JP5425019B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device for performing polarization diversity by integrating antennas having different radiation patterns.

  It is effective to provide a wireless communication apparatus with a diversity function in order to cope with deterioration in multipath fading communication quality, increase communication speed, and increase capacity. Diversity schemes include space diversity, polarization diversity, pattern diversity, and the like, but it is common to increase the antenna interval in order to ensure isolation between a plurality of antennas. However, downsizing of wireless communication devices in recent years is strongly desired. Therefore, a sufficient distance between the antennas cannot be ensured, and the isolation effect is deteriorated and the diversity effect cannot be obtained.

  As a conventional technique for solving this problem, a composite antenna described in Patent Document 1 is known. According to the composite antenna described in Patent Document 1 below, an unbalanced antenna that is orthogonal to the ground is configured, and the balanced antenna is configured at a position symmetrical to the unbalanced antenna, and the antenna is integrated. And the unbalanced antenna are disclosed by mutually suppressing potential changes at the feeding points to ensure isolation.

International Publication No. 2007/055232 Pamphlet

  In Patent Document 1, a specific structure of a power feeding unit that supplies power to a balanced antenna is not disclosed, and there has been a problem in a method for realizing the structure. In addition, when the balanced antenna structure is symmetric with respect to the unbalanced antenna, the isolation between the antennas is ensured, so if the current distribution flowing over the antenna becomes asymmetric due to the influence of disturbance, etc. There has been a problem that potential changes occur at the feeding points of the balanced antenna and the unbalanced antenna, and the isolation between the antennas deteriorates.

  The present invention has been made to solve such a problem, and an object of the present invention is to obtain a small antenna device capable of realizing polarization diversity by integrating two antennas having different polarizations by a simple method. And It is another object of the present invention to provide an antenna device that can ensure isolation between antennas even when the antenna is housed in a housing of a wireless communication device.

  The present invention includes a ground conductor having a main surface, a first region in which an outer conductor is connected to the main surface of the ground conductor from one end to the other end, the main surface being spaced from the main surface of the ground conductor. A coaxial line that in turn includes a second region extending substantially parallel to the main surface of the ground conductor, and a third region extending in an upward direction of the main surface of the ground conductor, and a wavelength λ with respect to an operating frequency, and the second region of the coaxial line A transmission line having one end connected to the outer conductor at a position of approximately λ / 4 from the first region side end and the ground conductor as a ground, and substantially parallel to the third region from the other end side of the coaxial line A connection conductor having a length of approximately λ / 4, one end connected to the inner conductor at the other end of the coaxial line and the other end connected to the outer conductor in the third region, One end is connected to the connection conductor in the vicinity of the connection position between the conductor and the connection conductor, and the connection conductor One end is connected to the outer conductor at the other end of the coaxial line in the vicinity of the connection position between the first conductor extending at a degree, and the inner conductor of the coaxial line and the connecting conductor, forming an angle with the coaxial line. And a second conductor extending on the opposite side of the first conductor, a first feeding point for applying an AC voltage to the coaxial line, and a second feeding point for applying an AC voltage to the transmission line. An antenna device or the like is provided.

  According to the present invention, it is possible to provide a small antenna device or the like that can integrate polarization antennas by integrating two antennas having different polarizations by a simple method.

It is a perspective view which shows the structure of the antenna device which concerns on Embodiment 1 of this invention. It is the figure which showed typically the operation | movement of the antenna apparatus of FIG. It is the figure which showed typically the operation | movement of the antenna apparatus of FIG. It is a figure which shows the radiation pattern measured by making the prototype of the antenna apparatus of FIG. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 3 of this invention. It is the figure which showed typically the operation | movement of the antenna apparatus of FIG. It is the figure which showed typically the operation | movement of the antenna apparatus of FIG. It is a perspective view which shows the structure of the modification of the antenna device which concerns on Embodiment 3 of this invention. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 4 of this invention. It is a perspective view which shows the structure of the modification of the antenna device which concerns on Embodiment 4 of this invention. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 5 of this invention. It is a perspective view which shows the structure of the modification of the antenna device which concerns on Embodiment 5 of this invention. It is a perspective view which shows the structure of the antenna device which concerns on Embodiment 6 of this invention. It is a figure which shows the modification of the switching means of FIG.

