JPH1188748A - Wireless antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless antenna device which prevents interference and a damage owing to an obstacle and which can secure high antenna gain. SOLUTION: A plane antenna array 1 is fixed to a reception device 2 through a connector 3 by making the array 1 face the front of a video camera 4. The plane antenna array 1 is fitted to the video camera 4. Thus, the height of the antenna above the video camera 4 is suppressed and the directivity of the plane antenna 1 is made to face the front of the video camera 4. Thus, the directivity gain of the antenna is secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wireless microphone device and a wireless antenna device of a wireless receiver provided in a video camera.

[0002]

2. Description of the Related Art Conventionally, an antenna configuration of a wireless microphone receiving device connected to a video camera and receiving a transmission signal from a wireless microphone device is, for example, as follows.
An inverted antenna pole as disclosed in Japanese Utility Model Laid-Open Publication No. 62-53867 has been generally used.

As another conventional example, a configuration in which a monopole antenna or a sleeve antenna portion as shown in FIG. 7 is fixed to an upper portion of a video camera has been used. That is, in FIG. 7, reference numeral 2 denotes a receiving device for demodulating a received audio signal, reference numeral 4 denotes a video camera for photographing a subject, and reference numeral 5 denotes a wireless microphone transmitter fixed to the upper portion of the receiving device 2 and carried by the subject. Reference numeral 3 denotes a connector for connecting the sleeve antenna unit 5 to the receiving device 2. In general,
In a wireless antenna of this type of wireless microphone device, an 800 MHz band (wavelength: about 380 mm) is used. Usually, the height of a sleeve antenna portion 5 protruding above the video camera 4 is a half wavelength. (About 190 mm).

The video camera 4 is a portable imaging and recording device. In general, a photographer carries his / her shoulder on his / her shoulder and faces the subject to take a picture. The receiving device 2 is a wireless receiving device built in the video camera 4, and generally receives radio waves from a wireless microphone transmitter carried by a subject such as a person and inputs a demodulated audio signal to the video camera 4. . The video camera 4 records an audio signal input from the receiving device 2 together with an image. Sleeve antenna part 5
Is electrically connected to the receiving device 2 via the connector section 3 and is mechanically fixed.

Also, since the directivity in the horizontal plane of the sleeve antenna is omnidirectional, in this conventional example, even though the wireless microphone transmitter is always in front of the video camera 4, the directivity of the antenna of the receiving device is not changed. Sex will be directed in all directions. In this case, the gain of the sleeve antenna is generally about 2.1 dBi.

As a built-in antenna of a conventional wireless microphone transmitter, for example, a built-in antenna in which a monopole antenna or a dipole antenna is disposed inside a wireless microphone housing has been used. As another example of an antenna with a built-in wireless microphone, FIG.
The inverted L disposed inside a wireless microphone housing (disclosed in Japanese Patent Laid-Open No. 9-98494) as shown in FIG.
An antenna composed of an antenna is known.

That is, in FIG. 8, a lead wire 4 is connected to the antenna element 1, and a power supply connector 5 is connected to a predetermined position of the printed circuit board 2.
An inverted L-shaped antenna structure is configured by arranging the antenna element 1 and the printed board 2 in parallel. Further, the parasitic element 3 for impedance matching is disposed so as to face the antenna element 1, and the distance 6 between the antenna element 1 and the parasitic element 3 for impedance matching is changed so that the impedance matching is optimized. I try to make it.

[0008]

Among the wireless antenna devices according to the prior art as described above, the configuration of the wireless antenna device of the wireless microphone receiving device connected to the video camera is described below. Since the height of the image is relatively long at about a half wavelength (approximately 190 mm), there is a problem in that it is likely to come into contact with an obstacle during the photographing operation and there are many failures due to breakage.

Further, in the configuration of the conventional wireless antenna device used for the above-mentioned video camera, since the directivity of the wireless antenna is almost non-directional in a horizontal plane, generally, the direction in which the video camera is directed. There is a problem that it is not possible to increase the antenna gain in the forward direction of the video camera which is the direction of the photographing target or the subject of a human or the like.

