JP4268096B2 - Balun device and antenna device - Google Patents

Description

  The present invention relates to a balun device that performs line conversion between an unbalanced feed line and a balanced feed line, an antenna device such as a dipole antenna or a Yagi-Uda antenna using the balun device, and an antenna device formed on a substrate About.

  An antenna used for a wireless LAN system or Bluetooth is required to have a design that can be produced at low cost. As a commonly used antenna, there is a `` dielectric antenna '' with a high dielectric as a component, but mainly because miniaturization is important, compared with antennas made of metal plates such as copper, Many have low gain and poor performance. In addition, the dielectric antenna uses a ceramic having a very high dielectric constant as its material, and its performance is greatly affected by environmental changes that affect the dielectric constant. For example, when it is actually used in a product, the influence of the housing must be taken into consideration, and the antenna arrangement must be studied, designed and adjusted.

  In order to solve these problems, the technology of pattern antennas printed on the substrate has been widespread, but since many of the pattern antennas in general use need to connect a coaxial cable, Is formed by a conductor pattern, and the conductor pattern of the antenna is formed on one side of the substrate.

JP-A-6-188610.

  For example, FIG. 4B of Patent Document 1 discloses a printed circuit board balun for converting a coaxial cable that is an unbalanced feed line into a balanced feed line. The printed circuit board balun according to this prior art is designed based on a branch conductor type balun having a length of ¼λ (λ is the wavelength of a radio signal to be transmitted) as shown in FIG. Therefore, it is necessary to print the balun on both sides of the printed board, and the influence of the board thickness must be fully taken into consideration. In FIG. 9, the coaxial cable 41 is connected to a dipole antenna 42 composed of two antenna elements 42 a and 42 b, and the core conductor 41 a of the coaxial cable 41 is connected to the antenna side end portion of the coaxial cable 43 for branching conductors by the connecting conductor 44. While being connected to the core wire conductor 43 a and the ground conductor 43 b, the ground conductor 41 b of the coaxial cable 43 is connected to the open-end-side ground conductor 43 b of the coaxial cable 43 by the connecting conductor 45.

  In FIG. 10, in the case of applying a branched conductor type balun to a dipole antenna 52 composed of two antenna elements 52a and 52b formed on one surface of the printed wiring board 50, FIG. 2, the ground conductor 41 b of the coaxial cable 41 is fixed so as to be connected along the branch conductors 53 connected to the center ends of the antenna elements 52 a and 52 b, and the coaxial cable 41 is The core wire conductor 41a needs to be connected to the end portion of the branch conductor 53 on the antenna 52b side by the connecting conductor 44.

  In the conventional example of FIG. 10, the branch conductor 53 is formed without using the coaxial cable 43 of FIG. 9, and thus impedance matching between the coaxial cable 41 and the dipole antenna 52 is not performed. Since the influence of the routing of the core wire conductor 41a must be taken into consideration sufficiently, it cannot be said to be practical.

  Furthermore, as described above, the conductor pattern of the antenna element is formed on one side of the printed wiring board, but when the board thickness is a thick board of, for example, 1 mm or more, the radiation of electromagnetic waves toward the back side of the board is There is a problem in that the antenna gain decreases due to attenuation.

  The first object of the present invention is to solve the above-mentioned problems, and in a balun device that performs line conversion between an unbalanced feed line and a balanced feed line, it is smaller and lighter than the prior art and is on a dielectric substrate. Another object of the present invention is to provide a balun device that can be formed easily and that can perform impedance matching with certainty, and an antenna device using the balun device.

  In addition, the second object of the present invention is to solve the above-described problems, and even when an antenna is formed on a substrate, radiation of electromagnetic waves toward the back surface of the substrate is attenuated and antenna gain is reduced. An object of the present invention is to provide an antenna device without the above.

A balun device according to a first aspect of the present invention is a strip-shaped core conductor formed on a substrate and having an unbalanced end and a balanced end,
The strip-shaped first and second strips are formed on both sides of the core conductor so as to be spaced apart from the core conductor by a predetermined distance on the substrate, and have unbalanced side ends and balanced side ends, respectively. A ground conductor;
On the substrate, extending from the balanced end of each ground conductor and bent to the opposite side of the core conductor, the end becomes an open end, and is separated from each connection conductor by a predetermined distance. Strip-shaped first and second folded conductors formed so as to
The unbalanced end of the first ground conductor and the unbalanced end of the second ground conductor are connected to each other to become an unbalanced ground terminal, and the unbalanced end of the core conductor is unbalanced. It becomes a balanced core wire terminal,
The balanced end of the core conductor is a first balanced connection terminal, and the balanced end of the second ground conductor is a second balanced connection terminal.

