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JPH1188748

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JPH1188748
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
wireless microphone device and a wireless antenna device of a wireless receiving device
equipped in a video camera.
[0002]
2. Description of the Related Art The antenna configuration of a receiving apparatus for a
wireless microphone which is conventionally connected to a video camera and receives a
transmission signal from a wireless microphone apparatus is as disclosed in, for example,
Japanese Utility Model Application Laid-Open No. 62-53867. A downturn antenna pole has been
generally used.
[0003]
Also, as another conventional example, a configuration in which a monopole antenna or a sleeve
antenna unit as shown in FIG. 7 is fixed to the upper part of a video camera has been used.
That is, in FIG. 7, 2 is a receiver for demodulating a received audio signal, 4 is a video camera for
photographing an object, 5 is a wireless microphone transmitter fixed to the upper portion of the
receiver 2 and carried by the object. The sleeve antenna unit 3 receives a radio wave of the
above, and 3 is a connector unit for connecting the sleeve antenna unit 5 to the receiving device
01-05-2019
1
2. In general, in the wireless antenna of this type of wireless microphone device, the 800 MHz
band (wavelength about 380 mm) is used, and the height of the sleeve antenna portion 5
protruding above the video camera 4 is usually 2 minutes It is about one wavelength (about 190
mm).
[0004]
The video camera 4 is a portable imaging and recording apparatus. In general, a photographer
carries a shoulder on his / her shoulder and shoots a subject facing the subject. 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
the 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. The sleeve antenna unit 5 is
electrically connected to the receiving device 2 via the connector unit 3 and mechanically fixed.
[0005]
Further, since the directivity in the horizontal plane of the sleeve antenna is non-directional, in
this conventional example, although the wireless microphone transmitter is always in front of the
video camera 4, the directivity of the antenna of the receiving apparatus is all It will be turned in
the direction. In this case, the gain of the sleeve antenna is generally about 2.1 dBi.
[0006]
Also, as a built-in antenna of a conventional wireless microphone transmitter, for example, one
configured by arranging a monopole antenna and a dipole antenna inside a wireless microphone
case has been used. In addition, as an example of the wireless microphone built-in antenna of
another example, one constituted by an inverted L antenna disposed inside a wireless
microphone casing (disclosed in Japanese Patent Laid-Open No. 9-98494) as shown in FIG. It has
been known.
[0007]
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2
That is, in FIG. 8, the lead wire 4 is connected to the antenna element 1, the power feeding
connector 5 is connected to a predetermined position of the printed board 2, and the antenna
element 1 and the printed board 2 are disposed in parallel. An inverted L antenna structure is
constructed. Further, the parasitic element 3 for impedance matching is disposed 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 becomes optimum. I am
trying to
[0008]
Among the wireless antenna devices according to the prior art as described above, regarding the
configuration of the wireless antenna device of the receiving device for a wireless microphone
connected to a video camera, a wireless antenna protruding above the video camera Is relatively
long at about a half wavelength (about 190 mm), there is a problem that it is easy to contact an
obstacle during the photographing operation and there are many failures due to breakage.
[0009]
Further, in the configuration of the conventional wireless antenna device used for the video
camera as described above, the directivity of the wireless antenna is almost non-directive in the
horizontal plane, so in general, the direction in which the video camera is facing There is a
problem that the antenna gain in the forward direction of the video camera, which is the
direction of the object to be photographed or the subject) can not be increased.
[0010]
Among the wireless antenna devices according to the conventional example as described above,
in the wireless antenna device incorporated in the wireless microphone transmitter, the gain of
the wireless antenna is degraded due to the proximity effect of the hand depending on the
position of the hand holding the wireless microphone There was a problem that the degree of
change greatly changed.
For example, when a wireless microphone having a wireless antenna at the bottom is held by
hand, degradation of the wireless antenna gain is large, generally, about 10 to 15 dB.