  Hereinafter, an antenna device according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 1 of the present invention. In FIG. 1, the antenna device includes a ground conductor 1, a coaxial line 2, a transmission line 3, a connection conductor 4, a first conductor 5, and a second conductor 6.

  The ground conductor 1 is a conductor having a finite size, and has, for example, a rectangular shape having a main surface forming a transmission line as shown in FIG. The coaxial line 2 is electrically connected to the ground conductor 1 at the point A, and has a portion disposed substantially parallel or parallel to the ground conductor 1. The transmission line 3 is a transmission line that operates with the ground conductor 1 as the ground, and a planar circuit such as a microstrip line or a coplanar line is used. A coaxial line may be used. In that case, the outer conductor of the coaxial line is preferably electrically connected to the ground conductor 1. One end of the transmission line 3 (inner conductor in the case of a coaxial line) is electrically connected to the outer conductor of the coaxial line 2 at point B.

  That is, the coaxial line 2 is bent from the first region, point A, from the first feeding point 7 described later at one end to the point A where a part of the outer conductor is connected to the main surface of the ground conductor 1. A second region extending from a point BC to a point BC extending substantially parallel to or parallel to the main surface with a distance from the main surface 1, from the point BC to above the main surface of the ground conductor 1 (for example, substantially perpendicular or perpendicular to the main surface). The third region up to point C, which becomes the other end of the extending coaxial line 2, is included in order.

  One end of the connection conductor 4 is electrically connected to the inner conductor at the other end of the coaxial line 2 at the point C, and the other end is substantially the same as the coaxial line 2 electrically connected to the outer conductor of the coaxial line 2 at the connection point D. Parallel or parallel conductor. The first conductor 5 is a conductor whose one end is electrically connected to one end of the connection conductor 4 in the vicinity of the point C and extends at an angle with the connection conductor 4. The second conductor 6 has one end electrically connected to the outer conductor at the other end of the coaxial line 2 in the vicinity of the point C, forms an angle with the coaxial line 2, and extends to the opposite side of the first conductor 5. It is a conductor. A first feeding point 7 indicated by an AC power source is connected to one end of the coaxial line 2, and a second feeding point 8 indicated by an AC power source is connected to the other end of the transmission line 3.

  Next, the operation will be described. When an AC power source is connected to the first feeding point 7 to supply power, the AC signal output from the AC power source is (+) (plus) charge on the inner conductor of the coaxial line 2 and the outer conductor of the coaxial line 2. A (−) (minus) charge is distributed and transmitted through the coaxial line 2 to reach the point C. In the vicinity of the point C, the inner conductor and the first conductor 5 of the coaxial line 2 are connected, and the second conductor 6 is connected to the outer conductor of the coaxial line 2, so that the first conductor 5 and the second conductor 5 are connected. The conductor 6 constitutes a dipole antenna.

  Here, since the dipole antenna is a balanced antenna, the coaxial line 2 is an unbalanced feed line. Therefore, when both are connected as they are, an unbalanced current is generated outside the outer conductor of the coaxial line 2. Will adversely affect antenna performance.

In the antenna device according to the first embodiment of the present invention, the connection conductor 4 is connected to the inner conductor of the coaxial line 2 at the point C and is connected to the outer conductor of the coaxial line 2 at the point D. A short-circuited transmission line is formed by the outer conductor of the line 2. At this time, the impedance Z _CD viewed from the point C to the point D is

Z _CD = jZ _0a tan {(2π / λ) L _a } (1)

It is expressed. Z _0a : Characteristic impedance of the transmission line constituted by the connecting conductor 4 and the outer conductor of the coaxial line 2
L _a : Distance between point C and point D
λ: wavelength with respect to the operating frequency. As is apparent from equation (1), L _a is the impedance Z _CD viewed point D from point C when satisfying the following equation (2) is infinite.

L _a = {(2n + 1) / 4} λ (n is an integer of 0 or more) (2)

Therefore, if you choose the distance L _a of the point C and the point D so as to satisfy the equation (2), unbalance current can be prevented from flowing through the outer conductor of the coaxial line 2. If the antenna device is downsized, L _a = λ / 4 or L _a ≈λ / 4.

