JP2008098993A - Antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna capable of achieving miniaturization and reducing the cost as well as obtaining preferable characteristics. <P>SOLUTION: The antenna 101 comprises: a dielectric 3; a first dipole antenna 1 arranged in the dielectric 3; a second dipole antenna 2 arranged in the dielectric 3 and arranged so as to be substantially orthogonal to the first dipole antenna 1; a feeding terminal 5; and a phase adjusting part 4 arranged in the dielectric 3 and generating a phase difference of substantially 90 degrees between a signal output from the first dipole antenna 1 to the feeding terminal 5 and a signal output from the second dipole antenna 2 to the feeding terminal 5 and/or between a signal output from the feeding terminal 5 to the first dipole antenna 1 and a signal from the feeding terminal 5 to the second dipole antenna 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an antenna device, and more particularly to an antenna device including a plurality of dipole antennas.

  In terrestrial digital broadcasting, since communication is performed with a guard interval, it is resistant to multipath interference, and a reflected wave can be received if a certain condition is satisfied. Therefore, development of an omnidirectional antenna for receiving horizontally polarized waves, such as UHF (Ultra High Frequency) television broadcasting compatible with terrestrial digital broadcasting, has been underway.

Here, conventionally, a turn-style antenna is known as a typical omnidirectional antenna (for example, see Non-Patent Document 1). The turn-style antenna obtains omnidirectionality by exciting two sets of orthogonal half-wave dipole antennas with a phase difference of 90 degrees. In the turn style antenna, a phase difference of 90 degrees is realized by using a phase line having a quarter wavelength of a radio wave (radio signal) to be transmitted or received. An example of a dipole antenna that receives radio waves of UHF television broadcasting is disclosed in Patent Document 1.
JP 2006-157209 A The Institute of Electronics, Information and Communication Engineers, “Antenna Engineering Handbook”, Ohmsha, October 1980, p. 412-413

  However, since the turn-style antenna uses a fixed-length phase line, the frequency band in which good transmission / reception characteristics can be obtained is narrow. Further, for example, in order to receive a 620 MHz radio wave in the frequency band of UHF television broadcasting, a phase line of about 10 cm is required, so that the antenna becomes large.

  Here, a coupler line is known as a phase shifter that generates a phase difference of 90 degrees between two signals. However, the coupler line is difficult to process and is expensive.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an antenna device that can achieve good characteristics and can be reduced in size and price.

  In order to solve the above problems, an antenna device according to an aspect of the present invention includes a dielectric, a first dipole antenna disposed on the dielectric, and a first dipole antenna disposed on the dielectric. A second dipole antenna arranged so as to be substantially orthogonal, a feed terminal, a signal placed on the dielectric, and output from the first dipole antenna to the feed terminal and output from the second dipole antenna to the feed terminal And / or a phase difference of approximately 90 degrees between the signal output from the feed terminal to the first dipole antenna and the signal output from the feed terminal to the second dipole antenna. A phase adjustment unit.

  Preferably, the phase adjustment unit is disposed at an intersection of the first dipole antenna and the second dipole antenna.

  Preferably, the phase adjusting unit has a first end coupled to the first dipole antenna, a second end coupled to the second dipole antenna, and a first end coupled to the feed terminal. , A second conductor line having a second end coupled to a predetermined potential, and a ground plane, wherein the first conductor line and the second conductor line are aligned with a predetermined length or more within a predetermined interval. It is fixed to.

  Preferably, each of the first dipole antenna and the second dipole antenna includes a first antenna element and a second antenna element that are symmetrical to each other with respect to the first axis, and the first antenna element and the second antenna element Each of the two antenna elements includes a first side and a second side away from the first axis so as to be separated from each other, and an end portion of the first side whose first end is far from the first axis. Is connected to the third side moving away from the first axis in a direction perpendicular to the first axis, and the first end is connected to the end of the second side farther from the first axis, A fourth side moving away from the first axis in a direction perpendicular to the first axis, an end of the first side closer to the first axis, and a side closer to the first axis A fifth side connecting the end of the second side, a second end of the third side, and a sixth side connecting the second end of the fourth side, Each of the ipole antenna and the second dipole antenna is further arranged along the first side and the third side, and a third conductor whose end is connected to the second end of the third side A line and a fourth conductor line that is disposed along the second side and the fourth side, and whose end is connected to the second end of the fourth side.