On the other hand, when holding the top of the wireless microphone, ie, in the vicinity of the
microphone without the wireless antenna, there is almost no deterioration of the wireless
01-05-2019
3
antenna gain.
[0011]
The present invention has been made to solve the above-described conventional problems, in
which the height of the wireless antenna protruding above the video camera is lowered to
prevent damage, and the directivity of the wireless antenna is made in front of the video camera.
It is an object of the present invention to provide a wireless antenna device of a wireless
receiving device equipped to a video camera with high antenna gain secured by aiming.
[0012]
Another object of the present invention is to provide a wireless antenna device mounted on a
wireless microphone device (wireless microphone transmitter) capable of securing high antenna
gain regardless of the position of the wireless microphone device. .
[0013]
SUMMARY OF THE INVENTION A wireless antenna device of a wireless receiver equipped in a
video camera according to the present invention comprises a planar antenna array composed of
one or more planar antennas at the top of the video camera and disposed toward the object. It is
intended to
The present invention uses a planar antenna to lower the height of the wireless antenna
projecting above the video camera to prevent damage, and arranges the planar antenna at the
object to video the directivity of the wireless antenna. By pointing in front of the camera, it is
possible to obtain a wireless antenna device capable of securing high antenna gain.
[0014]
The wireless antenna device incorporated in the wireless microphone transmitter according to
the present invention has a first wireless antenna disposed under the wireless microphone
transmitter and a second wireless antenna disposed above the wireless microphone transmitter.
The reflected component of the high frequency transmission signal from the antenna and the
second antenna is detected, and the wireless antenna with the smaller reflected component is
automatically selected, switched, and transmitted.
01-05-2019
4
The present invention automatically selects and switches the wireless antenna (the first antenna
or the second antenna) where the wireless microphone transmitter is not held by hand regardless
of where the hand is held by the hand. A wireless antenna arrangement for a wireless
microphone transmitter is provided which can ensure gain.
[0015]
A wireless antenna device incorporated in a wireless microphone transmitter according to the
present invention has a first wireless antenna disposed under the wireless microphone
transmitter and a second wireless antenna disposed above the wireless microphone transmitter
for high frequency transmission. A signal is automatically transmitted from the first antenna, and
if there is a reflected component from the first antenna, it is automatically selected and switched
and transmitted so that it is transmitted to the second antenna and transmitted. is there. The
present invention automatically selects and switches the wireless antenna (the first antenna or
the second antenna) where the wireless microphone transmitter is not held by hand regardless of
where the hand is held by the hand. A wireless antenna arrangement for a wireless microphone
transmitter is provided which can ensure gain.
[0016]
According to the first aspect of the present invention, there is provided a planar antenna unit, a
receiving apparatus to which the planar antenna unit is electrically connected, and a video
camera to which the receiving apparatus is fixed. The directivity formed by the flat antenna unit
is directed to the front of the video camera, and the height of the wireless antenna protruding
above the video camera is lowered to prevent damage, and the wireless antenna is directed. By
directing the sex to the front of the video camera, it has the effect that high antenna gain can be
secured.
[0017]
In the invention according to claim 2 of the present invention, the planar antenna unit is
configured as a planar antenna array by a plurality of planar antennas, and the antenna
directivity gain in the forward direction of the video camera is further increased. It has the effect
of
01-05-2019
5
In the invention according to claim 3 of the present invention, the flat antenna unit is attached to
the front of the video camera, and there is no interference such as a handle or the head of the
photographer in the direction of the subject. It has the effect that a higher antenna gain can be
secured.