On the other hand, when an AC power source is connected to the second feeding point 8 to supply power, the AC signal output from the AC power source reaches the outer conductor of the coaxial line 2. Here, the outer conductor of the coaxial line 2 is connected to the ground conductor 1 at the point A, and a short-circuited transmission line is formed by the portion where the coaxial line 2 and the ground conductor 1 are arranged substantially in parallel. At this time, the impedance Z _BA seen from point B to point A is

Z _BA = jZ _0b tan {(2π / λ) L _b } (3)

It is expressed. Where Z _{0b is} the characteristic impedance of the transmission line constituted by the outer conductor of the coaxial line 2 and the ground conductor 1,
L _b : the distance between point B and point A. As apparent from the equation (3), when the L _b satisfies the following equation (4), the impedance Z _BA seen from the point B to the point A becomes infinite.

L _b = {(2m + 1) / 4} λ (m is an integer of 0 or more) (4)

Therefore, if the distance between the points B and A is selected so as to satisfy the expression (4) (L _b = λ / 4 or L _a ≈λ / 4 if the antenna device is downsized), the transmission line The AC signal (current) transmitted from 3 does not flow toward the point A, and power is supplied to the connection conductor 4 and a portion substantially parallel to the connection conductor 4 of the outer conductor of the coaxial line 2. (Between C and point D) operates as a monopole antenna.

  2 and 3 schematically show the operation described above. 2 shows a case where an AC power source is connected to the first feeding point 7 and power is supplied, and FIG. 3 shows a case where an AC power source is connected to the second feeding point 8 and power is supplied. In FIG. 2, 9 is a current flowing on the first conductor 5 and the second conductor 6. In FIG. 3, 10 is a current flowing on the first conductor 5 and the second conductor 6, and 11 is a current flowing in a portion substantially parallel to the connecting conductor 4 and the connecting conductor 4 of the outer conductor of the coaxial line 2. 2 and 3, the directions of the currents 9, 10, and 11 depend on the period according to the frequency of the AC signal output from the AC power source connected to the first feeding point 7 and the second feeding point 8. Switch alternately.

  When an AC power source is connected to the first feeding point 7 to feed power, the current that contributes to radiation is the current 9 that flows on the first conductor 5 and the second conductor 6. On the other hand, when an AC power supply is connected to the second feeding point 8 and the power is fed, the current contributing to radiation is the current 11 flowing through the connection conductor 4 and the connection conductor 4 of the outer conductor of the coaxial line 2. . Since the currents 10 flowing on the first conductor 5 and the second conductor 6 flow in opposite directions, they do not contribute to radiation.

  FIG. 4 shows a prototype of the antenna device according to Embodiment 1 of the present invention, and shows radiation patterns on the zx plane and the zy plane of the xyz coordinates in which the xz plane shown in FIG. It is a figure which shows the measurement result. 4A shows a radiation pattern when an AC power source is connected to the first feeding point 7 and power is supplied. FIG. 4B shows a radiation pattern when the AC power source is connected to the second feeding point 8 and power is supplied. Represents.

When power is supplied by connecting an AC power source to the first feeding point 7, the current that contributes to radiation is the current 9, and thus the E _θ component is an 8-shaped pattern of the main polarization in the _zx plane. Become. In the zy plane, the _Eφ component is a substantially omnidirectional pattern of the main polarization. On the other hand, when an AC power supply is connected to the second feeding point 8 and the power is fed, the current that contributes to radiation is the current 11, so that the _Eφ component is a substantially omnidirectional pattern of the main polarization in the _zx plane. It becomes. In the yz plane, the _Eθ component becomes an 8-shaped pattern of the main polarization.

  In this way, the polarization of the radiated radio wave is switched between when the AC power is connected to the first feeding point 7 and feeding is performed and when the AC power is connected and fed to the second feeding point 8. Thus, a small polarization diversity antenna can be obtained.

Embodiment 2. FIG.
FIG. 5 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 2 of the present invention. The difference from the first embodiment is that a balanced line 12 is used instead of the coaxial line 2 and the connection conductor 4. In addition, illustration of the AC power supply of the first and second feeding points 7 and 8 is omitted (the same applies hereinafter).

  The balanced line 12 shown in FIG. 5 is composed of two inner conductors and an outer conductor covering the periphery thereof. On the other end side of the balanced line 12, one of the inner conductors is electrically connected to the first conductor 5, and the other inner conductor is electrically connected to the second conductor 6. A part of the balanced line 12 is disposed substantially parallel or parallel to the ground conductor 1 at a predetermined distance, and the outer conductor of the balanced line 12 is electrically connected to the ground conductor 1 at the connection point A. Furthermore, the outer conductors of the transmission line 3 and the balanced line 12 are electrically connected at the connection point B.

