and particularly to an indoor high-frequency antenna device that effectively detects broadcast waves transmitted from a broadcasting station or communication waves transmitted from other stations. This invention relates to an indoor high frequency antenna device that supplies detection signals to various receivers.

[Prior Art] Antenna devices for receiving various broadcast waves, such as broadcast communication waves from radio, television, telephone, etc., using a receiver installed indoors are well known. This type of antenna device is also used for transmitting and receiving, for example, citizen band radio waves, and can receive audio and image signals carried by radio waves in various frequency bands.

Dipole antennas, Yagi antennas, etc. are known as conventional general antenna devices, and dipole antennas are made by arranging two conductive wires of equal length in a straight line and connecting a feeder line to the center, reducing the total length by half. The Yagi antenna has a wavelength of t of the dipole antenna.
This is an antenna that has directivity by attaching a waveguide and reflector to the J antenna.

In addition to the Q In outdoor antenna, there are also indoor antennas, but they have poor reception sensitivity and are extremely obstructive due to the placement of furniture, etc., so they are rarely used today. . Therefore, antennas are installed on the roofs of houses or buildings to ensure good reception of radio waves.

[The problem that the invention aims to solve] ``L Arashi Kogori Danzan However, conventional antennas that are mounted on the roof or rooftops are often installed carelessly, ignoring the appearance of the house or building.'' This caused the problem of extremely damaging the beauty of the building and disturbing the 8m streetscape.

In addition, antennas installed on roofs, etc. are constantly exposed to wind and rain, so they deteriorate quickly due to navigation etc.
On the other hand, since there is a risk of the antenna being knocked down by a typhoon or strong winds, there was a request for an antenna that would not be installed casually protruding from the building.

Furthermore, the high frequency band used for broadcasting radio waves is FM
The problem is that a separate antenna must be installed for each frequency band, and the location of each broadcasting station and surrounding buildings The direction of the incoming radio waves differs depending on the installation position.
There has been a problem in that a single antenna cannot receive multiple broadcast waves with good sensitivity.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems.
The purpose is to effectively detect high-frequency surface currents induced in conductive structures of buildings by broadcast waves, and to efficiently receive multiple broadcast waves with an antenna that does not spoil the aesthetics of the building. The purpose of the present invention is to provide an indoor high-frequency anti-dog device that can be used for indoor use.

[Means and operations for solving the problems] In order to achieve the above object, the present invention provides a plurality of high frequency pickups arranged in a conductive structure forming the skeleton of a building, and a plurality of high frequency pickups. The pickup is characterized by forming a diversity antenna for high frequency band reception. This high frequency pickup detects high frequency surface current induced by broadcast waves and flowing on the surface of the structure.

In recent years, conductive structures such as steel frames, steel pipes, or their accessories, such as braces, have been used as frame units for buildings, and the incoming radio waves generate surface currents in these conductive structures. It is expected that this surface current flows concentratedly at the edges of the structure. Therefore, if the high-frequency surface current at the edge of the structure is effectively detected, good reception of broadcast waves is possible.

In addition, in order to reliably detect high frequency surface currents in the FM frequency band or above, that is, 501412 or above, the high frequency pickup of the present invention reliably detects the high frequency surface current of 501412 or above. ]
(C=speed of light, f=carrier frequency of broadcast wave), and magnetic flux generated by high frequency current can be electromagnetically detected.

If a plurality of such high-frequency pickups are arranged in a structure, broadcast waves from different frequency bands or broadcasting stations can be received with high sensitivity by one of the high-frequency pickups, and multiple high-frequency pickups can be used to receive multiple broadcast waves from different frequency bands or broadcast stations. Broadcast waves can be received with good sensitivity.

[Example] Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a state in which high-frequency pickups are provided on a steel frame rod as a structure forming the frame of a building, and in this embodiment, four high-frequency pickups 28 are provided at the four corners of the steel frame. These four high frequency pickups (
28-1, 28-2゜28-3, 28-4) are provided at an appropriate position on the upper part of the structure, for example on the beam part, as shown in the figure, but they have the best distribution characteristics of high frequency surface current. It is necessary to select the antenna installation position, and first, the process of determining the antenna installation position will be explained based on FIGS. 6 to 8.