[0018]
According to a fourth aspect of the present invention, there is provided a first antenna disposed
under the wireless microphone, a second antenna spaced a predetermined distance from the first
antenna, and disposed in the vicinity of the microphone portion, and the microphone portion
Transmission circuit for processing an audio transmission signal from the transmitter to output a
high frequency transmission signal, a high frequency signal switching circuit for switching the
high frequency transmission signal from the transmission circuit to either the first antenna or the
second antenna, and A directional coupler inserted between the signal switching circuit and the
transmission circuit and detecting a reflection component of the high frequency transmission
signal from the first antenna and the second antenna, and a detection result of the reflection
component by the directional coupler Detection that switches the high-frequency signal
switching circuit to connect the high-frequency transmission signal from the transmission circuit
to the antenna with the smaller reflection component A control unit, and the detection control
unit selects an antenna with less reflected components from the first antenna and the second
antenna, and automatically transmits a high-frequency transmission signal from the transmitting
circuit to the antenna with less reflected components It has an effect that high antenna gain can
be secured regardless of the position held by the wireless microphone device by hand.
[0019]
According to a fifth aspect of the present invention, there is provided a first antenna disposed
under the wireless microphone, a second antenna spaced a predetermined distance from the first
antenna, and disposed in the vicinity of the microphone portion, and the microphone portion A
transmission circuit for processing and outputting an audio transmission signal from the
transmitter, and a circulator for transmitting the high frequency transmission signal from the
transmission circuit to the first antenna and transmitting the reflection signal from the first
antenna to the second antenna; The high frequency transmission signal from the transmission
circuit is transmitted to the first antenna and transmitted, and when there is a reflected signal
from the first antenna, the antenna automatically transmits to be transmitted and transmitted to
the second antenna via the circulator. The configuration of the antenna selection circuit is
simplified and the entire device is miniaturized, and the wireless microphone device Regardless
of the position gripped by, an effect that it is possible to secure high antenna gain.
01-05-2019
6
[0020]
The invention according to claim 6 of the present invention is such that the first antenna is
formed of a helical antenna, and the second antenna is formed of a loop antenna, and the shapes
of the upper and lower portions of the wireless microphone are adapted. This has the effect of
being able to construct a space-saving built-in antenna.
[0021]
Hereinafter, embodiments of the present invention will be described in detail with reference to
the attached drawings and FIGS. 1 to 6.
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. 2 is a basic concept of a
wireless antenna device mounted in a video camera according to a second embodiment of the
present invention. FIG. 3 is an explanatory view of the operation of the wireless antenna device in
the second embodiment of the present invention, and FIG. 4 is a basic conceptual diagram of a
video camera equipped with the wireless antenna device in the third embodiment of the present
invention FIG. 5 is a diagram showing the configuration of a wireless microphone transmitter
according to a fourth embodiment of the present invention, wherein (A) is a diagram showing the
configuration of a wireless antenna device incorporated in the wireless microphone transmitter,
and (B) is a wireless Fig. 6 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;
In the fifth embodiment of the invention is a diagram showing a configuration of a wireless
antenna device incorporated in a wireless microphone transmitter.
[0022]
First Embodiment First, with reference to FIG. 1, the configuration of a wireless antenna device
provided in a video camera according to a first embodiment of the present invention will be
described.
In FIG. 1, 2 is a receiver for demodulating a received audio signal, 4 is a video camera for
photographing an object, and 1 is a wireless microphone transmitter 17 fixed at the upper part
of the receiver 2 and carried by the object. A planar antenna unit for receiving radio waves from
5), and a connector unit 3 for connecting the planar antenna unit 1 to the receiver 2.
01-05-2019
7
[0023]
Next, with reference to FIG. 1, the operation of the wireless antenna device equipped in the video
camera in the present embodiment will be described.
The video camera 4 is a portable type imaging and recording apparatus, and generally, a
photographer carries on a shoulder and shoots with the subject facing the subject. The receiving
device 2 is a wireless receiving device built in the video camera 4 and, generally, receives an
electric wave from the wireless microphone transmitter 17 carried by a subject such as a person,
and the video signal 4 is demodulated. Enter in The video camera 4 records an audio signal input
from the receiving device 2 together with an image. The planar antenna unit 1 is electrically
connected to the receiving device 2 through the connector unit 3 and mechanically fixed by the
connector unit 3.