  In other words, the balanced line 12 is bent from the first region, the first region from the first feeding point 7 at one end to the point A where a part of the outer conductor is connected to the main surface of the ground conductor 1, and the ground conductor 1 A second region extending from the BC point to a point BC extending substantially parallel to or parallel to the main surface with a space from the main surface, and an equilibrium extending from the BC point above the main surface of the ground conductor 1 (for example, substantially perpendicular or perpendicular to the main surface). The third region up to point C that becomes the other end of the line 12 is included in order.

  First and second power feeds connected to an AC power source (not shown) on one end side opposite to the other end side to which the first conductor 5 and the second conductor 6 of the balanced line 12 are connected. Points 7 and 8 are provided and an AC signal is applied. As a result, the first conductor 5 and the second conductor 6 form a dipole antenna. Here, since the dipole antenna is a balanced antenna, an unbalanced current does not flow through the outer conductor of the feed line when the dipole antenna is fed with a balanced line. Therefore, an unbalanced current does not flow through the outer conductor of the balanced line 12 in the antenna device of the second embodiment.

  Even in such a configuration, a short-circuited transmission line is formed by the portion where the balanced line 12 and the ground conductor 1 are arranged substantially in parallel, and power is supplied to the outer conductor of the balanced line 12 through the transmission line 3. Accordingly, a monopole antenna is formed between the point C and the point B of the balanced line 12 in the same manner as the operation described in the first embodiment. That is, it is possible to switch the polarization of the radio wave radiated between when the balanced line 12 is fed and when the transmission line 3 is fed, and a small polarization diversity antenna can be obtained.

  In the antenna device of the second embodiment, the balanced line 12 is used to supply power to the dipole antenna composed of the first conductor 5 and the second conductor 6, thereby omitting the structure for preventing the unbalanced current. Can be manufactured easily.

Embodiment 3 FIG.
FIG. 6 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 3 of the present invention. In FIG. 6, the antenna device includes a ground conductor 1 (for example, a plate shape), a T-shaped conductor 13, a first slit 14, a second slit 15, a first feeding point 7, 2 feeding points 8.

  The difference from the first embodiment and the second embodiment is that a substantially T-shaped or T-shaped conductor 13 is arranged in place of the connecting conductor 4 and the first and second conductors 5 and 6, and the T-shaped The first slit 14 is provided in the conductor 13 and the second slit 15 is provided in the ground conductor 1.

  The T-shaped conductor 13 has one end electrically connected to the ground conductor 1 (main surface or side surface) and the other end extending upward (for example, substantially perpendicular or perpendicular to the main surface) of the main surface of the ground conductor 1. A line conductor 13 a, a first slit 14 that extends from the other end of the line conductor 13 a toward one end, and divides the line conductor 13 a into two, and a line conductor 13 a on one side divided by the first slit 14. A first conductor 13b extending at an angle with the line conductor from the other end and an angle with the line conductor from the other end of the other line conductor 13a divided by the first slit 14 and the first conductor 13b. A second conductor 13c extending on the opposite side of the conductor 13b.

  Further, the ground conductor 1 is provided with a second slit 15 extending inward from an end in the vicinity of a portion where the lower end (one end side) of the T-shaped conductor 13 is electrically connected. The second slit 15 has, for example, an L-shape that extends inward for a first predetermined length, bends substantially at a right angle, and extends in parallel with the edge of the ground conductor 1 for a second predetermined length.

  The first feeding point 7 is provided near the open end of the first slit 14, and the second feeding point 8 is provided near the open end of the second slit 15.

Next, the operation will be described. When an AC power supply is connected to the first power supply point 7 to supply power, a (+) (plus) charge is applied to one of the line conductors 13a separated by the first slit 14 by an AC signal output from the AC power supply. A (−) (minus) charge is induced on the opposite side. At this time, when viewed from the first feeding point 7, the first slit 14 operates as a short-circuited transmission line. At this time, the impedance Z ₇ when the end (short-circuit end) of the slit is viewed from the first feeding point ₇ is

Z ₇ = jZ _0c tan {(2π / λ) L _c } (5)

It is expressed. Where Z _{0c is} the characteristic impedance of the transmission line by the first slit 14
L _c is the distance from the first feeding point 7 to the end (short-circuit end) of the first slit 14. As apparent from the equation (5), when L _c satisfies the following equation (6), the impedance Z ₇ seen from the first feeding point 7 to the end (short-circuited end) of the first slit 14 is infinite. Become.