  According to the present invention, it is possible to achieve good characteristics and to reduce the size and the price.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of an antenna device according to an embodiment of the present invention.

  Referring to FIG. 1, antenna device 101 includes dipole antennas 1 and 2, a dielectric substrate 3, a phase adjustment unit 4, and a feed terminal 5. Dipole antenna 1 includes antenna elements 11 and 12. Dipole antenna 2 includes antenna elements 13 and 14. The antenna device 101 may be configured to include a dielectric film instead of the dielectric substrate 1.

  The antenna device 101 is, for example, a cross-dipole antenna that transmits or receives horizontally polarized waves of UHF television broadcast waves and has omnidirectionality.

  The dipole antenna 1 is disposed on the dielectric substrate 3. The dipole antenna 2 is disposed on the dielectric substrate 3 so as to be substantially orthogonal to the dipole antenna 1.

  The phase adjusting unit 4 is disposed on the dielectric substrate 3 at a portion where the dipole antennas 1 and 2 intersect. The phase adjustment unit 4 generates a phase difference of approximately 90 degrees between the received signals of the dipole antennas 1 and 2. Further, the phase adjustment unit 4 generates a phase difference of approximately 90 degrees between the transmission signals of the dipole antennas 1 and 2. More specifically, the phase adjustment unit 4 generates a phase difference of approximately 90 degrees between the signal output from the dipole antenna 1 to the power supply terminal 5 and the signal output from the dipole antenna 2 to the power supply terminal 5. Further, the phase adjustment unit 4 generates a phase difference of approximately 90 degrees between a signal output from the power supply terminal 5 to the dipole antenna 1 and a signal output from the power supply terminal 5 to the dipole antenna 2. The phase adjustment unit 4 may be configured to cause a phase difference of approximately 90 degrees between the reception signals of the dipole antennas 1 and 2 or between the transmission signals.

  FIG. 2 is a diagram illustrating a configuration of the phase adjustment unit 4. FIG. 3 is a diagram illustrating a circuit configuration of the phase adjustment unit 4.

  2 and 3, the phase adjustment unit 4 includes a conductor line (first conductor line) 31, a conductor line (second conductor line) 32, matching units 33 and 34, a substrate 35, and the like. The phase shifter 40 and the resistor R are included. Here, the power supply terminal 5 is disposed on the substrate 35 of the phase adjustment unit 4, for example.

  The conductor line 31 has a first end coupled to the dipole antenna 1 through the matching unit 33 and a second end coupled to the dipole antenna 2 through the matching unit 34. More specifically, the first terminal of the matching unit 33 is connected to the antenna element 11, the second terminal is connected to the antenna element 12, the third terminal is connected to the first end of the conductor line 31, and the fourth terminal is Connected to ground potential. The first terminal of the matching unit 34 is connected to the antenna element 13, the second terminal is connected to the antenna element 14, the third terminal is connected to the second end of the conductor line 31, and the fourth terminal is connected to the ground potential. The

The substrate 35 is an epoxy substrate having a thickness of 1.6 mm, for example.
The resistor R is a terminating resistor, and has a resistance value of, for example, 75Ω or 50Ω corresponding to the characteristic impedance of the phase shifter 40 or the like.

  The conductor line 32 has a first end coupled to the power supply terminal 5 and a second end coupled to the ground potential via the resistor R.

