JP2000278039A - Antenna shared for polarized waves - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna shared for a polarized waves that can make transmission reception at different frequencies by independently operating polarized wave diversity antennas with different resonance frequencies each having a narrow frequency band that are placed on a same plane at each of the different frequency bands. SOLUTION: In this antenna, a 1st antenna 1 that can independently excite a polarized wave plane A and a polarized wave plane B orthogonal to the polarized wave plane A, a 2nd antenna 3 that can independently excite the polarized wave plane A and the polarized wave plane B are placed adjacent to each other. Feeders 2, 4 to feed power to the respective antennas 1, 3 are connected to a common coupling point 6 and 1st feeders 2, 4 to excite the polarized wave plane A and a 2nd feeder 5 to excite the polarized wave plane B are provided independently to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual-polarization antenna suitable for a mobile communication base station antenna which is widely used for both transmission and reception. The present invention relates to a dual-polarized antenna capable of transmitting and receiving at different frequencies by independently operating antennas arranged and used in different frequency bands.

[0002]

2. Description of the Related Art FIG. 10 shows "Antenna" supervised by RC Johnson.
Engineering Handbook Third Edition ”McGraw-Hill, In
c., PP.7-17 and FIG. 7-24 are configuration diagrams of the stacked dual-frequency microstrip antenna shown in FIGS. 10, 601 is a low-frequency element antenna, 602 is a high-frequency band element antenna, 603 is a feed probe of the antenna,
604 is a main plate.

In this antenna, two types of microstrip antennas having different resonance frequencies and narrow bands are stacked (multilayered), and a feeding probe is physically connected to an upper antenna element through a small hole provided in an element conductor of the lower antenna. Is joined to. Each antenna is equivalent to a short circuit except at the resonance frequency.Because the low-frequency antenna and high-frequency antenna can be regarded as connected in series by a probe, each antenna operates independently at each resonance frequency. Thus, a two-frequency resonance characteristic is exhibited.

FIG. 11 shows Kyohei Fujimoto, "Illustrated Antenna System for Mobile Communication", Sogo Denshi Shuppan, pp. 139-143.
FIG. 128 is a configuration diagram of the polarization diversity base station antenna shown in FIG. 128 and FIG. 4.26. In FIG. 11, reference numeral 701 denotes a circular patch antenna serving as a radiating element, 702 denotes a horizontal polarization feeding point, 703 denotes a vertical polarization feeding point, 704 denotes a dielectric substrate,
705 is a radome, 706 is a parasitic element, 707 is a microstrip line as a power supply circuit, and 708 is a ground plane (conductor).

In this antenna, a circular patch antenna 701 is used as a radiating element,
01 is supplied by a microstrip line 707.
Further, the antenna is broadened by loading the parasitic element 706 to cover the transmission and reception frequency band.

[0006]

In a conventional polarization diversity antenna using a patch antenna, a parasitic element is loaded on a patch antenna which is originally narrow band, or the antenna is stacked to transmit and receive signals at different frequencies. In order to make it possible, the antenna must have a multilayer structure,
In addition, there is a problem that frequency adjustment is difficult.

In the stacked two-frequency antenna shown in FIG. 10, when the antenna is processed by etching and then the antenna is stacked, the work process becomes more complicated and the cost becomes higher than when a non-stacked antenna is manufactured. To increase.
It is also difficult to readjust the antenna after processing.

Further, in the conventional antenna device shown in FIG. 11, when transmission and reception are performed at a frequency having a frequency interval wider than the band of the patch antenna alone, it is necessary to load a parasitic element to widen the antenna bandwidth. Therefore, there is a problem in that the efficiency of antenna fabrication and assembly work due to antenna multilayering is low. Furthermore, since the characteristics of the patch antenna loaded with the parasitic element and having a wide band are easily affected by the radome, there is a problem that the adjustment operation is complicated. In addition, there is a problem that frequency characteristics of directivity are large.

When an array antenna is configured for mobile communication, the elements are generally arranged with the element spacing being one wavelength or less at the element upper limit frequency in the band upper limit frequency. However, if adjacent elements are too close together, mutual coupling between the elements will increase and the characteristics will deteriorate. As a result, it is necessary to make the element arrangement sparse to some extent, and the use efficiency of the antenna installation space deteriorates.