FIG. 6 shows a probe P that detects a high frequency surface current flowing through a structure, and this probe P is basically the same as a high frequency pickup to be described later. That is, in order to avoid mixing of radio waves from the outside, a loop coil 12 is fixed inside a case 10 made of a conductor. The frontage 10a is exposed to the outside, and the exposed portion of the loop coil 12 is brought close to the surface of the structure so that the magnetic flux generated from the current on the surface of the structure is transferred to the loop coil 12.
consists of the configuration detected by

A portion of this loop coil 12 is connected to the case 10 by a shorting wire 14, and an output end 16 is connected to a core wire 20 of a coaxial cable 18.

A capacitor 22 is provided in a part of the loop coil 12, which causes the frequency of the loop coil 12 to resonate with the desired frequency to be measured, thereby increasing the pickup efficiency L!
-I am.

By moving the probe P having such a configuration along the surface of the structure and rotating its angle at each measurement point, the surface current distribution and its direction on the surface of the structure are accurately determined.

That is, the output of the probe P is amplified by the high frequency voltage amplifier 24, and the output voltage is measured by the high frequency voltage measuring device 26.

This coil output voltage can be read using the meter support value of the measuring device 26, and the setting position of the high frequency pickup can be determined based on this meter support value.

FIG. 7 shows the deflection angle θ between the high-frequency surface current ■ and the loop coil 12 of the probe P. As shown in the figure, the magnetic flux φ caused by the current ■ interlinks with the loop coil 12, so that the loop coil 12 Generate a detection voltage ■. As shown in FIG. 8, the maximum voltage is obtained when the deflection angle θ is 0, that is, when the surface current l and the loop coil 12 of the probe P are parallel, so it is necessary to rotate the probe P at each measurement point. The direction of the surface current I at which the maximum voltage can be obtained can be determined by .

In this way, the installation position of the high-frequency pickup can be determined, but at the same time, with this probe P, it is also possible to know how far the loop coil 12 can be separated from the edge of the point body. can.

Figure 9 shows the distribution characteristics of 80HIIZ FM broadcast waves, and the surface current value decreases as the distance from the edge of the structure increases, and within 5 dB where good sensitivity can actually be obtained. Considering the current reduction range, it is understood that practically sufficient antenna characteristics can be obtained if the antenna is placed within 4.5 cm from the edge of the structure.

Similar results are obtained for various frequency bodies, and according to computer simulations and various experimental results, the separation distance of the loop antenna 12 is N
1 distance is inversely proportional to the frequency, and from the edge of the structure, 12
x 10'c/f [ml (c = speed of light, f = carrier frequency of broadcast wave)], and the antenna of the modified frequency pickup is set within the above separation distance from the edge of the structure. By doing so, it is possible to obtain a good receiving effect according to each carrier frequency.

For example, at a carrier frequency of 100 Hz, the separation distance depends on the frequency, so according to the above formula, it is sufficient to install the high frequency pickup within 3.6 cm, and as the carrier frequency f increases, the separation distance of the high frequency pickup depends on the frequency. The loop antenna will be installed very close to the edge.

In this embodiment, the high frequency pickup thus installed is attached to a steel beam 30 as shown in FIGS. 2 and 3.

In the figure, the high frequency pickup 28 is a structure H
It is attached to a steel beam 30 of the type, and this steel beam 30 is attached to a column 32 via a connecting steel plate 34,
The pillars 32 and the steel beams 30 are firmly assembled with reinforcements 36 interposed within the quadrilateral steel frame constructed by them. The high-frequency pickup 28 is attached to the lower end of an H-shaped steel beam 30, and its attachment details are shown in FIG. 10.

The high frequency pickup 28 in the embodiment is of an electromagnetic coupling type, and a loop antenna 38 detects magnetic flux generated by high frequency surface current. Then, as shown in FIG. 2, a case 40 having this loop antenna 38 is provided.
is provided with an opening 40a through which a longitudinal piece of the loop antenna 38 is exposed, and the loop antenna 38 is arranged close to the edge of the steel beam 30 in this opening 40a, and the bolt/nut 42 It is fixed to the steel beam 30 by.