  In the balun device, the core conductor, the first and second ground conductors, and the first and second folded conductors are substantially an odd multiple of 1/4 of the wavelength of the radio signal to be transmitted. It has a length.

An antenna device according to a second invention includes the balun device,
A dipole antenna comprising two first antenna elements formed on a straight line and spaced apart from each other by a predetermined distance and connected to the first and second balanced connection terminals of the balun device It is characterized by comprising.

  In the antenna device, the core wire conductor, the first and second connection conductors, and the first and second folded conductors of the balun device are inclined with respect to the two first antenna elements, or It is formed to be vertical.

In the antenna device, the substrate has first and second surfaces substantially parallel to each other,
The two first antenna elements are respectively
A first element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the first element conductor and through both ends of the first element conductor in the thickness direction. And a second element conductor having both ends connected via a hole conductor.

  The antenna apparatus further includes a reflective antenna element that is formed of a second antenna element that is parallel to the dipole antenna and spaced apart from the dipole antenna by a predetermined distance, and has a longer length than the dipole antenna. Features.

In the antenna device, the substrate has first and second surfaces substantially parallel to each other,
The second antenna element is
A third element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the third element conductor and through both ends of the third element conductor in the thickness direction. And a fourth element conductor having both ends connected via a hole conductor.

  The antenna apparatus further includes a third antenna element that is parallel to the dipole antenna and spaced apart by a predetermined distance, and further includes a waveguide antenna element having a shorter length than the dipole antenna. It is characterized by that.

Still further, in the antenna device, the substrate has first and second surfaces substantially parallel to each other,
The third antenna element is
A fifth element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the fifth element conductor, and formed at both ends of the fifth element conductor and penetrating the substrate in the thickness direction. And a sixth element conductor having both ends connected via a hole conductor.

In the antenna device, the other balun device,
It consists of two fourth antenna elements formed on a straight line and spaced apart from each other by a predetermined distance, and connected to the first and second balanced connection terminals of the other balun device. It is provided with another dipole antenna.

  In the antenna device, the core wire conductor, the first and second connection conductors, and the first and second folded conductors of the other balun device are inclined with respect to the two fourth antenna elements. Or formed so as to be vertical.

Further, in the antenna device, the substrate has first and second surfaces substantially parallel to each other,
Each of the two fourth antenna elements is
A seventh element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the seventh element conductor, and formed so as to penetrate both ends of the seventh element conductor in the thickness direction. And an eighth element conductor having both ends connected via a hole conductor.

  Still further, in the antenna device, the first unbalanced line connected to the unbalanced core wire terminal and the unbalanced ground terminal of the balun device, and the unbalanced core wire terminal and the unbalanced side of the other balun device. It further comprises switching means for selectively switching the second unbalanced line connected to the ground terminal to connect to the radio.

An antenna device according to a third invention comprises a substrate having first and second surfaces substantially parallel to each other;
A first element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the first element conductor and through both ends of the first element conductor in the thickness direction. A second element conductor having both ends connected via a hole conductor,
One end of the first and second element conductors is an open end, and the other end of the first and second element conductors is a feeding end.

An antenna device according to a fourth invention comprises a substrate having first and second surfaces substantially parallel to each other;
A dipole antenna comprising two first antenna elements formed on a straight line and spaced apart from each other by a predetermined distance;
The two first antenna elements are respectively
A first element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the first element conductor and through both ends of the first element conductor in the thickness direction. And a second element conductor having both ends connected via a hole conductor.

  The antenna apparatus further includes a reflective antenna element that is formed of a second antenna element that is parallel to the dipole antenna and spaced apart from the dipole antenna by a predetermined distance, and has a longer length than the dipole antenna. Features.

In the antenna device, the second antenna element is
A third element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the third element conductor and through both ends of the third element conductor in the thickness direction. And a fourth element conductor having both ends connected via a hole conductor.

  The antenna apparatus further includes a third antenna element that is parallel to the dipole antenna and spaced apart by a predetermined distance, and further includes a waveguide antenna element having a shorter length than the dipole antenna. It is characterized by that.