[0010] Among the conventional wireless antenna devices as described above, the wireless antenna device built in the wireless microphone transmitter is affected by the proximity effect of the hand depending on the position of the hand holding the wireless microphone with the hand. There has been a problem that the degree of deterioration of the gain changes greatly. For example, when a wireless microphone having a wireless antenna disposed at the bottom is grasped by hand, the gain of the wireless antenna is largely deteriorated, and generally about 10 to 15 dB is generated. On the other hand, when the user grips the upper part of the wireless microphone, that is, the vicinity of the microphone without the wireless antenna, the wireless antenna gain hardly deteriorates.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. The height of a wireless antenna protruding above a video camera is reduced to prevent breakage, and the directivity of the wireless antenna is reduced. It is an object of the present invention to provide a wireless antenna device of a wireless receiving device to be mounted on a video camera that secures a high antenna gain by pointing forward.

Another object of the present invention is to provide a wireless microphone device (wireless microphone transmitter) provided in a wireless microphone device (wireless microphone transmitter) capable of securing a high antenna gain regardless of the position of the wireless microphone device held by a hand. Aim.

[0013]

According to the present invention, there is provided a wireless antenna device of a wireless receiver provided in a video camera according to the present invention, wherein one or more planar antennas constitute a planar antenna array on an upper portion of the video camera and are arranged toward a subject. It is something to do. The present invention uses a planar antenna to reduce the height of a wireless antenna protruding from the top of a video camera to prevent breakage, and arrange the planar antenna toward a subject to change the directivity of the wireless antenna to a video. By directing the camera in front of the camera, a wireless antenna device that can ensure a high antenna gain can be obtained.

A wireless antenna device incorporated in a wireless microphone transmitter according to the present invention includes a wireless first antenna disposed below the wireless microphone transmitter, and a wireless second antenna disposed above the wireless microphone transmitter. , The first antenna and the second
By detecting the reflection component of the high-frequency transmission signal from the antenna,
The wireless antenna having the smaller reflection component is automatically selected, switched, and transmitted. The present invention automatically selects and switches a wireless antenna (first antenna or second antenna) that is not gripped by hand, regardless of where the wireless microphone transmitter is gripped by hand. A wireless antenna device for a wireless microphone transmitter that can ensure a gain is obtained.

A wireless antenna device incorporated in a wireless microphone transmitter according to the present invention has a wireless first antenna arranged below the wireless microphone transmitter and a wireless second antenna arranged above the wireless microphone transmitter. First, an antenna is automatically selected and switched so that a high-frequency transmission signal is transmitted from the first antenna, and if there is a reflected component from the first antenna, is transmitted to the second antenna for transmission. It was done. The present invention automatically selects and switches a wireless antenna (first antenna or second antenna) that is not gripped by hand, regardless of where the wireless microphone transmitter is gripped by hand. A wireless antenna device for a wireless microphone transmitter that can ensure a gain is obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a planar antenna unit, a receiving device to which the planar antenna unit is electrically connected, and a video camera to which the receiving device is fixed. The directivity formed by the planar antenna section is directed to the front of the video camera. The height of the wireless antenna protruding above the video camera is reduced to prevent breakage, and the directivity of the wireless antenna is reduced. By directing the characteristics in front of the video camera, a high antenna gain can be secured.

According to a second aspect of the present invention, the flat antenna section is configured as a flat antenna array by a plurality of flat antennas, and the antenna directivity gain in the forward direction of the video camera is reduced. It has the effect of making it even higher. The invention according to claim 3 of the present invention is such that the flat antenna unit is mounted on the front part of the video camera, and there is no interference such as a handle or a photographer's head in the direction of the subject. This has the effect that a higher antenna gain can be ensured.