L _c = {(2k + 1) / 4} λ (k is an integer greater than or equal to 0) (6)

Therefore, if you choose L _c so as to satisfy the equation (6), it is possible to prevent the flow of current in the line conductor 13a, first and second conductors 13b, the current to 13c flows.

On the other hand, when an AC power supply is connected to the second power supply point 8 to supply power, (+) (plus) is added to one of the ground conductors 1 separated by the second slit 15 by the AC signal output from the AC power supply. Charge is induced and (-) (minus) charge is induced on the opposite side. Accordingly, the second slit 15 also operates as a short-circuited transmission line when viewed from the second feeding point 8. At this time, the impedance Z ₈ when the end (short-circuit end) of the slit is viewed from the second feeding point ₈ is

Z ₈ = jZ _0d tan {(2π / λ) L _d } (7)

It is expressed. Here, Z _0d : Characteristic impedance of the transmission line by the second slit 15
L _d is the distance from the second feeding point 8 to the end (short-circuit end) of the second slit 15. As apparent from the equation (7), when L _d satisfies the following equation (8), the impedance Z _{8 when} the end (short-circuited end) of the second slit 15 is viewed from the second feeding point ₈ is infinite. Become.

L _d = {(2l + 1) / 4} λ (l is an integer of 0 or more) (8)

Since the second slit 15 is adjacent to the portion of the line conductor 13a and the ground conductor 1 is connected, if you choose L _d so as to satisfy the equation (8), induced by the second feed point 8 The current flows through the line conductor 13a without flowing through the ground conductor 1.

  7 and 8 schematically show the operation described above. FIG. 7 shows a case where an AC power source is connected to the first feeding point 7 and power is supplied. FIG. 8 shows a case where an AC power source is connected to the second feeding point 8 and the power is supplied. In FIG. 7, reference numeral 18 denotes a current flowing through the first and second conductors 13b and 13c. In FIG. 8, 19 is a current flowing through the first and second conductors 13b and 13c, and 20 is a current flowing through the line conductor 13a. 7 and 8, the directions of the currents 18, 19, and 20 depend on the period according to the frequency of the AC signal output from the AC power source connected to the first feeding point 7 and the second feeding point 8. Switch alternately.

When an AC power supply is connected to the first feeding point 7 to feed power, the current contributing to radiation is the current 18 shown in FIG. Therefore, in the zx plane, the _Eθ component becomes an 8-shaped pattern of the main polarization. In the zy plane, the _Eφ component is a substantially omnidirectional pattern of the main polarization. On the other hand, when power is supplied by connecting an AC power source to the second feeding point 8, the current flowing on the T-shaped conductor 13 reaches the first and second conductors 13b and 13c through the line conductor 13a. . Therefore, the currents flowing through the first and second conductors 13b and 13c are opposite to each other on the left and right of the first slit 14 as shown in FIG. For this reason, the current 19 does not contribute to the radiation, and the current 20 flowing through the line conductor 13a contributes to the radiation. Therefore, the _Eφ component becomes a substantially omnidirectional pattern of the main polarization on the z-x plane, and the _Eθ component becomes an 8-shaped pattern of the main polarization on the _zy plane.

  As described above, also in the antenna device of the third embodiment, as in the first embodiment, the deviation of radio waves radiated when the power is fed to the first feeding point 7 and when the second feeding point 8 is fed. Waves can be switched, and a small polarization diversity antenna can be obtained.

  Here, by using the dielectric substrate, the ground conductor 1, the second slit 15, the T-shaped conductor 13, and the first slit 14 can be formed on the dielectric substrate by etching. By doing in this way, the feed line for feeding in the 1st feed point 7 can be comprised by the transmission line which makes the ground conductor 1 and the T-shaped conductor 13 the ground. In addition, mass production can be easily performed by etching, leading to cost reduction.

  In the third embodiment, an unbalanced-balanced conversion line such as a taper balun can be used by the first slit 14. FIG. 9 shows an example of a configuration in which a taper balun and a dipole antenna are combined. In FIG. 9, the antenna device includes a ground conductor 1, a slit 15, a transmission line 41, a first feeding point 7, a second feeding point 8, and a substrate 21. The board | substrate 21 is a plate-shaped board | substrate which has a finite size, for example, as shown in FIG. 9, it is a substantially T shape or T shape.