Furthermore, in the antenna device, the third antenna element is
A fifth element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the fifth element conductor, and formed at both ends of the fifth element conductor and penetrating the substrate in the thickness direction. And a sixth element conductor having both ends connected via a hole conductor.

Still further, in the antenna device, the antenna device includes two fourth antenna elements formed on a straight line and spaced apart from each other by a predetermined distance. With another dipole antenna connected to the balanced side connection terminal,
Each of the two fourth antenna elements is
A seventh element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the seventh element conductor, and formed so as to penetrate both ends of the seventh element conductor in the thickness direction. And an eighth element conductor having both ends connected via a hole conductor.

  Therefore, according to the balun device according to the present invention, the balun device can be formed by forming a conductor pattern with a thickness similar to the thickness on a printed wiring board or the like. The balun device is a balun device that performs line conversion between an unbalanced feed line and a balanced feed line, and is smaller and lighter than the prior art, can be formed on a substrate, and can reliably perform impedance matching. it can.

  Moreover, according to the antenna device provided with the balun device according to the present invention, the antenna device provided with the balun device is formed by forming a conductor pattern with a thickness similar to the thickness on a substrate such as a printed wiring board. it can. The antenna device is smaller and lighter than the prior art, can be formed on a substrate, and can reliably perform impedance matching.

  Furthermore, according to the antenna device according to the present invention, since the radiating antenna elements are formed on both surfaces of the substrate, it is possible to radiate radio waves in the direction of the back surface of the substrate, and to prevent the antenna gain from being lowered.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component.

First embodiment.
FIG. 1 is a plan view showing the front surface of the two-element Yagi-Uda antenna device according to the first embodiment of the present invention, and FIG. 2 is a rear view showing the back surface of the two-element Yagi-Uda antenna device of FIG. is there. The two-element Yagi-Uda antenna device according to the first embodiment is configured to include a radiating antenna element A1 that is a dipole antenna and a reflecting antenna element A3 formed in parallel thereto, and is unbalanced with the radiating antenna element A1. A balun device B1 formed on the front surface of the dielectric substrate 10 which is a printed wiring board is inserted between the coaxial cable 20 which is a feeder line. Here, the balun device B1 is configured by forming, on the dielectric substrate 10, a conductor in a cross section that passes through the central axis of the coaxial cable 60 that constitutes the super top balun device 70 of FIG. It is characterized by. The balun B1 has a line conversion function and an impedance matching function between the coaxial cable 20 that is an unbalanced feed line and the radiation antenna element A1 that is a dipole antenna of a balanced antenna.

  1 and 2, a dielectric substrate 10 that is a parallel plate is a printed wiring board such as a glass epoxy board or a Teflon (registered trademark) board, and has a front surface and a back surface that are substantially parallel to each other. . On the front surface of the dielectric substrate 10, the balun device B1, the element conductors 1a and 2a of the radiating antenna element A1, and the element conductor 7a of the reflective antenna element A3 are formed using a printed wiring printing method. . On the other hand, the element conductors 1b and 2b of the radiating antenna element A1 and the element of the reflective antenna element A3 are arranged on the back surface of the dielectric substrate 10 so as to face the element conductors 1a, 2a, and 7a via the dielectric substrate 10, respectively. The conductor 7b is formed using a printed wiring printing method. The dielectric substrate 10 is provided with a plurality of mounting screw holes 15 penetrating in the thickness direction.

  In the radiating antenna element A1, the element conductors 1a, 2a, 1b and 2a have a strip shape having a length of substantially ¼ wavelength of the radiated radio wave, and the element conductors 1a and 2a are substantially straight. The element conductors 1b and 2b are formed substantially on a straight line. Also, through-holes that penetrate the dielectric substrate 10 in the thickness direction are formed at both ends of the element conductors 1a and 1b, and the through-hole conductors 11a and 11b are formed by filling the through-holes with conductors, respectively. Thus, the element conductors 1a and 1b are connected at both ends thereof. Furthermore, through-holes that penetrate the dielectric substrate 10 in the thickness direction are formed at both ends of the element conductors 2a and 2b, and the through-hole conductors 12a and 12b are formed by filling the through-holes with conductors, respectively. Thus, the element conductors 2a and 2b are connected at both ends thereof. The radiating antenna element A1 configured as described above forms a half-wave dipole antenna.