According to a fourth aspect of the present invention, there is provided the first antenna disposed below the wireless microphone,
A second antenna disposed in the vicinity of the microphone unit at a predetermined distance from the first antenna, a transmission circuit that processes a voice transmission signal from the microphone unit and outputs a high-frequency transmission signal, A high-frequency signal switching circuit for switching a high-frequency transmission signal to one of a first antenna and a second antenna; and a high-frequency signal transmitted from the first antenna and the second antenna inserted between the high-frequency signal switching circuit and the transmission circuit. A directional coupler for detecting a reflection component of a signal; and the high-frequency signal switching so as to connect a high-frequency transmission signal from the transmission circuit to an antenna having a smaller reflection component upon receiving a detection result of the reflection component by the directional coupler. And a detection control unit for switching a circuit, wherein the detection control unit reduces reflection components from the first antenna and the second antenna. And the Select square antenna those to automatically switch sends to the high frequency transmission signal to the antenna having the smaller reflection component from the transmission circuit,
This has the effect that a high antenna gain can be ensured regardless of the position of the wireless microphone device held by the hand.

According to a fifth aspect of the present invention, there is provided the first antenna disposed below the wireless microphone,
A second antenna disposed near the microphone unit at a predetermined distance from the first antenna, a transmission circuit that processes and outputs a voice transmission signal from the microphone unit, and a high-frequency transmission signal from the transmission circuit. A circulator for transmitting to one antenna and transmitting a reflected signal from the first antenna to the second antenna; transmitting and transmitting a high-frequency transmission signal from the transmitting circuit to the first antenna; If there is, an antenna to be automatically transmitted is selected so as to be transmitted to the second antenna via the circulator and transmitted. This simplifies the configuration of the antenna selection circuit and reduces the size of the entire device.
This has the effect that a high antenna gain can be ensured regardless of the position of the wireless microphone device held by the hand.

According to a sixth aspect of the present invention, the first antenna is constituted by a helical antenna, and the second antenna is constituted by a loop antenna. This has the effect that a space-saving built-in antenna adapted to the above can be configured.

Hereinafter, based on the attached drawings and FIGS. 1 to 6,
An embodiment of the present invention will be described in detail. FIG. 1 is a basic conceptual diagram of a video camera equipped with a wireless antenna device according to a first embodiment of the present invention, and FIG.
FIG. 3 is a basic conceptual diagram of a wireless antenna device provided in a video camera according to the embodiment of the present invention, FIG. 3 is an explanatory diagram of the operation of the wireless antenna device according to the second embodiment of the present invention, and FIG. Basic conceptual diagram of a video camera equipped with a wireless antenna device in the form of
FIGS. 5A and 5B are diagrams illustrating a configuration of a wireless microphone transmitter according to a fourth embodiment of the present invention. FIG. 5A illustrates a configuration of a wireless antenna device incorporated in the wireless microphone transmitter, and FIG. FIG. 6C shows a state in which the lower part of the microphone is held by hand, FIG. 6C shows a state in which the upper part of the wireless microphone is held by hand, FIG.
FIG. 14 is a diagram illustrating a configuration of a wireless antenna device built in a wireless microphone transmitter according to a fifth embodiment of the present invention.

(First Embodiment) First, a configuration of a wireless antenna device provided in a video camera according to a first embodiment of the present invention will be described with reference to FIG. In FIG. 1, reference numeral 2 denotes a receiving device for demodulating a received audio signal, reference numeral 4 denotes a video camera for photographing a subject, and reference numeral 1 denotes a wireless microphone transmitter 17 fixed to an upper portion of the receiving device 2 and carried by the subject. 5) A flat antenna section for receiving the radio wave from 3), and 3 a connector section for connecting the flat antenna section 1 to the receiving device 2.

Next, the operation of the wireless antenna device provided in the video camera according to the present embodiment will be described with reference to FIG. The video camera 4 is a portable imaging and recording device. In general, a photographer carries an image on a shoulder and faces the subject with the body. The receiving device 2 is a wireless receiving device built in the video camera 4, and generally receives a radio wave from a wireless microphone transmitter 17 carried by a subject such as a person, and outputs a demodulated audio signal to the video camera 4. To enter. The video camera 4 includes the receiving device 2
The audio signal input from the device is recorded together with the image. The planar antenna unit 1 is electrically connected to the receiving device 2 via the connector unit 3 and is mechanically fixed by the connector unit 3.