  In the phase shifter 40, the conductor lines 31 and 32 are fixed to the ground plane of the substrate 35 in a state where they are aligned for a predetermined length within a predetermined interval. More specifically, for example, the substrate 35 has insertion holes H1 to H10 arranged in a rectangular shape. The insertion holes H1, H3, H5, H7, H9 are arranged in a row at intervals of 2 mm, and the insertion holes H2, H4, H6, H8, H10 are arranged in a row at intervals of 2 mm in parallel with these. The distance between the row constituted by the insertion holes H1, H3, H5, H7, and H9 and the row constituted by the insertion holes H2, H4, H6, H8, and H10 is 6 mm. Conductor lines 31 and 32 are polyurethane wires having a diameter of 0.23 mm, for example. The conductor lines 31 and 32 are wound around the ground surface of the substrate 35 through the insertion holes H1 to H10 in a state of being in close contact with each other.

  Corner portions 36 to 39 of the substrate 35 are part of the ground contact surface of the phase adjustment unit 4. The corner portions 36 to 39 are coupled to conductor lines 23A to 23D described later of the dipole antennas 1 and 2.

  Matching units 33 and 34 perform impedance matching and balance-unbalance conversion between the dipole antenna side circuit and the phaser side circuit.

  In the phase adjustment unit 4, the dielectric constant of the substrate 35, the thickness of the substrate 35, and the lengths and thicknesses of the conductor lines 31 and 32 are adjusted so that the input / output signal of the phase adjustment unit 4 is 90 degrees. A phase difference can be given stably.

  The phase shifter 40 is configured using a known coupler line principle. That is, with respect to the signal output from the dipole antenna 1 through the phase shifter 40 to the power supply terminal 5, the signal output from the dipole antenna 2 through the phase shifter 40 to the power supply terminal 5 has a phase difference of 90 degrees. Occurs. Further, a signal output from the power supply terminal 5 through the phase shifter 40 to the dipole antenna 1 is output from the power supply terminal 5 through the phase shifter 40 and output to the dipole antenna 2 with a phase difference of 90 degrees. Occurs.

  The phase shifter 40 can be reduced in size as compared with a hybrid phase shifter using a conventional coupler line by adopting a configuration in which the conductor lines 31 and 32 are wound around the ground plane of the substrate 35. Further, the phase shifter 40 can be manufactured at a lower cost than a conventional hybrid phase shifter using a coupler line.

FIG. 4 is a diagram illustrating a configuration of a modification of the phase adjustment unit 4.
Referring to FIG. 4, phase shifter 40 has notches H11 and H12. For example, the conductor lines 31 and 32 are wound around the ground plane of the substrate 35 alternately passing through the protrusions of the notch H11 and the protrusions of the notch H12 in close contact with each other. Even with such a configuration, the phase shifter 40 can be reduced in size as compared with a conventional hybrid phase shifter using a coupler line, and can be manufactured at a low cost.

  FIG. 5 is a diagram illustrating a configuration of the dipole antenna 1. Since the configuration of dipole antenna 2 is the same as that of dipole antenna 1, detailed description will not be repeated here.

  Referring to FIG. 5, dipole antenna 1 includes antenna elements 11 and 12, conductor lines (third conductor lines) 23A and 23C, and conductor lines (fourth conductor lines) 23B and 23D. Hereinafter, the conductor lines 23A to 23D may be collectively referred to as the conductor line 23. The configuration of antenna element 12 and conductor lines 23C and 23D is the same as that of antenna element 11 and conductor lines 23A and 23B. Therefore, detailed description thereof will not be repeated here.

  The X axis and the Y axis are axes orthogonal to each other. The antenna elements 11 and 12 are symmetric with respect to the Y axis. Each of the antenna elements 11 and 12 has a symmetrical shape with respect to the X axis. The antenna element 11 has sides (first side to sixth side) 21A to 21F and 21G.

  The feeding point 24 of the antenna element 11 is disposed on the X axis and is connected to a matching unit in the phase adjustment unit 4.

  The side 21E is parallel to the Y axis. The side 21A has a first end connected to a first end of the side 21E. Further, the side 21B has a first end connected to a second end of the side 21E. The side 21A and the side 21B are away from the Y axis so as to be separated from each other.