[0010] Therefore, an object of the present invention is to solve the above-mentioned problems, and arrange narrow-band polarization diversity antennas having different resonance frequencies on the same plane to independently operate antennas used in different frequency bands. Accordingly, it is an object of the present invention to provide a dual-polarized antenna capable of transmitting and receiving at different frequencies.

[0011]

In order to achieve the above object, the present invention provides a dual-polarization antenna for transmitting and receiving at different frequencies, in which a polarization plane A and a polarization plane B orthogonal to the polarization plane A are independent. And a second antenna capable of independently exciting the polarization plane A and the polarization plane B are disposed adjacent to each other, and a feed line for supplying power to each antenna is provided at a common coupling point. , And a first feed line for exciting the polarization plane A and a second feed line for exciting the polarization plane B are provided independently of each other.

When the impedance on the antenna side is viewed from the coupling point, the impedance of the second antenna is substantially open at the resonance frequency of the first antenna, and the first antenna is at the resonance frequency of the second antenna. May be substantially open.

[0013] Transmission and reception on the same polarization plane may be performed using different antennas.

[0014] The dimensions of the first antenna and the dimensions of the second antenna may be different.

The first antenna is strongly sensitive to the transmission frequency band power on the polarization plane A and hardly sensitive to the reception frequency band power, and the second antenna is sensitive to the reception frequency band power for each of the polarization plane A and the polarization plane B. It may be strongly sensitive and less sensitive to transmission frequency band power.

The first antenna is strongly sensitive to the transmission frequency band power and hardly sensitive to the reception frequency band power for each of the polarization plane A and the polarization plane B, and the second antenna is for each of the polarization plane A and the polarization plane B. May be strongly sensitive to the reception frequency band power and difficult to respond to the transmission frequency band power.

The first antenna is strongly sensitive to the transmission frequency band power on the polarization plane A and hardly sensitive to the reception frequency band power, and is strongly sensitive to the reception frequency band power and sensitive to the transmission frequency band power on the polarization plane B. The second antenna is hardly sensitive to the reception frequency band power with respect to the polarization plane B,
The polarization plane A may be strongly sensitive to the reception frequency band power and difficult to be sensitive to the transmission frequency band power.

The first antenna is strongly sensitive to the transmission frequency band power on the polarization plane A and hardly sensitive to the reception frequency band power, and is strongly sensitive to the reception frequency band power and sensitive to the transmission frequency band power on the polarization plane B. The second antenna is strongly sensitive to the transmission frequency band power on the polarization plane B and is hardly sensitive to the reception frequency band power, and the second antenna is strongly sensitive to the reception frequency band power and the transmission frequency band power on the polarization plane A. It may not be easy.

[0019]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a configuration diagram of a dual-polarization antenna according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged view of the dual-polarization antenna of FIG. Here, it is assumed that the dual-polarization antenna transmits vertically polarized waves and performs polarization diversity reception using vertically polarized waves and horizontally polarized waves.

1 and 2, reference numeral 1 denotes a rectangular patch antenna serving as a transmission frequency band antenna, reference numeral 2 denotes a microstrip line which is a feed line for vertical polarization of the transmission frequency band antenna 1, and reference numeral 3 denotes a reception frequency band antenna. , A microstrip line as a vertical polarization feed line of the reception frequency band antenna 3, a microstrip line as a horizontal polarization feed line of the reception frequency band antenna 3, and 6. A microstrip line, which is a feed line for both vertically polarized wave transmission and reception, 7 is a dielectric layer, and 8 is a ground plane. That is, this dual-polarized antenna has a dielectric layer 7 provided on a ground plane 8 and a patch or a microstrip line made of a conductor formed on the surface of the dielectric layer 7. The vertical polarization feed line 2 is a transmission frequency band antenna 1.
Is drawn out at a right angle from almost the center of the lower side, bent at a right angle and extended to the right. The vertical polarization feed line 4 is drawn out at a right angle from substantially the center of the upper side of the reception frequency band antenna 3, bent at a right angle, and extended rightward. The horizontal polarization feed line 5 is drawn out at a right angle from substantially the center of the left side of the reception frequency band antenna 3, bent at a right angle, and extended upward.