  The substrate 21 has one end electrically connected to the ground conductor 1 (main surface or side surface) and one end above the main surface of the ground conductor 1 (for example, substantially perpendicular to the main surface or A tapered conductor 23b that extends toward the vertical direction and narrows from one end to the other end, and a first conductor 23a that extends from the other end of the tapered conductor 23b at an angle to the tapered conductor 23b. The other end is arranged substantially parallel to the tapered conductor 23b and extends from one end to the other end above the main surface of the ground conductor 1 (for example, substantially perpendicular or perpendicular to the main surface). And a second conductor 22a extending from the other end of the linear conductor 22b at an angle to the linear conductor and extending to the opposite side of the first conductor 23a.

The ground conductor 1 has a ground conductor 1 in the vicinity of the connection position of the transmission line 41 having the ground conductor 1 as the ground and one end electrically connected to one end of the linear conductor 22b, and the ground conductor 1 and the tapered conductor 23b. From the slit 15 provided so as to extend inward from one end, the first feeding point 7 that applies an AC voltage to the transmission line 41, and the short-circuited end of the slit 15 when the wavelength with respect to the operating frequency is λ A second feeding point 8 is provided near the open end of the slit 15 at a position of approximately λ / 4 and applies an AC voltage to the slit 15.
The transmission line 41 corresponds to the coaxial line 2 of the first embodiment and the parallel line 12 of the second embodiment. The microstrip line, the coplanar line, and the coaxial line (in the case of a coaxial line, the inner conductor thereof becomes the linear conductor 22b. Connection).

When operating the dipole antenna composed of the first conductor 23a and the second conductor 22a, power is supplied from the first feeding point 7 as in the first and second embodiments, for example, and the tapered conductor 23b is operated as a monopole antenna. When this is done, power is fed from the second feeding point 8 as in the third embodiment.
In the substrate 21, by gradually changing the width of the tapered conductor 23b, this portion operates as a tapered balun. Accordingly, balanced power can be supplied to the dipole antenna composed of the first conductor 23a and the second conductor 22a, and unbalanced current can be suppressed.

Embodiment 4 FIG.
FIG. 10 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 4 of the present invention. In FIG. 10, the difference from the third embodiment is that the first conductor 13 b and the second conductor 13 c of the T-shaped conductor 13 are asymmetric with respect to the first feeding point 7. .

  In general, in the case of an antenna built in the housing of a wireless communication device, there are many other structures such as other modules and circuit boards arranged in the vicinity of the antenna. ) Changes the antenna characteristics. For this reason, it is necessary to design the antenna built into the housing including surrounding structures and determine the shape of the antenna in consideration of the influence of the surroundings. At this time, the antenna characteristics may be improved by making the shape of the antenna asymmetric.

  Note that the first conductor 13 b and the second conductor 13 c shown in FIG. 10 are also physically asymmetric with respect to the first slit 14. However, for example, as shown in FIG. 11, the same effect can be obtained by making the electrical length asymmetrical by cutting a part of the first conductor side and inserting a lumped constant element 24 between the conductor 13ba and the conductor 13bb. Can be obtained. As the lumped constant element 24, an element having an arbitrary reactance (inductance or capacitance) is used.

  As described above, according to the antenna device according to Embodiment 4, it is possible to obtain an antenna device that can obtain good characteristics even when incorporated in a housing of a wireless communication device.

Embodiment 5 FIG.
FIG. 12 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 5 of the present invention. 12 is different from the third embodiment in that the first slit 14 of the T-shaped conductor 13 is provided at an asymmetrical position of the T-shaped conductor 13.

  As described above, in the antenna built in the housing of the wireless communication apparatus, even if the antenna structure is symmetric, the current distribution on the antenna may be asymmetric due to the influence of the surrounding structure. At this time, electrical isolation between the first feeding point 7 and the second feeding point 8 is deteriorated.

  Therefore, in the antenna device according to Embodiment 5 of the present invention, by providing the first slit 14 at the asymmetric position of the T-shaped conductor 13, this asymmetry can be canceled and the isolation can be improved. As another means for canceling the asymmetry, it is also effective to incline the line conductor 13a of the T-shaped conductor 13 with respect to the ground conductor 1 as shown in FIG. The tilt direction and angle are selected according to the characteristics to be obtained.