  The element conductor of the radiating antenna element A1 is formed not only on one side but also on both sides for the following reason. When formed on only one surface, for example, when the thickness of the dielectric substrate 10 which is a glass epoxy substrate is 1 mm, the radiated radio wave from the radiating antenna element A1 toward the back surface of the dielectric substrate 10 is attenuated by about 1 dB. Since the gain decreases, it is formed on both sides to prevent this.

  In the reflective antenna element A3, the element conductors 7a and 7b have a strip shape having a length slightly longer than ¼ wavelength, and are separated from the radiating antenna element A1 by, for example, an interval d1 of ¼ wavelength of the radiated radio wave. Formed. Also, through-holes penetrating the dielectric substrate 10 in the thickness direction are formed at both ends of the element conductors 7a and 7b, and the through-hole conductors 13a and 13b are formed by filling the through-holes with conductors, respectively. Thereby, the element conductors 7a and 7b are connected at both ends thereof. The reflection antenna element A3 configured as described above forms a reflector for the radiation antenna element A1. Therefore, the radiating antenna element A1 and the reflective antenna element A3 constitute a two-element Yagi-Uda antenna device.

  Next, the configuration of the balun device B1 will be described below. As described above, the balun device B1 has conductors in a cross section passing through the center of the coaxial cable 60 constituting the super-top balun device 70 of FIG. In consideration of the shortening rate of the substrate 10, it is slightly shorter than the quarter wavelength, but this is a design matter, and is shown as 1 / 4λ ′ in FIG. , 4 s, 5 s on the dielectric substrate 10. The strip-shaped conductors 3, 4, 5, 4s, 5s constituting the balun device B1 are formed so that the longitudinal direction thereof is inclined by about 60 degrees with respect to the longitudinal direction of the radiating antenna element A1. . This is to make the length in the horizontal direction of FIG. 1 occupied by the balun device B1 as short as possible, thereby reducing the overall size of the antenna device. In the first embodiment, the balun device B1 is formed so as to be inclined with respect to the radiating antenna element A1, but the present invention is not limited thereto, and the balun device B1 is not inclined but is in a substantially vertical direction. You may form as follows.

  The core wire conductor 3 of the balun device B1 is formed so as to be connected to and extend from the end (on the balanced side) of the element conductor 1a on the through-hole conductor 11b side. The terminal conductor 3t is connected and formed, and the end becomes an unbalanced end. Further, a rectangular ground terminal conductor 6 is formed at a predetermined distance from the core wire terminal conductor 3t in the longitudinal direction of the core wire conductor 3. Further, ground conductors 4 s and 5 s are formed on both sides of the core conductor 3 (on the outside as viewed from the core conductor 3, hereinafter referred to as the outside) so as to be separated by a predetermined distance and parallel to the core conductor 3. The The end of the grounding conductor 4s on the side of the radiating antenna element A1 is, for example, curved and bent 180 degrees outward in a direction away from the core conductor 3, and extends so as to be parallel to the grounding conductor 4s to form the folded conductor 4. On the other hand, the other end of the ground conductor 4s extends in the longitudinal direction of the ground conductor 4s and is connected to the ground terminal conductor 6, and the other end is an unbalanced end. The end of the grounding conductor 5s on the side of the radiating antenna element A1 is, for example, curved and bent outward 180 degrees in a direction away from the core conductor 3, and extends so as to be parallel to the grounding conductor 5s. On the other hand, the other end portion of the ground conductor 5s extends in the longitudinal direction of the ground conductor 5s and is connected to the ground terminal conductor 6, and the other end portion is an unbalanced end portion. The end of the ground conductor 5s on the side of the radiating antenna element A1 (the end on the balanced side) is connected to one end of the connection conductor 8 formed on the back surface of the dielectric substrate 10 through the through-hole conductor 5a. The other end of the connection conductor 8 is connected to the end of the element conductor 2b on the through-hole conductor 12b side.