  The side 21C has a first end connected to the second end of the side 21A and moves away from the Y axis in a direction parallel to the X axis. The side 21D has a first end connected to the second end of the side 21B and moves away from the Y axis in a direction parallel to the X axis. The side 21F connects the second end of the side 21C and the second end of the side 21D.

  The conductor lines 23A and 23B are for impedance matching. The conductor lines 23A and 23B are respectively arranged on both sides of the X axis.

  The conductor line 23A is disposed along the side 21A and the side 21C, and the first end is connected to the second end of the side 21C. The conductor line 23B is arranged along the side 21B and the side 21D, and the first end is connected to the second end of the side 21D.

  The conductor lines 23A and 23B are symmetric with respect to the X axis. Each of the conductor lines 23A and 23B is connected to the second end of the conductor line 23 in the other dipole antenna.

  With the configuration as described above, the dipole antenna 1 can realize a good gain in a wide frequency range and can realize an 8-shaped loop-shaped directivity pattern.

  As a result of the conductor lines 23A and 23B being arranged at a predetermined distance from the antenna element 11, slits 22A and 22B are formed between the antenna element 11 and the conductor lines 23A and 23B, respectively.

  FIG. 6 is a graph showing the loss characteristics of the phase shifter 40 according to the embodiment of the present invention. In FIG. 6, a graph G <b> 1 shows a transmission loss of a signal output from the power supply terminal 5 through the phase shifter 40 and output to the matching unit 33. The graph G2 shows the transmission loss of the signal output from the power supply terminal 5 through the phase shifter 40 to the matching unit 34.

  Referring to FIG. 6, phase shifter 40 achieves substantially uniform loss characteristics in the UHF band of 470 MHz to 770 MHz.

  FIG. 7 is a graph showing the phase characteristics of the phase shifter 40 according to the embodiment of the present invention. The graph G3 in FIG. 7 shows the phase of the signal output from the matching unit 34 through the phase shifter 40 to the power feeding terminal 5 with respect to the signal output from the matching unit 33 through the phase shifter 40 to the power feeding terminal 5. Show.

  Referring to FIG. 7, antenna apparatus 101 realizes a uniform phase difference of approximately 90 degrees in the UHF band of 470 MHz to 770 MHz.

  FIGS. 8A to 8F are diagrams showing directivity patterns of the antenna device according to the embodiment of the present invention with respect to horizontal polarizations of 470 MHz, 530 MHz, 590 MHz, 650 MHz, 710 MHz, and 770 MHz, respectively.

  With reference to FIGS. 8A to 8F, the antenna device 101 realizes a good omnidirectional pattern with respect to horizontal polarization in the UHF band of 470 MHz to 770 MHz.

  FIG. 9 is a graph showing gain characteristics and VSWR characteristics of the antenna device according to the embodiment of the present invention. In FIG. 9, a graph G4 indicates a gain, and a graph G5 indicates a VSWR (Voltage Standing Wave Ratio).

  Referring to FIG. 9, it can be seen from graph G4 that antenna device 101 achieves a substantially uniform gain in the UHF band of 470 MHz to 770 MHz.

  Further, it can be seen from the graph G5 that the antenna device 101 realizes a substantially uniform VSWR in the 470 MHz to 770 MHz UHF band.

  6 to 9, it can be seen that the antenna device according to the embodiment of the present invention achieves good transmission / reception characteristics in the entire UHF band. Note that the antenna device according to the embodiment of the present invention can realize good transmission / reception characteristics not only in the UHF band but also in other frequency bands.