[0024]
The planar antenna unit 1 is disposed in front of the video camera 4 so that the antenna element
surfaces of the planar antenna unit 1 are directly opposed, and is generally constituted by a
plate-like inverted F antenna formed on a dielectric substrate . It is known that, in a plate-like
inverted F antenna formed on a dielectric substrate, the antenna element resonates at a
peripheral length of λg / 2 (λg is a wavelength on the dielectric substrate). For example, when
the relative dielectric constant of the dielectric substrate in the 800 MHz band is selected to be
about 3.6, the length of one side of the antenna element, that is, the height of the projection
above the video camera 4 is about 24 mm.
[0025]
Further, since the antenna elements (plate-like inverted F antenna) of the planar antenna unit 1
are disposed to face the front of the video camera 4, the directivity of the planar antenna is
directed to the front of the video camera 4. . Since the video camera 4 is always directed to the
subject (person or the like), the directivity of the planar antenna can be directed to the wireless
microphone transmitter 17 carried by the subject (person or the like). In this case, the directional
gain in the maximum gain direction of the planar antenna can generally be obtained about 3 to 4
01-05-2019
8
dBi.
[0026]
As described above, since the directivity in the horizontal plane of the sleeve antenna 5 in the
above-mentioned conventional example is non-directional, the sleeve antenna of the receiver 2 is
in spite of the fact that the wireless microphone transmitter 17 is always in front of the video
camera 4 The directivity of 5 will be directed in all directions. In this case, the gain of the sleeve
antenna 5 is generally about 2.1 dBi.
[0027]
As described above, according to the first embodiment of the present invention, the height of the
planar antenna portion 1 projecting on the upper portion of the video camera is approximately
one seventh of that of the sleeve antenna 5 in the conventional example. Can avoid problems that
interfere with obstacles. In addition, since the antenna directivity of the receiver 2 connected to
the video camera 4 can always be directed to the direction of the wireless microphone
transmitter 17, its directivity gain is about 3 to 4 dBi, which is about 2. in the above conventional
example. A directivity gain much higher than 1 dBi can be obtained.
[0028]
Second Embodiment The configuration of a wireless antenna device provided in a video camera
according to a second embodiment of the present invention will be described below with
reference to FIG. In FIG. 2, 31 is a planar antenna unit which comprises a plurality of planar
antenna elements 8a to 8d and is fixed to the upper part of the receiver 2 to receive radio waves
from the wireless microphone transmitter 17 (FIG. 5) carried by the subject. Reference numerals
8a to 8d denote a plurality of planar antenna elements constituting the planar antenna unit 31,
and reference numeral 6 denotes a dielectric substrate on which the plurality of planar antenna
elements 8a to 8d are formed by etching, plating, sticking or other means.
[0029]
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9
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 are provided on
the planar antenna elements 8a to 8d. Through holes, 10a and 10b are power dividers that
combine received signals from the planar antenna elements 8a to 8d and output the combined
signal to the receiving device 2, and 11a and 11b are connector portions that connect the planar
antenna unit 31 to the receiving device 2 It is. The video camera 4 and the receiving device 2 are
the same as those shown in FIG.
[0030]
Next, with reference to FIG. 3, the operation of the wireless antenna device provided in the video
camera in the second embodiment will be described. 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 (but may have any other size). The dielectric substrate
6 is mounted on the ground plate 7, and the ground plate 7 operates as a ground plane for the
planar antenna elements 8 a to 8 d configured on the dielectric substrate 6. Further, the ground
plate 7 is connected to the ground side of the connector portions 11a and 11b, and operates as a
ground plane of the entire planar antenna portion 31. The planar antenna elements 8a to 8d
respectively constitute a plate-like inverted F antenna. Through holes 9a to 9d operate as ground
contacts of plate-like inverted F antennas formed by planar antenna elements 8a to 8d,
respectively.
[0031]
The power distributors 10 a and 10 b are formed of microstrip lines on the dielectric substrate 6.