  A coaxial cable 20 serving as a feed line from a radio transceiver (not shown) is composed of a core wire conductor 21 and a ground conductor 22, and the core wire conductor 21 is electrically connected to the core wire terminal conductor 3t by soldering, for example. The ground conductor 22 is electrically connected to the ground terminal conductor 6 by soldering, for example. Although the coaxial cable 20 is an unbalanced line, the core wire terminal conductor 3t and the ground conductors 4s and 5s formed on both sides thereof, and the core wire conductor 3 and the ground conductors 4s and 5s formed on both sides thereof are respectively balanced lines. This constitutes a coplanar track. That is, line conversion from the coaxial cable 20 to the coplanar line is performed near the ground terminal conductor 3t. The folded conductors 4 and 5 are configured to have a length that is about ¼ times the wavelength of the radiated radio wave, and are folded to form a wiring with a certain distance from the ground conductors 4s and 5s, respectively. As shown in FIG. 8, the balun device B1 has an impedance matching function and a line conversion function in the same manner as the conventional super-balun device 70 of FIG. Have

  In the two-element Yagi-Uda antenna device including the balun device B1 configured as described above, a radio signal transmitted from the wireless transceiver via the coaxial cable 20 is transmitted from the unbalanced line to the balanced line by the balun device B1. After the line conversion to and the impedance matching between the coaxial cable 20 and the radiating antenna element A1, radio waves of the radio signal are radiated from the radiating antenna element A1. Here, since the element conductors 1a, 2a, 1b2b of the radiating antenna element A1 are formed on both surfaces of the dielectric substrate 10, they are also radiated from the back surface thereof. Further, since the reflective antenna element A3 which is a reflector is formed, the radio wave of the radio signal is in a direction perpendicular to the longitudinal direction of the radiating antenna element A1 and on the side opposite to the reflective antenna element A3. Radiated with the main beam towards.

  Since the balun device B1 configured as described above is formed of only the conductor of the printed wiring pattern on the dielectric substrate 10, the balun device 10 can be formed with substantially the same thickness as the dielectric substrate 10, and the conventional technology Compared to the small size and light weight, line conversion and impedance matching can be reliably performed.

Modification of the first embodiment.
In the above embodiment, a two-element Yagi-Uda antenna device including the radiating antenna element A1 and the reflecting antenna element A3 is configured. A wave guide that is opposite to the antenna element A3 and is spaced apart from the radiating antenna element A1 by about ¼ wavelength and has a length shorter than that of the radiating antenna element A1 and the same configuration as that of the reflecting antenna element A3. A three-element Yagi-Uda antenna device may be configured by forming an antenna element. Further, the number of reflectors and directors is not limited to one and may be plural. Furthermore, a half-wave dipole antenna device may be formed without forming the reflective antenna element A3.

  Moreover, you may comprise a monopole antenna apparatus using the antenna element of the said half-wavelength dipole antenna apparatus. In this case, the coaxial cable 20 can be directly connected to the monopole antenna device without using the balun device B1.

  In the above embodiment, the element conductors of the radiating antenna element A1 and the reflective antenna element A3 are formed on both surfaces of the dielectric substrate 10, but the present invention is not limited to this and may be formed only on one surface thereof. .

  In the above embodiment, the length of each conductor 3, 4, 5, 4s, 5s of the balun device B1 has a length of about ¼ wavelength, but the present invention is not limited to this, and (2n -1) / 4 wavelength (where n is a natural number) may be formed.

Second embodiment.
FIG. 3 is a plan view showing the front surface of the three-element Yagi-Uda antenna device according to the second embodiment of the present invention, and FIG. 4 is a rear view showing the back surface of the three-element Yagi-Uda antenna device of FIG. is there. 3 and 4, the three-element Yagi-Uda antenna device according to the second embodiment is a reflective antenna element A3 as compared to the two-element Yagi-Uda antenna device according to the first embodiment of FIGS. Is different from the radiating antenna element A1 in that the radiating antenna element A2 and the balun device B2 connected to the radiating antenna element A2 are further separated from the reflecting antenna element A3 by a predetermined distance d1. This difference will be described below.

  3 and 4, the radiating antenna element A2 is connected to the element conductors 101a and 101b whose both ends are connected by the through-hole conductors 111a and 111b and the both ends are connected by the through-hole conductors 112a and 112b, similarly to the radiating antenna element A1. The element conductors 102a and 102b are configured to operate in the same manner as the radiating antenna element A1, but the direction of the main beam of the radiated radio wave is opposite to that of the radiating antenna element A1.