The flat antenna section 1 is disposed in front of the video camera 4 so that the antenna element surface of the flat antenna section 1 faces directly. Generally, the flat antenna section 1 is a plate-shaped inverted-F antenna formed on a dielectric substrate. Be composed. In a plate-shaped inverted-F antenna formed on a dielectric substrate, the perimeter of the antenna element is λg
It is known that resonance occurs at / 2 (λg is the wavelength on the dielectric substrate). For example, when the dielectric constant of the dielectric substrate is selected to be about 3.6 in the 800 MHz band, the length of one side of the antenna element, that is, the height protruding above the video camera 4 is about 24 mm.

Further, since the antenna element (plate-shaped inverted F antenna) of the planar antenna unit 1 is arranged so as to face in front of the video camera 4, the directivity of the planar antenna is directed in front of the video camera 4. Will be. Since the video camera 4 is always pointed at the subject (person, etc.), the directivity of the planar antenna can be directed toward the wireless microphone transmitter 17 carried by the subject (person, etc.). In this case, the directional gain in the maximum gain direction of the planar antenna can generally obtain about 3 to 4 dBi.

As described above, since the directivity in the horizontal plane of the sleeve antenna 5 in the conventional example is omnidirectional,
Although the wireless microphone transmitter 17 is always in front of the video camera 4, the directivity of the sleeve antenna 5 of the receiving device 2 is directed in all directions. In this case, the gain of the sleeve antenna 5 is generally about 2.1 dBi.

As described above, according to the first embodiment of the present invention, the height of the planar antenna 1 projecting above the video camera is about one seventh of the height of the sleeve antenna 5 in the conventional example. Therefore, a problem of interference with an obstacle can be avoided. Further, since the antenna directivity of the receiving device 2 connected to the video camera 4 can always be directed to the direction of the wireless microphone transmitter 17, the directivity gain is about 3 to 4 dBi.
It is possible to obtain a directional gain considerably higher than about 2.1 dBi in the conventional example.

(Second Embodiment) Hereinafter, a configuration of a wireless antenna device provided in a video camera according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 2, reference numeral 31 denotes a plurality of planar antenna elements 8a to 8d.
And a flat antenna unit for receiving a radio wave from the wireless microphone transmitter 17 (FIG. 5) carried by the subject and fixed to the upper part of the receiving device 2, and a plurality of planes 8 a to 8 d constituting the flat antenna unit 31. The antenna element 6 is a dielectric substrate on the surface of which a plurality of planar antenna elements 8a to 8d are formed by etching, plating, attaching, or other means.

Reference numeral 7 denotes a ground plate on which the dielectric substrate 6 is mounted and which serves as a ground for the planar antenna elements 8a to 8d, and 9a to 9d denote planar antenna elements 8a to 8d.
d, through-holes serving as ground contacts for the ground plate 7, 10 a and 10 b are power dividers for synthesizing the reception signals from the planar antenna elements 8 a to 8 d and outputting them to the receiving device 2, 11 a and 11 b are planes A connector for connecting the antenna unit 31 to the receiving device 2. Note that the video camera 4 and the receiving device 2 are the same as those shown in FIG.

Next, the operation of the wireless antenna device provided in the video camera according to the second embodiment will be described with reference to FIG. In FIG. 3, the dielectric substrate 6
Is generally composed of a dielectric substrate having a thickness of about 5 mm to 8 mm and a relative dielectric constant of about 2 to 4 (however,
Any other size). The dielectric substrate 6 is mounted on a ground plate 7, and the ground plate 7 operates as a ground plane for the planar antenna elements 8 a to 8 d formed on the dielectric substrate 6. The ground plate 7 is connected to the ground side of the connector portions 11a and 11b, and operates as a ground plane for the entire flat antenna portion 31. The planar antenna elements 8a to 8d each have a plate-shaped inverted F
Make up the antenna. The through holes 9a to 9d
Each of the planar antenna elements 8a to 8d operates as a ground contact of a plate-shaped inverted-F antenna.