The received signals from the planar antenna elements 8a and 8b are combined by the power
distributor 10a and guided to the connector portion 11a. The received signals from the planar
antenna elements 8c and 8d are combined by the power distributor 10b and guided to the
connector portion 11a. As described above, the planar antenna elements 8a and 8b and the
planar antenna elements 8c and 8d constitute two sets of antenna arrays. By configuring the
antenna array with the planar antenna elements 8a and 8b and 8c and 8d, the directivity of each
of the planar antenna elements 8a and 8b and 8c and 8d is synthesized, and a high directivity
gain in the front direction is obtained. You can get
[0032]
01-05-2019
10
In this case, generally, a directional gain of about 5 to 6 dBi can be obtained in the maximum
gain direction. A space diversity antenna is configured by configuring two sets of antenna arrays
(8a and 8b and 8c and 8d). Here, the height of the planar antenna unit 31 in the 800 MHz band
is obtained by adding the length of one side (approximately 24 mm) of the planar antenna
elements 8 a to 8 d and the length (approximately 15 mm) of the power distributors 10 a to 10
b. The length can be made approximately equal, and can be reduced to about 40 mm.
[0033]
Next, with reference to FIG. 3, the horizontal direction directivity of the wireless antenna device
equipped in the video camera in the second embodiment will be described. In FIG. 3, 1 is a flat
antenna unit in the present embodiment, 4 is a video camera equipped with the flat antenna unit
31, 12 is a photographer pointing the video camera 4 in the direction of the subject 15, 13 is a
flat surface in the present embodiment The directivity pattern of the antenna unit 31, 14
indicates the directivity pattern of the antenna according to the conventional example, and 15
indicates 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 directed toward the subject 15.
[0034]
In the second embodiment of the present invention, the directivity of the planar antenna unit 31
is directed in the forward direction of the video camera 4, and the directivity pattern 13 is as
shown in FIG. Then, the directivity gain with respect to the maximum gain direction (the direction
of the object) is about 5 to 6 dBi. On the other hand, since the directivity in the horizontal plane
of the sleeve antenna 5 according to the prior art shown in FIG. 2 is non-directional, the
directivity pattern 14 becomes a circular directivity pattern as shown in FIG. Is about 2.1 dBi.
[0035]
That is, as described above, according to the planar antenna unit in the present embodiment, by
configuring the antenna array, the directivity gain is about 5 to 5 as compared with the
directivity gain of about 2.1 dBi of the conventional sleeve antenna. A fairly high result of 6 dBi
can be obtained.
[0036]
01-05-2019
11
Third Embodiment The configuration of a wireless antenna device provided in a video camera
according to a third embodiment of the present invention will be described below with reference
to FIG.
The wireless antenna device in the present embodiment is configured to arrange a flat antenna
unit 41 as shown in FIG. 1 in the front part of the video camera 4. In FIG. 4, 2 is a receiver for
demodulating the received audio signal, 4 is a video camera for photographing an object, 41 is a
wireless microphone transmitter 17 fixed at the front of the video camera 4 and carried by the
object (FIG. And a connecting cable 16 for connecting the planar antenna unit 41 to the receiving
device 2. As shown in FIG.
[0037]
In FIG. 4, since the planar antenna unit 41 is disposed in the front of the video camera 4, there is
no interference such as a handle or a photographer's head in the direction of the object, so that
the first embodiment shown in FIG. Higher antenna gains can be ensured compared to the ones.
The configurations and mounting positions of the planar antenna units 1, 31, 41 described above
are not limited to the configurations described above, and any other configuration and mounting
position can be used if configuration and mounting positions where similar directivity gain can
be obtained are obtained. It may be a mounting position, and the same effect can be obtained
thereby.