As shown in the figure, in the dual-polarization antenna of the present invention, antennas 1 and 3 that can excite vertical polarization and horizontal polarization independently are arranged adjacent to each other. The power supply lines 2 and 4 for supplying power have a common connection point 6
Feed lines 2, 4 for exciting vertical polarization
And a feed line 5 for exciting horizontal polarization are provided independently of each other. The array antenna of FIG. 1 is configured by vertically arranging the dual-polarized antenna of FIG. 2 including the first and second antennas at predetermined intervals.

The array antenna shown in FIG. 1 will be described in detail. Here, this array antenna is used for a base station for mobile communication. This array antenna is arranged so that the element interval is one wavelength or less at the upper limit of the used frequency band. If the element spacing is one wavelength or more, a grating globe is generated, and the gain of the array antenna is reduced. In order to obtain a large directivity gain and to prevent a decrease in antenna efficiency due to mutual coupling between elements, it is preferable to make the element spacing as large as possible within a range in which the element spacing is one wavelength or less at the upper limit of the used frequency band.

When an array antenna is formed by providing a dielectric layer between a patch and a ground plane as in the array antenna of FIG. 1, the apparent element spacing is further increased because the elements are reduced in size by the dielectric constant. . On the other hand, an antenna miniaturized by the dielectric constant has a narrow band. If the transmission band or the reception band can be covered by the miniaturized antenna, an antenna that transmits and receives at different frequencies without multilayering the antenna can be realized. For example, the transmitting array antennas arranged at the interval s and the receiving array antennas arranged at the interval s are arranged on the same substrate while being shifted by s / 2. As shown in FIG. 1, an array directivity shaping power supply circuit is formed by combining one element of the transmitting antenna (the antenna 1 for the transmitting frequency band) and one element of the receiving antenna (the antenna 3 for the receiving frequency band). Connect to The array directivity shaping power supply circuit is provided independently for each of vertical polarization and horizontal polarization.

It is needless to say that the structure of the transmitting antenna and the receiving antenna may be other than a rectangular patch antenna as long as it has sensitivity to two polarizations orthogonal to each other. Further, the two polarizations need not be a vertical polarization and a horizontal polarization. Further, when the transmitting array antenna and the receiving array antenna are one-dimensionally arranged on the same plane, if the elements of the transmitting antenna and the elements of the receiving antenna do not physically contact, s / 2 or less, Alternatively, they can be shifted by s / 2 or more.

In the first embodiment, since the patch and the microstrip line constituting the dual-polarized antenna are provided on one dielectric layer 7, the structure is simplified and the fabrication is facilitated. There are advantages. That is, when the transmission frequency band antenna 1 is processed by the etching process, the reception frequency band antenna 3 can be processed at the same time. Since the array directivity forming feed circuit prepared for each polarization may be arranged on the same plane as the above-mentioned antenna element, not only the transmitting / receiving antenna but also the feed circuit can be processed at the same time. it can. As a result, a dual-polarized antenna that is easy to design, low-cost, and suitable for mass production can be obtained.

FIG. 3 is a configuration diagram of a dual-polarization antenna according to a second embodiment of the present invention. Here, vertical polarization,
The point of transmission using horizontal polarization is the first embodiment (FIG. 1,
It differs from that of FIG. 2). In FIG. 3, 101 is a transmission frequency band antenna, and 102 is a transmission frequency band antenna 1.
01, a vertical polarization feed line; 103, a horizontal polarization feed line of the transmission frequency band antenna 101; 104, a reception frequency band antenna; 105, a reception frequency band antenna 10;
Reference numeral 4 denotes a vertical polarization feed line, reference numeral 106 denotes a horizontal polarization feed line of the reception frequency band antenna 104, reference numeral 107 denotes a vertical polarization transmission / reception shared feed line, and reference numeral 108 denotes a horizontal polarization transmission / reception shared feed line. That is, the horizontal polarization feed line 103 and the horizontal polarization transmission / reception common feed line of the transmission frequency band antenna are added to the configuration of FIG. Is drawn out at a right angle from substantially the center of the left side of the antenna, bent at a right angle, and extended downward.
6 together with the horizontal polarization transmission / reception shared power supply line 108.