The power distributors 10a and 10b are formed on the dielectric substrate 6 by microstrip lines. The received signals from the planar antenna elements 8a and 8b are combined by the power distributor 10a to form a connector 11a
It is led to. The received signals from the planar antenna elements 8c and 8d are combined by the power distributor 10b and guided to the connector 11a. As described above, the planar antenna element 8
a and 8b and the planar antenna elements 8c and 8d constitute two sets of antenna arrays. Planar antenna elements 8a and 8
b, 8c and 8d to form an antenna array, so that each planar antenna element 8a, 8b and 8c
And 8d, and a high directivity gain can be obtained in the front direction.

In this case, generally, about 5 in the maximum gain direction.
A directivity gain of about 6 dBi can be obtained.
Further, a space diversity antenna is formed by forming two sets (8a and 8b, 8c and 8d) of an antenna array. Here, the height of the planar antenna section 31 in the 800 MHz band is determined by the planar antenna elements 8a to 8a.
d (about 24 mm) and the power distributor 10a
The length can be made substantially equal to the sum of the length (about 15 mm) and the length (about 15 mm), and can be suppressed to about 40 mm.

Next, the horizontal directivity of the wireless antenna device provided in the video camera according to the second embodiment will be described with reference to FIG. In FIG.
Reference numeral 1 denotes a flat antenna unit in the present embodiment, 4 denotes a video camera equipped with the flat antenna unit 31, 12 denotes a photographer who turns the video camera 4 toward the subject 15, and 13 denotes a flat antenna unit in the present embodiment. The directivity pattern 14 is the directivity pattern of the antenna according to the conventional example, 1
Reference numeral 5 denotes a subject that emits sound to the wireless microphone. In FIG. 3, the video camera 4 is carried on the shoulder of the photographer 12 and is directed toward the subject 15.

In the second embodiment of the present invention, the directivity of the planar antenna section 31 is directed in the forward direction of the video camera 4, and the directivity pattern 13 is as shown in FIG. The directional gain in the maximum gain direction (direction of the subject) is about 5 to 6 dBi.
On the other hand, the conventional sleeve antenna 5 shown in FIG.
Since the directivity in the horizontal plane is omni-directional, the directivity pattern 14 is a circular directivity pattern as shown in FIG. 3, and the gain in the subject direction is about 2.1 dBi.

That is, as described above, according to the planar antenna section of the present embodiment, by forming the antenna array, the directional gain is smaller than the directional gain of the conventional sleeve antenna of about 2.1 dBi. Significantly high results of about 5-6 dBi can be obtained.

(Third Embodiment) Hereinafter, a configuration of a wireless antenna device provided in a video camera according to a third embodiment of the present invention will be described with reference to FIG. The wireless antenna device according to the present embodiment is configured so that a planar antenna unit 41 as shown in FIG. 4, reference numeral 2 denotes a receiving device for demodulating a received audio signal, reference numeral 4 denotes a video camera for photographing a subject, and reference numeral 41 denotes a wireless microphone transmitter 17 fixed to the front of the video camera 4 and carried by the subject (see FIG. 5). ) Is a connecting cable for connecting the flat antenna section 41 to the receiving device 2.

In FIG. 4, since the flat antenna section 41 is disposed in front of the video camera 4, there is no interference such as a handle or a photographer's head in the direction of the subject, so the first embodiment shown in FIG. A higher antenna gain can be ensured as compared with the case of the embodiment. The configuration and mounting position of the planar antenna units 1, 31, and 41 described above are not limited to the configuration described above, and any other configuration and mounting position can be obtained as long as a similar directional gain can be obtained. The mounting position may be used, and a similar effect can be obtained.