  By the way, since the turn-style antenna uses a fixed-length phase line, the frequency band in which good transmission / reception characteristics can be obtained is narrow. And depending on the frequency of the radio wave to be transmitted and received, the phase line becomes long and the antenna becomes large. Further, when a coupler line is used as the phase shifter, the coupler line is difficult to process and is expensive. However, in the antenna device according to the embodiment of the present invention, dipole antennas 1 and 2 are arranged on dielectric substrate 3 so as to be substantially orthogonal to each other, and at least one of transmission signals and reception signals of dipole antennas 1 and 2 is used. A phase adjusting unit 4 that causes a phase difference of 90 degrees is disposed on the dielectric substrate 3. With such a configuration, an omnidirectional antenna having good transmission / reception characteristics can be realized, and a reduction in size and weight and a reduction in price can be achieved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a figure which shows the structure of the antenna device which concerns on embodiment of this invention. FIG. 4 is a diagram illustrating a configuration of a phase adjustment unit 4. 3 is a diagram illustrating a circuit configuration of a phase adjustment unit 4. FIG. FIG. 6 is a diagram illustrating a configuration of a modification of the phase adjustment unit 4. 1 is a diagram illustrating a configuration of a dipole antenna 1. FIG. It is a graph which shows the loss characteristic of the phase shifter 40 which concerns on embodiment of this invention. It is a graph which shows the phase characteristic of the phase shifter 40 which concerns on embodiment of this invention. (A)-(f) is a figure which shows the directivity pattern of the antenna apparatus which concerns on embodiment of this invention with respect to the horizontal polarization of 470 MHz, 530 MHz, 590 MHz, 650 MHz, 710 MHz, and 770 MHz, respectively. It is a graph which shows the gain characteristic and VSWR characteristic of the antenna device which concern on embodiment of this invention.

Explanation of symbols

  1, 2 Dipole antenna, 3 Dielectric substrate, 4 Phase adjustment unit, 5 Feeding terminal, 11, 12 Antenna element, 21A to 21F Side (first side to sixth side), 21G side, 23 Conductor line, 23A , 23C Conductor line (third conductor line), 23B, 23D Conductor line (fourth conductor line), 31, 32 Conductor line, 33, 34 Matching device, 35 Substrate, 40 Phaser, 101 Antenna device, R resistance , H11, H12 Notch.

Claims (4)

A dielectric,
A first dipole antenna disposed on the dielectric;
A second dipole antenna disposed on the dielectric and disposed substantially orthogonal to the first dipole antenna;
A power supply terminal;
Between the signal output from the first dipole antenna to the power supply terminal and the signal output from the second dipole antenna to the power supply terminal and / or from the power supply terminal. An antenna apparatus comprising: a phase adjusting unit that generates a phase difference of approximately 90 degrees between a signal output to the first dipole antenna and a signal output from the power supply terminal to the second dipole antenna.   The antenna device according to claim 1, wherein the phase adjustment unit is disposed at an intersection of the first dipole antenna and the second dipole antenna. The phase adjusting unit is
A first conductor line having a first end coupled to the first dipole antenna and a second end coupled to the second dipole antenna;
A second conductor line having a first end coupled to the power supply terminal and a second end coupled to a predetermined potential;
Including a ground plane,
2. The antenna device according to claim 1, wherein the first conductor line and the second conductor line are fixed to the ground plane in a state where the first conductor line and the second conductor line are arranged in a predetermined length within a predetermined interval. Each of the first dipole antenna and the second dipole antenna is
Comprising a first antenna element and a second antenna element that are symmetrical with respect to a first axis;
Each of the first antenna element and the second antenna element is:
A first side and a second side moving away from the first axis so as to be separated from each other;
A first side connected to an end of the first side farther from the first axis, and a third side moving away from the first axis in a direction perpendicular to the first axis;
A first end connected to an end of the second side farther from the first axis, and a fourth side away from the first axis in a direction perpendicular to the first axis;
A fifth side connecting the end of the first side closer to the first axis and the end of the second side closer to the first axis;
A sixth side connecting the second end of the third side and the second end of the fourth side;
Each of the first dipole antenna and the second dipole antenna further comprises:
A third conductor line disposed along the first side and the third side and having an end connected to the second end of the third side;
The antenna device according to claim 1, further comprising: a fourth conductor line disposed along the second side and the fourth side and having an end connected to a second end of the fourth side.

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