FIG. 4 shows the results of actual measurement of the return loss characteristic and the polarization-to-polarization isolation (polarization plane coupling amount) in the dual-polarization antenna of FIG. Each element antenna operates independently, and the degree of polarization plane coupling is -30 dB or less. This is practically advantageous because it is smaller than the degree of polarization plane coupling of the antennas of FIGS.

It is needless to say that the dual-polarized antenna according to the second embodiment can be used for a system that uses only one of the vertical polarization and the horizontal polarization for transmission.

FIG. 5 is a configuration diagram of a dual-polarized antenna according to a third embodiment of the present invention. Here, the first and second
Is different from that of the first embodiment (FIGS. 1 and 2). In FIG. 5, 201 is a rectangular patch antenna that is sensitive to vertical polarization at the transmission frequency, 202 is a microstrip line that is a feed line for vertical polarization of the rectangular patch antenna 201, 203 is sensitive to horizontal polarization at the transmission frequency, At the receiving frequency, a rectangular patch antenna sensitive to vertical polarization, 204 is a microstrip line which is a feed line for horizontal polarization of the rectangular patch antenna 203, and 205 is a microstrip line which is a feed line for vertical polarization of the rectangular patch antenna 203 Reference numeral 206 denotes a microstrip line which is a vertically polarized transmission / reception shared feed line.

According to this configuration, since the resonance frequency of the rectangular patch antenna differs for each excited polarization plane, there is an effect that a large amount of polarization plane coupling can be secured.

FIG. 6 is a configuration diagram of a dual-polarized antenna according to a fourth embodiment of the present invention. Here, the first and second
Is different from that of the second embodiment (FIG. 3). In FIG. 6, reference numeral 301 denotes a rectangular patch antenna that is sensitive to vertical polarization at the transmission frequency and is sensitive to horizontal polarization at the reception frequency; 302, a microstrip line that is a feed line for the vertical polarization of the rectangular patch antenna 301; A microstrip line, which is a feed line for horizontal polarization of the rectangular patch antenna 301, 304 is a rectangular patch antenna that is sensitive to horizontal polarization at the transmission frequency and is sensitive to vertical polarization at the reception frequency, and 305 is a horizontal patch antenna that is horizontal to the rectangular patch antenna 304. Microstrip line, which is a feed line for polarization, 3
Reference numeral 06 denotes a microstrip line which is a feed line for vertical polarization of the rectangular patch antenna 304, reference numeral 307 denotes a microstrip line which is a feed line shared for vertical polarization transmission and reception, and reference numeral 308.
Is a microstrip line which is a feed line shared for horizontal polarization transmission and reception.

According to this configuration, since the resonance frequency of the rectangular patch antenna differs for each of the excited polarization planes, there is an effect that a large polarization plane coupling amount can be secured.

It is needless to say that the dual-polarized antenna according to the fourth embodiment can also be used for a system using only one of the vertical polarization and the horizontal polarization for transmission.

FIG. 7 is a configuration diagram of a dual-polarized antenna according to a fifth embodiment of the present invention. Here, the dual-polarized antenna is at + 45 ° with respect to the antenna array axis (vertical direction).
And an oblique polarization having an inclination of −45 ° are used for transmission and reception with each polarization.

In FIG. 7, reference numeral 401 denotes a rectangular patch antenna which is a transmission frequency band antenna, 402 denotes a microstrip line which is a feed line for + 45 ° oblique polarization of the transmission frequency band antenna 401, and 403 denotes a transmission frequency band antenna. Microstrip line 401 is a feed line for obliquely polarized light at −45 °, 404 is a rectangular patch antenna that is an antenna for a reception frequency band, and 405 is a micro feed line that is a feed line for + 45 ° oblique polarization of the antenna 404 for the reception frequency band. A strip line, 406 is a microstrip line which is a feed line for obliquely polarized light at −45 ° of the reception frequency band antenna 404, 407 is a microstrip line which is a feed line for transmitting and receiving obliquely polarized light at + 45 °, and 408 is −45.
° It is a microstrip line that is a feed line for oblique polarization transmission and reception.