(Fourth Embodiment) Hereinafter, FIG.
A configuration of a wireless antenna device incorporated in a wireless microphone according to a fourth embodiment of the present invention will be described with reference to FIGS. In FIGS. 5A to 5C, reference numeral 17 denotes a wireless microphone transmission for converting an audio signal received from the microphone unit 26 into a high-frequency transmission signal and transmitting the high-frequency transmission signal via the dielectric helical antenna 18 and the loop antenna 20. And 18 a dielectric helical antenna (first antenna) which is formed on a dielectric and is arranged below the wireless microphone, and 19 transmits a high frequency transmission signal to be transmitted from the high frequency signal switching circuit 22 to the dielectric helical antenna 18. It is a transmission line.

Reference numeral 20 denotes a loop antenna (second antenna) disposed above the wireless microphone, 21
Is a transmission line for transmitting a high-frequency transmission signal to be transmitted from the high-frequency signal switching circuit 22 to the loop antenna 20, and 22 is a transmission line for transmitting the high-frequency transmission signal from the transmission circuit 24 to the helical antenna 18.
Or a high-frequency signal switching circuit for selectively switching to the loop antenna 20; 23, a directional coupler for guiding a reflected signal from the helical antenna 18 or the loop antenna 20 to the detection control unit 25; 24, a sound electric signal from the microphone unit 26; A transmission circuit that modulates the signal and outputs a high-frequency transmission signal;
5 detects the reflected signal from the helical antenna 18 or the loop antenna 20 and switches the high-frequency signal switching circuit 22 to change the high-frequency transmission signal to the antenna 18 with the smaller reflected signal;
A detection control unit for transmitting the sound from the microphone 20; a microphone unit for receiving the sound and converting the sound to an electric sound signal;
Is a hand such as a human body.

That is, in FIG. 5A, the dielectric helical antenna 18 is configured as a helical antenna (dielectric chip antenna) having a dielectric structure, and is located on the opposite side (lower side) of the microphone section 26 inside the wireless microphone transmitter 17. Side). Dielectric helical antenna 1
Reference numeral 8 is electrically connected to one switching terminal of the high-frequency signal switching circuit 22 via the transmission line 19. The loop antenna 20 is formed of a wire such as copper or a metal plate (band), and is configured to surround the housing of the wireless microphone transmitter 17 on the microphone unit 26 side (upper side). The loop antenna 20 is electrically connected to the other switching terminal of the high-frequency signal switching circuit 22 via the transmission line 21.

Next, the operation of the wireless antenna device incorporated in the wireless microphone according to the fourth embodiment of the present invention will be described with reference to FIGS. 5A to 5C. The transmission circuit 24 modulates the audio electric signal received from the microphone unit 26 and outputs a high-frequency transmission signal,
The transmission signal is guided to the high frequency signal switching circuit 22 via the directional coupler 23. Here, the directional coupler 23 is
A transmission signal traveling from the transmission circuit 24 to the antenna side is transmitted with almost no loss, and operates to guide a reflected signal from the antenna side to the detection control unit 25.

The detection control unit 25 includes a high-frequency signal switching circuit 2
2, the dielectric helical antenna 1
8 or the level (return loss) of the reflected signal from the loop antenna 20 can be detected. For example, the dielectric helical antenna 18 or the loop antenna 20
Is covered with a hand or the like, the level of the reflected signal from the antenna 18 or 20 covered by the hand or the like becomes large. Then, upon detecting the reflected signal, the detection control unit 25 instructs the high-frequency signal switching circuit 22 to change the currently connected antennas 18 and 20 to the other antennas 20 and
Switch to 18. Therefore, the high-frequency transmission signal from the transmission circuit 24 passes through the terminal of the switched high-frequency signal switching circuit 22 and radiates the radio wave of the high-frequency transmission signal from the dielectric helical antenna 18 or the loop antenna 20 which is not covered with the hand or the like. I do.

That is, the detection control unit 25 can know which one of the dielectric helical antenna 18 and the loop antenna 20 is not covered with the hand or the like and has a better impedance matching state. It can be controlled to transmit through the better antenna.