Further, an impedance matching circuit 44 is connected to the loop antenna 38, and this impedance matching circuit 44 is connected to a cable connector 45 so as to supply received broadcast waves to the receiver via the cable connector 45. It has become.

Therefore, the magnetic flux generated from the high frequency surface current flowing at the edge of the steel beam 30 is reliably captured by the loop antenna 38 and supplied to the receiver via the impedance matching circuit 44.

Further, the case 40 is configured to shield magnetic flux from the outside so that the current induced in the steel beam 30 is efficiently detected by the high frequency pickup 28.

The case 40 of this high frequency pickup 28 is made of iron.
- It is firmly positioned and fixed to the bone beam 30. For this purpose, L-shaped brackets 46 are provided at both ends of the case 40, and the brackets 46 at both ends are attached to the steel beam a2 by bolts and nuts 1 to 42. It is fixed with screws.

In such a high frequency pickup 28, the loop antenna 38 consists of a single-turn antenna, and the coil is coated with an insulating coating so that it is placed in close contact with the steel beam 30 while being electrically insulated. If the structure is such that it is pressed against the loop antenna 30, the magnetic flux generated from the surface current can be more strongly linked to the loop antenna 38.

In addition, in the embodiment, case 4 of this loop antenna 38
The loop antenna piece exposed from 0 is placed within 4.5 cm from the edge of the steel beam 30, thereby making it possible to
Broadcast waves in the FM band, VHF band, or U)-IF band of 8H2 or higher can be reliably detected by picking up the high-frequency surface current flowing at the edge of the steel beam 30.

As described above, according to the embodiment of the present invention, the loop antenna 38 of the high-frequency pickup 28 is arranged so that its longitudinal direction is along the edge of the steel beam 30, and the high-frequency surface flowing along the edge of the steel beam 30 is By electromagnetically detecting current, it is possible to reliably receive broadcast waves in a high frequency band.

In the present invention, four such high-frequency pickups are provided at the four corners of the steel frame, and the broadcasting signals obtained by each high-frequency pickup 28-1.28-2.28-3.28-4 are Radio wave reception signal is coaxial cable 100-1~
It is input to the switching circuit 102 by 100-4.

This switching circuit 102 switches four high-frequency pickups 28 that constitute diversity reception of one broadcasting radio wave, and these high-frequency pickups 28
Any one of the received signals from -1 to 28-4 is selected and output to the tuner 104. This tuner 104 selects the received signal, and is connected to a high frequency amplifier 1069.
It is constructed with well-known circuits of a local oscillator 108 and a mixer 110.

Then, the received signal tuned by the tuner 104 is amplified by the video intermediate frequency amplifier 112, and the image display circuit 1
14 and audio output circuit 116, respectively. Here, the audio output circuit 116 is connected to the audio separation circuit 118.
．． Audio intermediate frequency amplifier 120. It consists of a well-known configuration of an audio detection circuit 122 and an audio amplifier 124, and separates an audio signal from the signal output from the video intermediate frequency amplifier 112, detects it, and outputs the audio signal from the speaker 126.

The image display circuit 114 of this embodiment also includes a video detection circuit 128. Video amplifier 130. A synchronization circuit 132 connected to the deflection circuit of the cathode ray tube 136 via vertical and horizontal deflection circuit sections. It consists of the well-known arrangement of a chromaticity circuit 134 connected to a grid of cathode ray tubes 136. Then, a video signal is detected by a video detection circuit 128 from the signal outputted via the video intermediate frequency amplifier 112, and after this detected signal is amplified by a video amplifier 130,
grid, a synchronization circuit 132, and a chromaticity circuit 134, respectively, thereby displaying an image of the video signal on a cathode ray tube 136.

Although the present invention can obtain good images and sounds from the broadcasting radio waves received by the image display circuit 114 and the audio output circuit 116, it is possible to obtain good images and sounds from the broadcasting radio waves received by the image display circuit 114 and the audio output circuit 116. High frequency pickup as obtained 28
Diversity reception is performed so that -1 to 28-4 are switched to the optimum one.

That is, the switching circuit 10 that switches the antenna
2 is a switching signal that is sent to the antenna switching circuit 138 when the output of the video detection circuit 128 falls below a certain level.
Then, a switching signal 138a is generated to switch to the antenna with the best reception condition. Note that antenna switching can also be performed using audio detection output.