  Similarly to the balun device B1, the balun device B2 extends from the core wire conductor 103, the ground conductors 104s and 105s formed on both sides thereof, and extends from the ground conductors 104s and 105s and is bent to be ground conductors 104s, The folded conductors 104 and 105 are formed so as to be parallel to 105 s, and have a line conversion function and an impedance matching function like the balun device B1. Here, the core conductor 3 is connected to the core terminal conductor 103t, and the ground conductors 4s and 5s are connected to the ground terminal conductor 106. A coaxial cable 120 serving as a power feed line from the wireless transceiver includes a core wire conductor 121 and a ground conductor 122. The core wire conductor 121 is electrically connected to the ground conductor 122 by a core wire terminal conductor 103t, for example, by soldering. Are electrically connected by a ground terminal conductor 106, for example, by soldering. Further, the end of the ground conductor 105s on the side of the radiating antenna element A3 is connected to one end of the connection conductor 108 formed on the back surface of the dielectric substrate 10 through the through-hole conductor 105a, and the other end of the connection conductor 108 is connected. Is connected to the end of the element conductor 102b on the through-hole conductor 112b side.

  FIG. 5 is a block diagram showing a configuration of a radio transceiver apparatus connected to the radiation antenna elements A1 and A3 of FIGS.

  In FIG. 5, the radiating antenna element A1 is connected to the circulator 81 through the contact a of the switch SW, and the radiating antenna element A3 is connected to the circulator 81 through the contact b of the switch SW. A radio signal received by the radiating antenna element A1 or A3 is input to the radio receiver circuit 82 via the switch SW and the circulator 81, and processing such as high-frequency amplification, frequency conversion, frequency amplification, and demodulation is performed. On the other hand, a radio signal transmitted from the radio transmitter circuit 83 is output and radiated to the radiating antenna element A1 or A3 via the circulator 81 and the switch SW. The controller 80 controls the operation of the radio receiver circuit 82 and the radio transmitter circuit 83. For example, the signal level of the radio signal received by the radiating antenna element A1 and the signal of the radio signal received by the radiating antenna element A3. The switch SW is switched so as to select the radiating antenna element that has received the higher signal level by comparing with the level, and radio signals are transmitted and received.

  The three-element Yagi-Uda antenna device provided with the balun devices B1 and B2 according to the second embodiment configured as described above is formed on the dielectric substrate 10 only with the conductor of the printed wiring pattern. It can be formed with substantially the same thickness as the body substrate 10, is smaller and lighter than the prior art, and line conversion and impedance matching can be reliably performed using the balun devices B1 and B2. Furthermore, radio signals can be transmitted and received by selectively switching between two radiating antenna elements A1 and A2 having different main beams in opposite directions.

Modified example of the second embodiment.
In the above embodiment, a three-element Yagi-Uda antenna device including two radiation antenna elements A1 and a reflection antenna element A3 is configured. However, the present invention is not limited to this, and the radiation antenna element A1 is the center. The opposite side of the reflective antenna element A3 is spaced from the radiating antenna element A1 by about ¼ wavelength and has a length shorter than that of the radiating antenna element A1, and the same configuration as that of the reflective antenna element A3. You may comprise a 5-element Yagi-Uda antenna apparatus by forming the antenna element of the waveguide which each has. Further, the number of reflectors and directors is not limited to one or two, but may be more than that. Furthermore, instead of forming the reflective antenna element A3, two dipole antenna devices may be formed to form a space diversity antenna element.

  In the above embodiment, the element conductors of the radiating antenna elements A1 and A2 and the reflective antenna element A3 are formed on both surfaces of the dielectric substrate 10, but the present invention is not limited to this, and is formed only on one surface thereof. Also good.

  In the above embodiment, the two radiating antenna elements A1 and A2 are formed so as to be parallel to each other, but the present invention is not limited to this, and may be formed so as not to be parallel. In this case, the beam direction or directivity is different.

  In the above embodiment, the reflective antenna element A3 is shared by the two radiating antenna elements A1 and A2, but the present invention is not limited to this, and a plurality of antenna devices of the first embodiment are formed, and For example, they may be formed on the dielectric substrate 10 so that the main beam directions are different from each other.

  The present inventors made a prototype of a dipole antenna device in which the reflective antenna element A3 is not formed in the first embodiment and the center operating frequency is 5.2 GHz, and performed the following experiment to obtain the result. .

  FIG. 6A is a characteristic diagram showing the horizontal plane directivity of the dipole antenna device according to the modification of the first embodiment, and FIG. 6B is the characteristic of the dipole antenna device according to the modification of the first embodiment. It is a characteristic view which shows a vertical surface directivity characteristic. As is apparent from FIG. 6, the directivity characteristics of a normal dipole antenna device can be obtained.