Next, with reference to FIGS. 5B and 5C, the operation of the microphone transmitter 17 when the microphone transmitter 17 is held by the hand (human body) 27 will be described. FIG. 5B shows a wireless microphone transmitter 1.
7 shows a case where the lower part 7 (the opposite side of the microphone unit 26) is held by the hand 27, and FIG. 5C shows a case where the upper part (near the microphone unit 26) is held by the hand 27. Here, in the case of FIG. 5B, the dielectric helical antenna 1
8 is covered with the hand 27, the proximity effect of the hand causes the impedance of the dielectric helical antenna 18 to fluctuate and the antenna gain to deteriorate. In this case, the detection control unit 25 detects that the impedance matching state of the dielectric helical antenna 18 is poor, and automatically switches the high-frequency signal switching circuit 22 so as to select the loop antenna 20 and transmit the signal therefrom. On the other hand, in the case of FIG. 5C, the detection control unit 25 detects that the impedance matching state of the loop antenna 20 is bad, and selects the dielectric helical antenna 18 to transmit. Automatically switch.

As described above, according to the fourth embodiment of the present invention, it is possible to automatically select and transmit the antenna which is not affected by the hand holding the wireless microphone transmitter. High antenna gain can always be ensured.

(Fifth Embodiment) The configuration of a wireless antenna device incorporated in a wireless microphone according to a fifth embodiment of the present invention will be described below with reference to FIG. In FIG. 6, reference numeral 17 denotes a wireless microphone transmitter which converts an audio signal received from the microphone unit 26 into a high-frequency transmission signal and transmits the converted signal via the dielectric helical antenna 18 and the loop antenna 20; A dielectric helical antenna (first antenna) 19 disposed below the microphone is a transmission line for transmitting a high frequency transmission signal to be transmitted from the circulator 28 to the dielectric helical antenna 18.

Further, reference numeral 20 denotes a loop antenna (second antenna) disposed above the wireless microphone, 21
Is a transmission line for transmitting a high frequency transmission signal to be transmitted from the circulator 28 to the loop antenna 20; 24 is a transmission circuit for modulating an audio electric signal from the microphone unit 26 to output a high frequency transmission signal; The microphone unit 28 transmits a transmission signal from the transmission circuit 24 to the dielectric helical antenna 18 and, if there is a reflected signal from the dielectric helical antenna 18, a circulator that transmits the reflected signal to the loop antenna 20. is there.

Next, the operation of the wireless antenna device incorporated in the wireless microphone according to the fifth embodiment of the present invention will be described with reference to FIG. For example, FIG.
(B), when the lower part of the wireless microphone transmitter 17 is held by the hand 27, the impedance matching state of the dielectric helical antenna 18 deteriorates.
The high-frequency transmission signal is reflected by the dielectric helical antenna 18 and transmitted to the loop antenna 20 via the circulator 28. Also, as shown in FIG. 5C, when the upper part of the wireless microphone transmitter 17 is held by the hand 27, the impedance matching state of the dielectric helical antenna 18 is good, so that the transmission signal is transmitted to the dielectric helical antenna 18 And is not transmitted to the loop antenna 20 because there is no reflection.

As described above, according to the fifth embodiment of the present invention, the antenna which is not affected by the hand holding the wireless microphone transmitter can be automatically selected and transmitted. High antenna gain can always be ensured.

[0050]

The present invention is configured as described above, and in particular,
By using a planar antenna unit, the height of the antenna projecting above the video camera can be kept low to avoid interference with obstacles. With the configuration using the antenna element, it is possible to provide a wireless antenna device of a wireless receiving device mounted on a video camera capable of always directing the antenna directivity toward the wireless microphone transmitter and obtaining a high directivity gain. .

According to the present invention, the wireless microphone transmitter is provided with two wireless antenna devices, and the wireless antenna device having the wireless microphone transmitter which is not affected by the hand is automatically selected and transmitted. Therefore, it is possible to provide a wireless antenna device of a wireless microphone transmitter that can always ensure a high antenna gain.

[Brief description of the drawings]

FIG. 1 is a basic conceptual diagram of a video camera equipped with a wireless antenna device according to a first embodiment of the present invention.