  As described above, according to the antenna device of the fifth embodiment, it is possible to obtain a polarization diversity antenna that can ensure good isolation even if it is built in the casing of the wireless communication device.

Embodiment 6 FIG.
FIG. 14 is a perspective view showing a configuration of an antenna apparatus according to Embodiment 5 of the present invention. 14 is different from the first embodiment in that the first switch 25 is inserted between the first feeding point 7 and the coaxial line 2 and the second feeding point 8 and the transmission line 3 are second. The switch 26 is inserted. A first feeding point 7 and a first reactance element 27 are connected to the first switch 25, and a second feeding point 8 and a second reactance element 28 are connected to the second switch 26.

  The correlation coefficient indicating the degree of coincidence of the radiation patterns between the two antennas varies depending on the termination condition of the antenna that is not used. That is, if an appropriate reactance value is selected, the radiation pattern correlation coefficient between the two antennas can be reduced.

  In the antenna device according to the sixth embodiment, the unused feeding point can be terminated with a reactance element having an arbitrary reactance value, so that a polarization diversity antenna with a small correlation coefficient can be obtained. Therefore, an antenna device with a high diversity effect can be obtained.

  In FIG. 14, the first switch 25 and the second switch 26 are connected to the coaxial line 2 and the transmission line 3, respectively. However, the present invention is not limited to such a configuration. An arbitrary configuration can be applied as long as switching that can be terminated by a reactance element is possible. For example, as shown in FIG. 15, the termination can be switched by using one switch 29. In FIG. 15, when the common feeding point 30 is connected to the terminal of the point F connected to the transmission line 3 as shown in the drawing, the first reactance element 27 is connected to the terminal of the point E, and the feeding point For example, when 30 is connected to the terminal of point E connected to the coaxial line 2, the second reactance element 28 is connected to the terminal of point F.

  The first conductors 5, 13b, 13ba, 13bb, and 23a and the second conductors 6, 13c, and 22a according to each embodiment are linear, meandered, and have a predetermined width. Any shape can be selected as long as resonance is obtained at a desired frequency, such as a circular shape, a cylindrical shape, a circular shape, or a partial shape of a circle (fan shape).

The configuration of the sixth embodiment has been described based on the configuration of the first embodiment. However, the configuration is not limited to this configuration, and can be similarly applied to the configurations described in the second to fifth embodiments. A considerable effect can be obtained.
Further, the present invention is not limited to the individual embodiments described above, and it goes without saying that all possible combinations of these embodiments are included.

  1 ground conductor, 2 coaxial line, 3 transmission line, 4 connection conductor, 5, 13b, 13ba, 13bb, 23a first conductor, 6, 13c, 22a second conductor, 7 first feeding point, 8 second Feeding point, 12 parallel lines, 13 T-shaped conductor, 13a line conductor, 14 first slit, 15 second slit, 21 T-shaped substrate, 22b linear conductor, 23b tapered conductor, 24 concentration Constant element, 25 1st switch, 26 2nd switch, 27 1st reactance element, 28 2nd reactance element, 29 switch, 30 Feeding point, 41 Transmission line.

Claims (13)