  FIG. 7 is a graph showing the frequency characteristic of the voltage standing wave ratio (VSWR) of the dipole antenna device provided with the balun device according to the modification of the first embodiment. As is apparent from FIG. 7, about 800 MHz is obtained as a frequency bandwidth with a central operating frequency of 5.2 GHz and a VSWR of 1.5 or less.

  Since the antenna device according to the embodiment or the modified example formed as described above can pattern a conductor with high accuracy by using a printed wiring printing method, the frequency characteristics and directivity characteristics can be obtained even in mass production. Very little variation. Further, even when the dielectric constant of the dielectric substrate 10 is slightly deviated, the radiation characteristics are hardly affected.

  In the above embodiment or modification, the dielectric substrate 10 is used. However, the present invention is not limited to this, and other types of substrates such as a semiconductor substrate or a dielectric film may be used.

  As described above, according to the balun device according to the present invention, the balun device can be formed by forming the conductor pattern with the same thickness as that of the printed circuit board on the substrate. The balun device is a balun device that performs line conversion between an unbalanced feed line and a balanced feed line, and is smaller and lighter than the prior art, can be formed on a substrate, and can reliably perform impedance matching. it can.

  Moreover, according to the antenna device provided with the balun device according to the present invention, the antenna device provided with the balun device is formed by forming a conductor pattern with a thickness similar to the thickness on a substrate such as a printed wiring board. it can. The antenna device is smaller and lighter than the prior art, can be formed on a substrate, and can reliably perform impedance matching.

  Furthermore, according to the antenna device according to the present invention, since the radiating antenna elements are formed on both surfaces of the substrate, it is possible to radiate radio waves in the direction of the back surface of the substrate, and to prevent the antenna gain from being lowered.

  As described above, by using a pattern antenna with a built-in balun, not only can it be mounted on a normal electric circuit board such as a glass epoxy board or a Teflon (registered trademark) board, but it can also be printed in film form, It can be applied directly to the body with a paint containing metal. Manufacturing at a low cost can be easily performed, and at the same time, the influence of the dielectric constant of the material constituting the conductor pattern is small, so that the arrangement of the antenna in the product or the like is relatively unproblematic. In addition, since it is possible to easily provide directivity by arranging a parasitic element pattern, the usage application is wide, for example, when radiation in an arbitrary direction is desired. For example, the present invention can be used for all home appliances using wireless LAN systems and Bluetooth, and other devices using wireless communication.

It is a top view which shows the front surface of the 2 element Yagi-Uda antenna device which concerns on the 1st Embodiment of this invention. It is a back view which shows the back surface of the 2 element Yagi-Uda antenna apparatus of FIG. It is a top view which shows the front surface of the 3 element Yagi-Uda antenna device which concerns on the 2nd Embodiment of this invention. It is a back view which shows the back surface of the 3 element Yagi-Uda antenna apparatus of FIG. FIG. 5 is a block diagram showing a configuration of a radio transceiver apparatus connected to the radiation antenna elements A1 and A3 of FIGS. 3 and 4. (A) is a characteristic view which shows the horizontal plane directivity of the dipole antenna device which concerns on the modification of 1st Embodiment, (b) is the perpendicular | vertical plane directivity of the dipole antenna apparatus which concerns on the modification of 1st Embodiment. FIG. It is a graph which shows the frequency characteristic of the voltage standing wave ratio (VSWR) of the dipole antenna apparatus provided with the balun apparatus which concerns on the modification of 1st Embodiment. It is a perspective view which shows the external appearance of the supper top balun apparatus 70 which is a prototype of balun apparatus B1, B2 which concerns on 1st and 2nd embodiment. It is a perspective view which shows the structure of the branch conductor type balun apparatus which concerns on a 1st prior art example. It is a perspective view which shows the structure of the branch conductor type balun apparatus which concerns on a 2nd prior art example.

Explanation of symbols

A1, A2 ... Radiating antenna elements,
A3: Reflective antenna element,
B1, B2 ... Balun device,
SW ... switch,
1a, 1b, 2a, 2b, 7a, 7b, 101a, 101b, 102a, 102b ... element conductors,
3,130 ... core conductor,
3t, 103t ... core wire terminal conductor,
4, 5, 104, 105 ... folded conductor,
4a, 5s, 104s, 105s ... grounding conductor,
5a, 11a, 11b, 12a, 12b, 13a, 13b, 105a, 111a, 111b, 112a, 112b ... through-hole conductors,
6 ... Ground terminal conductor,
8: Connection conductor,
10 ... dielectric substrate,
15 ... Hole for mounting screw,
20, 120 ... Coaxial cable,
21, 121 ... core wire conductor,
22, 122 ... ground conductor,
80 ... Controller,
81 ... circulator,
82 ... wireless receiver circuit,
83: Radio transmitter circuit.