Also, the antenna switching timing is determined by the vertical synchronization signal 132.
The retrace section of the scanning line can be switched in synchronization with a.

In this way, you can select the high frequency pickup with the best reception condition and always keep it in good condition for the FM band and TV Ul-I.
Broadcasting radio waves such as F band and VHF band are received, and reception with high sensitivity is possible for various directions of arrival of radio waves.

In the above embodiment, the high frequency pickup 28 is attached to a steel beam of a steel frame, but steel pipe columns may also be used as the structure of a building, and FIGS. 4 and 5 show other embodiments of attaching the high frequency pickup. As shown in FIG.
8' can be provided. In the figure, the high frequency pickup 28- is mounted above the ridge corner of the steel pipe column 48 forming the structure of the building, and is mounted at the open end 5.
A loop antenna 38- is arranged along 0. Therefore, the case 40' on the frontage end 50 side has an opening 40'a.
A loop antenna 38- is formed with an insulating coating.
I try to keep close contact with them. And in this example,
In both parts, 12 x 10-”c, # [m] from the other side where the high-frequency pickup 28' is not attached.
The loop antenna 38' is arranged at a distance of Ω, thereby making it possible to efficiently pick up the surface current flowing concentratedly at the ridge corner of the steel pipe column 48.

[Effects of the Invention] As explained above, according to the present invention, a diversity antenna is configured with a plurality of high-frequency pickups, and high-frequency surface currents induced in the structure of a building by broadcast waves in a high-frequency band are efficiently absorbed. Since it has been designed to detect various broadcast waves well, it is possible to obtain high-performance reception conditions with a small antenna device without having to erect a dipole antenna or other antenna on the roof or the like as in the past. .

In addition, it is possible to ensure a highly sensitive reception condition for various directions of radio waves, and to select a highly sensitive high-frequency pickup in accordance with changes in building erection conditions in the environment, while receiving good broadcast waves, etc. Can receive data.

As a result, the antenna that is provided protruding outdoors can be removed, and the beauty of the building, such as a house or a building, will not be spoiled.

Furthermore, since the antenna device of the present invention does not need to be installed protruding outdoors, it is possible to obtain an extremely durable anti-j device that does not rust due to rain, wind, etc., and is extremely safe in terms of safety. It can be used as a built-in device.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a preferred embodiment of the indoor high-frequency antenna device according to the present invention, FIG. 2 is a perspective view showing an example of mounting a high-frequency pickup constituting the antenna device of the present invention, and FIG. Figure 2 is a cross-sectional view of the main parts showing the installation of the high-frequency pickup (=I), Figure 4 is an explanatory diagram showing another example of installing the high-frequency pickup, and Figure 5 is the installation of the high-frequency pickup shown in Figure 3. 6 is an explanatory diagram of a probe and its processing circuit for determining the distribution of surface current of a structure using a probe similar to the high-frequency pickup used in the present invention; FIG. An explanatory diagram that does not show the electromagnetic coupling state between the surface current I and the pickup loop antenna. Figure 8 is an explanatory diagram showing the directivity characteristics of the loop antenna in Figure 7. Figure 9 is a diagram showing the high-frequency surface current near the edge of the structure. It is a characteristic diagram showing the distribution. 28-1.28-2.28-3.28-4... High frequency pickup 30... Steel beam 38 as a structure...
Loop antenna 48... m-tube column 104 as a structure... tuner 102... switching circuit 114... image display circuit 116... audio output circuit

Claims (2)

[Claims] (1) A plurality of high-frequency pickups are provided on a conductive structure that forms the framework of a building and detect high-frequency surface currents induced by broadcast waves on the surface of this structure, and the plurality of pickups generate high-frequency waves. An indoor high frequency antenna device characterized by forming a diversity antenna for band reception. (2) In the antenna device according to claim (1), the high frequency pickup includes a loop antenna, and the loop antenna extends from the edge of the structure by 12×10^-^.
An indoor high-frequency antenna device characterized in that it is installed at a distance within c/f [m] (c = speed of light, f = carrier frequency of broadcast waves).