FIG. 2 is a basic conceptual diagram of a wireless antenna device provided in a video camera according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of an operation of a wireless antenna device according to a second embodiment of the present invention.

FIG. 4 is a basic conceptual diagram of a video camera equipped with a wireless antenna device according to a third embodiment of the present invention.

FIGS. 5A and 5B are diagrams illustrating a configuration of a wireless microphone transmitter according to a fourth embodiment of the present invention, in which FIG. 5A illustrates a configuration of a wireless antenna device incorporated in the wireless microphone transmitter, and FIG. Figure showing a state where the lower part of the microphone is held by hand. (C) is a figure showing a state where the upper part of the wireless microphone is held by hand.

FIG. 6 is a diagram showing a configuration of a wireless antenna device incorporated in a wireless microphone transmitter according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a wireless antenna device in which a sleeve antenna unit is fixed on a conventional video camera.

FIG. 8 is a configuration diagram of a conventional wireless antenna device configured with an inverted L antenna disposed inside a wireless microphone housing.

[Explanation of symbols]

 1, 31, 41 Planar antenna unit 2 Receiving device 3 Connector unit 4 Video camera 5 Sleeve antenna unit 6 Dielectric substrate 7 Ground plate 8a to 8d Planar antenna element 9a to 9d Through hole 10a, 10b Power distributor 11a, 11b Connector unit 12 Photographer (human body) 13 Directivity in the present invention 14 Directivity in conventional example 15 Subject 16 Connection cable 17 Wireless microphone transmitter 18 Dielectric helical antenna 19 Transmission line 20 Loop antenna 21 Transmission line 22 High frequency signal switching circuit 23 Directivity Coupler 24 Transmission circuit 25 Detection control unit 26 Microphone unit 27 Hand (human body) 28 Circulator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04R 1/04 H04R 1/04 Z

Claims (6)

[Claims] 1. A video camera, comprising: a planar antenna section; a receiving device to which the planar antenna section is electrically connected; and a video camera to which the receiving apparatus is fixed. A wireless antenna device, wherein the wireless antenna device is directed to the front of a vehicle. 2. The wireless antenna device according to claim 1, wherein said planar antenna section is configured as a planar antenna array by a plurality of planar antennas. 3. The wireless antenna device according to claim 1, wherein the flat antenna unit is mounted on a front part of a video camera. 4. A first antenna disposed below a wireless microphone, a second antenna disposed near a microphone unit at a predetermined distance from the first antenna,
A transmission circuit that processes an audio signal from the microphone unit and outputs a high-frequency transmission signal; a high-frequency signal switching circuit that switches a high-frequency transmission signal from the transmission circuit to one of a first antenna and a second antenna; The first signal is inserted between a high-frequency signal switching circuit and the transmitting circuit.
A directional coupler that detects a reflection component of a high-frequency transmission signal from the antenna and the second antenna, and receives a detection result of the reflection component by the directional coupler, and converts the high-frequency transmission signal from the transmission circuit to a component having a smaller reflection component; A detection control unit that switches the high-frequency signal switching circuit to be connected to an antenna, wherein the detection control unit controls the first antenna and the second antenna.
A wireless antenna device, wherein an antenna having a smaller reflection component is selected from the antennas, and a high-frequency transmission signal from the transmission circuit is automatically switched to an antenna having a smaller reflection component and transmitted. 5. A first antenna disposed below a wireless microphone, a second antenna disposed near a microphone unit at a predetermined distance from the first antenna,
A transmission circuit that processes and outputs a voice transmission signal from the microphone unit; a circulator that transmits a high-frequency transmission signal from the transmission circuit to a first antenna and transmits a reflection signal from the first antenna to a second antenna With
An antenna that transmits a high-frequency transmission signal from the transmission circuit to the first antenna and transmits the signal, and when there is a reflected signal from the first antenna, automatically transmits the signal to the second antenna via the circulator and transmits the signal. A wireless antenna device, wherein the wireless antenna device is selected. 6. The wireless antenna device according to claim 4, wherein said first antenna is constituted by a helical antenna, and said second antenna is constituted by a loop antenna.