[0038]
Fourth Embodiment A configuration of a wireless antenna device incorporated in a wireless
microphone according to a fourth embodiment of the present invention will be described below
with reference to FIGS. 5A to 5C. Do. In (A) to (C) of FIG. 5, wireless microphone transmission 17
converts an audio signal received from the microphone unit 26 into a high frequency
transmission signal and transmits the high frequency transmission signal through the dielectric
helical antenna 18 and the loop antenna 20. , 18 is a dielectric helical antenna (first antenna)
arranged on the lower part of the wireless microphone and configured on a dielectric, 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.
01-05-2019
12
[0039]
Further, 20 is 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
circuit from the transmission circuit 24. A high frequency signal switching circuit which selects
and switches a high frequency transmission signal to the helical antenna 18 or the loop antenna
20, 23 is 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 is a microphone A transmitter circuit that
modulates the electric signal from the audio unit 26 and outputs a high frequency transmission
signal. 25 detects a reflection signal from the helical antenna 18 or the loop antenna 20 and
switches the high frequency signal switching circuit 22 to reflect the high frequency
transmission signal Transmit from the lesser antenna 18, 20 Controller output, 26 microphone
unit for converting the electric voice signal receiving sound, 27 is a hand of the human body or
the like.
[0040]
That is, in FIG. 5A, the dielectric helical antenna 18 is configured as a helical antenna (dielectric
chip antenna) having a dielectric structure, and on the opposite side (lower side) of the
microphone unit 26 in the wireless microphone transmitter 17. Be placed.
The dielectric helical antenna 18 is electrically connected to one of the switching terminals of the
high frequency signal switching circuit 22 through the transmission line 19. The loop antenna 20
is formed of a wire or metal plate (band) such as copper, and is configured to surround the
periphery of 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.
[0041]
Next, with reference to FIGS. 5A to 5C, the operation of the wireless antenna device incorporated
in the wireless microphone in the fourth embodiment of the present invention will be described.
The transmission circuit 24 modulates the electrical audio signal received from the microphone
unit 26 to output a high frequency transmission signal, and the transmission signal is led to the
high frequency signal switching circuit 22 via the directional coupler 23. Here, the directional
01-05-2019
13
coupler 23 operates so as to transmit the transmission signal traveling from the transmission
circuit 24 to the antenna side with almost no loss, while guiding the reflection signal from the
antenna side to the detection control unit 25.
[0042]
The detection control unit 25 can detect the level (return loss) of the reflected signal from the
dielectric helical antenna 18 or the loop antenna 20 according to the connection state in the high
frequency signal switching circuit 22. For example, when 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 with the hand or the like is increased. When the detection control unit
25 detects the reflection signal, the detection control unit 25 instructs the high frequency signal
switching circuit 22 to switch the currently connected antenna 18, 20 from that to the other
antenna 20, 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 radio waves of the high frequency transmission signal from the dielectric helical antenna
18 or the loop antenna 20 which is not covered by hand or the like. Do.
[0043]
That is, detection control unit 25 is not covered by hand or the like among dielectric helical
antenna 18 and loop antenna 20, and can know the antenna having a better state of impedance
matching, and always has a good state of impedance matching. Can be controlled to transmit
through the other antenna.
[0044]
Next, with reference to FIGS. 5B and 5C, the operation of the microphone microphone 17 in a
state in which the microphone 17 is held by the hand (human body) 27 will be described.
FIG. 5B shows the case where the lower part of the wireless microphone transmitter 17 (the
opposite side of the microphone unit 26) is held by the hand 27, and FIG. 5C the upper part (near
the microphone unit 26) by the hand 27. It shows the case of holding. Here, in the case of FIG.
5B, since the periphery of the dielectric helical antenna 18 is covered with the hand 27, the
impedance of the dielectric helical antenna 18 fluctuates and the antenna gain is degraded due to
the proximity effect of the hand. . In this case, the detection control unit 25 detects that the
01-05-2019
14
impedance matching state of the dielectric helical antenna 18 is bad, selects the loop antenna 20
and automatically switches the high frequency signal switching circuit 22 to transmit from there.
On the other hand, in the case of (C) of FIG. 5, 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. Switch automatically.