A ground conductor having a main surface;
A first region in which an outer conductor is connected to a main surface of the ground conductor from one end to the other end, a second region extending substantially parallel to the main surface at a distance from the main surface of the ground conductor, and the ground conductor A coaxial line that in turn includes a third region extending upward from the main surface of
Transmission with the ground conductor as the ground, with one end connected to the outer conductor at a position substantially λ / 4 from the end of the second region of the coaxial line at the wavelength λ with respect to the operating frequency. Tracks,
Λ extending substantially parallel from the other end side of the coaxial line along the third region, having one end connected to the inner conductor at the other end of the coaxial line and the other end connected to the outer conductor in the third region. A connecting conductor having a length of / 4;
A first conductor having one end connected to the connection conductor and extending at an angle with the connection conductor in the vicinity of a connection position between the inner conductor of the coaxial line and the connection conductor;
In the vicinity of the connection position between the inner conductor of the coaxial line and the connection conductor, one end is connected to the outer conductor at the other end of the coaxial line and forms an angle with the coaxial line and extends to the opposite side of the first conductor. Two conductors,
A first feeding point for applying an AC voltage to the coaxial line;
A second feeding point for applying an AC voltage to the transmission line;
An antenna device comprising: A ground conductor having a main surface;
A balanced line covering the periphery of two inner conductors with an outer conductor, the first region having a part of the outer conductor connected to the main surface of the ground conductor from one end to the other end, A second region extending substantially parallel to the main surface at a distance from the main surface, and a third region extending in an upward direction above the main surface of the ground conductor,
Transmission with the ground conductor as the ground, one end of which is connected to the outer conductor at a position substantially λ / 4 from the end of the second region of the balanced line on the first region side when the wavelength λ is the operating frequency. Tracks,
A first conductor having one end connected to one of the two inner conductors at the other end of the balanced line and extending at an angle with the balanced line;
A second conductor having one end connected to the other of the two inner conductors at one end of the balanced line and forming an angle with the balanced line and extending to the opposite side of the first conductor;
A first feeding point for applying an AC voltage to the balanced line;
A second feeding point for applying an AC voltage to the transmission line;
An antenna device comprising: A ground conductor having a main surface;
A line conductor having one end connected to the ground conductor and the other end extending above the main surface of the ground conductor;
A first slit extending from the other end of the line conductor toward one end;
A first conductor extending at an angle with the line conductor from the other end of the line conductor on one side of the first slit;
A second conductor that forms an angle with the line conductor from the other end of the line conductor on the other side of the first slit and extends to the opposite side of the first conductor;
In the vicinity of the connection position of the ground conductor and the line conductor, a second slit provided to extend inward from the end of the ground conductor;
A first feeding point for applying an alternating voltage provided near the open end of the first slit at a position of approximately λ / 4 from the short-circuited end of the first slit, where the wavelength with respect to the operating frequency is λ. ,
A second feeding point for applying an AC voltage provided near the open end of the second slit at a position of approximately λ / 4 from the short-circuited end of the second slit;
An antenna device comprising:   The antenna device according to claim 3, wherein the first slit is provided so as to be shifted from an axis of symmetry extending from one end to the other end of the line conductor. A ground conductor having a main surface;
A tapered conductor having one end connected to the ground conductor and the other end extending above the main surface of the ground conductor, the width of which decreases from one end to the other end;
A linear conductor disposed substantially parallel to the tapered conductor, extending from one end to the other end upward of the main surface of the ground conductor, and having a constant width from one end to the other end;
A first conductor extending at an angle with the tapered conductor from the other end of the tapered conductor;
A second conductor that forms an angle with the linear conductor from the other end of the linear conductor and extends to the opposite side of the first conductor;
The ground conductor as a ground, a transmission line having one end connected to one end of the linear conductor,
In the vicinity of the connection position of the ground conductor and the tapered conductor, a slit provided to extend inward from the end of the ground conductor;
A first feeding point for applying an AC voltage to the transmission line;
A second feeding point that is provided in the vicinity of the open end of the slit at a position of approximately λ / 4 when the wavelength with respect to the operating frequency is λ from the short-circuited end of the slit and applies an AC voltage to the slit;
An antenna device comprising:   The antenna device according to claim 1, wherein the connection conductor and the third region of the coaxial line are arranged to be inclined with respect to the main surface of the ground conductor.   The antenna device according to claim 2, wherein the third region of the balanced line is disposed to be inclined with respect to the main surface of the ground conductor.   The antenna device according to claim 3 or 4, wherein the line conductor is disposed to be inclined with respect to a main surface of the ground conductor.   6. The antenna device according to claim 5, wherein the linear conductor and the tapered conductor are arranged to be inclined with respect to a main surface of the ground conductor.   The antenna device according to any one of claims 1 to 9, wherein the first conductor and the second conductor are different in physical size or electrical characteristics.   A switching means for selectively connecting a power source when a voltage is applied to each of the first feeding point and the second feeding point and a reactance element having a predetermined value when no voltage is applied is provided. The antenna device according to claim 1, wherein the antenna device is characterized in that:   The first conductor and the second conductor are any one of a linear shape, a meander-shaped structure, a plate shape having a predetermined width, a cylindrical shape, a circular shape, and a partial shape of a circle. The antenna device according to any one of claims 1 to 11, wherein the antenna device is characterized in that:   The antenna device according to any one of claims 3, 4, 5, 8, and 9, wherein the entire antenna device is formed of a dielectric substrate.

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