JP2004096207A - Dipole antenna having cylindrical reflector with closed upper end - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dipole antenna having a cylindrical reflector whose upper end is closed that averages signal reception strength in a mobile phone service area. <P>SOLUTION: In the dipole antenna having a cylindrical reflector 3 whose upper end is closed, two dipole antennas 1, 1' of the same shape and driven by the same amplitude with different phase by 60 degrees are placed and arranged in a line along a Z axis by placing the dipole antenna 1' driven with a phase led by 60 degrees under the dipole antenna 1, and the cylindrical reflector 3 whose upper end is closed and resulting from integration of a cylindrical reflector 31 and a disk reflector 32 coupled and fixed to an open upper end of the cylindrical reflector 31 is placed under the two dipole antennas 1, 1'. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a dipole antenna with a closed-end cylindrical reflector, and more particularly, to a dipole antenna with a closed-end cylindrical reflector used in an IMT-2000 in-building service in a mobile communication device.
[0002]
[Prior art]
2. Description of the Related Art A mobile phone base station receives a signal sent from a user's mobile phone, and adjusts the amplification of the signal based on the reception level. That is, when a base station receives a signal transmitted from a user's mobile phone located in the vicinity of the antenna, the reception level of the signal transmitted from the mobile phone is high, so that the amplification degree of the signal is relatively high. Adjust smaller. On the other hand, when a signal transmitted from the mobile phone of the user located at the edge of the service area of the mobile phone is received, since the reception level of the transmitted signal transmitted from the mobile phone is low, the amplification of the signal is reduced. Adjust relatively large.
[0003]
[Problems to be solved by the invention]
By the way, when the base station happens to receive a signal of a large reception level transmitted from a user's mobile phone located near the antenna and adjust the amplification of the signal to a relatively small level, the service area of the mobile phone The electric field strength at the end becomes small, and the user's mobile phone located there may not be able to communicate well with the base station.
According to the present invention, an upper end closed cylindrical reflector is arranged below two dipole antennas arranged in a line on the Z axis to direct the directivity of the antenna toward the edge of the service area of a mobile phone, and It is an object of the present invention to provide a dipole antenna with a closed-end cylindrical reflector which solves the above-mentioned problem of generating a radiation pattern in which a radiation beam is suppressed in the above.
[0004]
[Means for Solving the Problems]
Two dipole antennas 1 and 1 ′ driven in the same shape and with different phases by 60 ° and with the same amplitude are arranged in a row on the Z-axis with the dipole antenna 1 ′ driven by advancing the phase by 60 ° on the lower side. The upper-end closed cylindrical reflector 3 integrated with a disk reflector 32 connected and fixed to the open upper end of the cylindrical reflector 31 is disposed below the two dipole antennas 1, 1 '. A dipole antenna with the disposed top closed cylindrical reflector 3 was constructed.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the embodiment of FIG.
Two dipole antennas 1 and 1 'having the same shape are arranged in a line on the Z axis which is a vertical direction. The dipole antenna 1 is driven by a signal source 2, and the dipole antenna 1 'is driven by a signal source 2'. The signal source 2 ′ generates a signal whose phase is advanced by 60 ° as compared with the signal source 2. The lower dipole antenna 1 ′ of the two dipole antennas 1 and 1 ′ is compared with the upper dipole antenna 1 by the signal source 2 ′ whose phase is advanced by 60 ° from the signal source 2. Driven at the same amplitude.
[0006]
A cylindrical reflector 31 made of a metal material and a disk reflector 32 made of a metal material are prepared. The diameter of the cylindrical reflector 31 and the diameter of the disk reflector 32 are made equal to each other, and the disk reflector 32 is fixedly connected to the open upper end of the cylindrical reflector 31 and integrated to form an upper end closed cylindrical reflector. 3 is constituted.
Here, the lower end closed cylindrical reflector 3 with the disc reflector 3 facing upward is positioned below the two dipole antennas 1 and 1 'arranged in a line on the Z axis, and the center thereof is defined as the Z axis. Position it in a state that matches with.
[0007]
FIG. 2 is a diagram showing the directivity pattern of the above embodiment. The diameter D is 110 mm and the height H is 25 mm. FIG. 5 is a diagram showing a directivity pattern of a conventional example of an antenna in which two dipole antennas driven with the same shape, the same phase and the same amplitude are arranged in a line on the Z-axis and have no reflector on the lower side. is there.
Referring to FIGS. 2 and 5, in the embodiment configured as described above, the main radiation beam is directed from the two dipole antennas 1 and 1 ′ in directions of about + 80 ° and about −80 ° with respect to the Z axis. At the same time, a radiation-suppressed radiation pattern is generated within a range of ± 40 ° with respect to the Z axis. Compared to the embodiment of FIG. 5, the directivity of the antenna is directed toward the edge of the service area of the mobile phone, and generates a radiation pattern in which a radiation beam is suppressed in the vicinity of the antenna. The reception intensity can be averaged more.
[0008]
3 and 4 show the calculation results of the main beam direction and F / S using the height H of the cylindrical reflector 51 and the diameter D of the cylindrical reflector 31 and the disk reflector 32 in the embodiment of FIG. Is shown. With the plus direction in the Z-axis direction taken as 0 °, the value having the highest gain within ± 40 ° was defined as F / S.
FIG. 3 shows calculation results of the main beam direction and F / S obtained by changing the height H and setting the diameter D of the closed-end cylindrical reflector 3 to 100 mm. A relatively large F / S is obtained when the height H is in the range of 20 to 30 mm.
[0009]
FIG. 4 shows the calculation results of the main beam direction and the F / S obtained by changing the diameter D while setting the height H of the closed-end cylindrical reflector 3 to 25 mm. A relatively large F / S can be obtained when the diameter D is in the range of 90 to 120 mm.
[0010]
【The invention's effect】
As described above, according to the present invention, the two dipole antennas 1 and 1 ′ driven in the same shape and different in phase but at the same amplitude and at the same amplitude are driven with the phase advanced by 60 °. By adopting a configuration in which the dipole antenna 1 ′ is arranged in a line on the Z-axis with the lower side facing down, and the closed-end cylindrical reflector 3 is arranged below the two dipole antennas 1 and 1 ′, The main radiation beam is directed in directions of about + 80 ° and about −80 ° with respect to the Z axis from the two dipole antennas 1 and 1 ′, and has a suppressed radiation pattern within a range of ± 40 ° with respect to the Z axis. That is, the directivity of the antenna is directed to the edge of the service area of the mobile phone, and a radiation pattern in which a radiation beam in the vicinity of the antenna is suppressed is generated. This makes it possible to average the signal reception strength in the service area of the mobile phone.
[Brief description of the drawings]
FIG. 1 illustrates an embodiment.
FIG. 2 is a diagram showing a directivity pattern according to the embodiment.
FIG. 3 is a diagram showing calculation results of a main beam direction and F / S of an example obtained by changing a height H.
FIG. 4 is a diagram showing main beam directions and F / S calculation results of an example obtained by changing a diameter D.
FIG. 5 is a diagram showing a directivity pattern of a conventional example.
[Explanation of symbols]
1, 1 'dipole antenna 2, 2' signal source 3 upper end closed cylindrical reflector 31 cylindrical reflector 32 disk reflector

Claims (1)

Two dipole antennas driven at the same amplitude with the same shape and different phases by 60 ° are arranged in a line on the Z-axis with the dipole antenna driven with the phase advanced by 60 ° on the lower side. A disk reflector is fixedly connected to the open upper end of the cylindrical reflector, and an integrated upper end closed cylindrical reflector is disposed below the two dipole antennas. Dipole antenna.

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