Claims (12)

A strip-shaped core conductor formed on a substrate and having an unbalanced end and a balanced end;
The strip-shaped first and second strips are formed on both sides of the core conductor so as to be spaced apart from the core conductor by a predetermined distance on the substrate, and have unbalanced side ends and balanced side ends, respectively. A ground conductor;
On the substrate, extending from the balanced end of each ground conductor and bent to the opposite side of the core conductor, the end becomes an open end, and is separated from each connection conductor by a predetermined distance. Strip-shaped first and second folded conductors formed so as to
The unbalanced end of the first ground conductor and the unbalanced end of the second ground conductor are connected to each other to become an unbalanced ground terminal, and the unbalanced end of the core conductor is unbalanced. It becomes a balanced core wire terminal,
Balanced side end portion of the core conductor becomes first balanced-side connection terminal, the balanced-side end of the second grounding conductor is Ri Do a second balanced-side connection terminal,
The core conductor, the first and second ground conductors, and the first and second folded conductors have a length that is substantially an odd multiple of 1/4 of the wavelength of the radio signal to be transmitted. Balun device characterized by. A balun device according to claim 1 ;
A dipole antenna comprising two first antenna elements formed on a straight line and spaced apart from each other by a predetermined distance and connected to the first and second balanced connection terminals of the balun device An antenna device comprising: The core wire conductor, the first and second connection conductors, and the first and second folded conductors of the balun device are inclined or perpendicular to the two first antenna elements. The antenna device according to claim 2 , wherein the antenna device is formed. The substrate has first and second surfaces substantially parallel to each other;
The two first antenna elements are respectively
A first element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the first element conductor and through both ends of the first element conductor in the thickness direction. the antenna device according to claim 2 or 3, wherein further comprising a second element conductors having connected ends via hole conductor. The antenna according to claim 1, further comprising a reflective antenna element having a length longer than that of the dipole antenna, the second antenna element being formed parallel to the dipole antenna and spaced apart by a predetermined distance. The antenna device according to any one of 2 to 4 . The substrate has first and second surfaces substantially parallel to each other;
The second antenna element is
A third element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the third element conductor and through both ends of the third element conductor in the thickness direction. 6. The antenna device according to claim 5, further comprising a fourth element conductor having both ends connected via a hole conductor. A waveguide antenna element comprising a third antenna element that is parallel to the dipole antenna and spaced apart from the dipole antenna by a predetermined distance, and further has a shorter length than the dipole antenna. Item 7. The antenna device according to any one of Items 2 to 6 . The substrate has first and second surfaces substantially parallel to each other;
The third antenna element is
A fifth element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the fifth element conductor, and formed at both ends of the fifth element conductor and penetrating the substrate in the thickness direction. 8. The antenna device according to claim 7, further comprising a sixth element conductor having both ends connected via a hole conductor. Another balun device according to claim 1 ;
It consists of two fourth antenna elements formed on a straight line and spaced apart from each other by a predetermined distance, and connected to the first and second balanced connection terminals of the other balun device. the antenna device according to any one of claims 2 to 8, characterized in that a separate dipole antenna. The core wire conductor, the first and second connection conductors, and the first and second folded conductors of the other balun device are inclined or perpendicular to the two fourth antenna elements. The antenna device according to claim 9 , wherein the antenna device is formed as described above. The substrate has first and second surfaces substantially parallel to each other;
Each of the two fourth antenna elements is
A seventh element conductor formed on the first surface of the substrate;
A through hole formed on the second surface of the substrate so as to face the seventh element conductor, and formed so as to penetrate both ends of the seventh element conductor in the thickness direction. the antenna device according to claim 9 or 10, wherein further comprising an eighth element conductors having both ends connected through a hole conductor. A first unbalanced line connected to the unbalanced core terminal and unbalanced ground terminal of the balun device, and a second connected to the unbalanced core terminal and unbalanced ground terminal of the other balun device. the antenna device according to any one of claims 9 to 11, wherein the switching means for connecting further be provided with a selectively switched radio and unbalanced line of.

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