[0045]
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 having the
wireless microphone transmitter, so that the antenna is always high. Gain can be secured.
[0046]
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, 17 is a wireless microphone transmitter that converts an audio signal received from the
microphone unit 26 into a high frequency transmission signal and transmits it via the dielectric
helical antenna 18 and the loop antenna 20, and 18 is configured on the dielectric and wireless A
dielectric helical antenna (first antenna) disposed under the microphone, and 19 are transmission
lines for transmitting a high frequency transmission signal to be transmitted from the circulator
28 to the dielectric helical antenna 18.
[0047]
Further, 20 is 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 an audio electrical signal from the microphone
unit 26 , A microphone unit that receives a voice and converts it into an electric signal, transmits
a transmission signal from the transmission circuit 24 to the dielectric helical antenna 18, and
the dielectric helical antenna If there is a reflected signal from 18, it is a circulator that transmits
the reflected signal to the loop antenna 20.
[0048]
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15
Next, with reference to FIG. 6, the operation of the wireless antenna device incorporated in the
wireless microphone in the fifth embodiment of the present invention will be described.
For example, as shown in FIG. 5B, 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 is
deteriorated, so that the high frequency transmission signal is dielectric helical. The light is
reflected by the antenna 18 and transmitted to the loop antenna 20 through 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 the
transmission signal is the dielectric helical antenna 18 And not transmitted to the loop antenna
20 because there is no reflection.
[0049]
As described above, according to the fifth embodiment of the present invention, it is possible to
automatically select and transmit the antenna which is not affected by the hand having the
wireless microphone transmitter, so that the antenna is always high. Gain can be secured.
[0050]
The present invention is configured as described above, and in particular, by using a flat antenna
section, the height of the antenna protruding above the video camera can be reduced to avoid
interference with obstacles. The antenna directivity can be always directed to the direction of the
wireless microphone transmitter, and high directivity gain can be obtained by orienting the
planar antenna unit toward the subject and configuring it with a plurality of planar antenna
elements. It is possible to provide a wireless antenna device of a wireless receiver equipped in a
video camera.
[0051]
Also, the present invention equips the wireless microphone transmitter with two wireless
antenna devices, and automatically selects and transmits the wireless antenna device on the side
that is not affected by the hand holding the wireless microphone transmitter. It is possible to
provide a wireless antenna device of a wireless microphone transmitter that can always ensure
high antenna gain.
[0052]
Brief description of the drawings
01-05-2019
16
[0053]
1 is a basic conceptual diagram of a video camera equipped with a wireless antenna device
according to the first embodiment of the present invention
[0054]
2 is a basic conceptual diagram of a wireless antenna device equipped in a video camera
according to the second embodiment of the present invention
[0055]
3 is an explanatory view of the operation of the wireless antenna device in the second
embodiment of the present invention
[0056]
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
[0057]
5 is a diagram showing the configuration of the wireless microphone transmitter in the fourth
embodiment of the present invention, (A) is a diagram showing the configuration of the wireless
antenna device incorporated in the wireless microphone transmitter
[0058]
<Figure 6> The figure which shows the constitution of the wireless antenna device which is built
into the wireless microphone transmitter in the form of 5th execution of this invention
[0059]
Fig. 7 A block diagram of a wireless antenna apparatus in which a sleeve antenna unit is fixed to
the upper part of a conventional video camera
[0060]
Fig. 8 A block diagram of a wireless antenna device configured with an inverted L antenna
disposed inside a conventional wireless microphone housing
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[0061]
Explanation of sign
[0062]
1, 31, 41 Flat Antenna Unit 2 Receiver 3 Connector Unit 4 Video Camera 5 Sleeve Antenna Unit 6
Dielectric Substrate 7 Ground Plates 8a to 8d Flat Antenna Elements 9a to 9d Through Hole 10a,
10b Power Divider 11a, 11b Connector Unit 12 photographer (human body) 13 directivity in the
present invention 14 directivity in the conventional example 15 object 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
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18
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