According to this configuration, regarding the transmitting frequency band antenna 401 and the receiving frequency band antenna 404,
Since the portions contributing to radiation do not face each other, there is an effect that electrical coupling between elements can be suppressed.

FIG. 8 is a configuration diagram of a dual-polarized antenna according to a sixth embodiment of the present invention. Here, the first and second
Is different from that of the fifth embodiment (FIG. 7). In FIG. 8, reference numeral 501 denotes a transmission frequency band at + 45 °.
A rectangular patch antenna sensitive to oblique polarization and sensitive to −45 ° oblique polarization in the reception frequency band, 502 is sensitive to −45 ° oblique polarization in the transmission frequency band, and + 45 ° in the reception frequency band. ° A rectangular patch antenna having sensitivity to oblique polarization, and 503 is a + of the rectangular patch antennas 501 and 502.
A microstrip line, which is a 45 ° obliquely polarized feed line, 504 is a minus line of the rectangular patch antennas 501 and 502.
This is a microstrip line that is a 45 ° obliquely polarized power supply line.

According to this configuration, there is an advantage that the effect of the fourth embodiment is obtained in addition to the effect of the fifth embodiment. That is, since the portions contributing to radiation do not face each other, electrical coupling between the elements can be suppressed, and since the resonance frequency of the rectangular patch antenna differs for each excited polarization plane, a large amount of polarization plane coupling is secured. it can.

FIG. 9 is a configuration diagram of a dual-polarized antenna according to a seventh embodiment of the present invention. This dual-polarized antenna is the same as the dual-polarized antenna of the second embodiment (FIG.
What is rotated in the vertical direction is arranged in the vertical direction. In FIG. 9, reference numeral 50 denotes a microstrip line which is a vertically polarized transmission / reception shared feed line, and reference numeral 60 denotes a horizontally polarized transmission / reception shared feed line.

According to this configuration, there is an effect that the space in the width direction of the dielectric layer can be effectively used.

It should be noted that the dual-polarization antenna according to the second, fourth, fifth, and sixth embodiments (FIGS. 3, 6, 7, and 8) has a 90 ° angle.
The same effect can be obtained by rotating and arranging.

It is needless to say that the dual-polarized antenna according to the seventh embodiment can be used for a system using only one of the vertical polarization and the horizontal polarization for transmission.

Furthermore, the first and third embodiments (FIG. 1,
When the dual-polarization antennas according to 2, 5) are arranged by rotating them by 90 °, the same effects as those of the seventh embodiment can be obtained if the antennas are used for a polarization diversity system that transmits with horizontal polarization.

[0045]

The present invention exhibits the following excellent effects.

(1) Since the first and second antennas and the feed lines for each polarization are provided on a single dielectric substrate, the structure is simplified and the manufacture is facilitated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a dual-polarization antenna according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of the dual-polarization antenna of FIG.

FIG. 3 is a configuration diagram of a dual-polarized antenna according to a second embodiment of the present invention.

FIG. 4 is a characteristic diagram showing the results of actual measurement of return loss characteristics and polarization-to-polarization isolation (polarization plane coupling amount) in the dual-polarization antenna of FIG. 3;

FIG. 5 is a configuration diagram of a dual-polarized antenna according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of a dual-polarization antenna according to a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram of a dual-polarization antenna according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a dual-polarization antenna according to a sixth embodiment of the present invention.

FIG. 9 is a configuration diagram of a dual-polarization antenna according to a seventh embodiment of the present invention.

FIG. 10 is a configuration diagram of a conventional antenna that operates at different frequencies due to multilayering.

FIG. 11 is a configuration diagram of a conventional antenna that operates at different frequencies with a wide band by multilayering.

[Explanation of symbols]

 Reference Signs List 1 antenna for transmission frequency band (first antenna) 2 feed line for vertical polarization (feed line) 3 antenna for reception frequency band (second antenna) 4 feed line for vertical polarization (first feed line) 5 Feeding line for horizontal polarization (second feeding line) 6 Feeding line for vertical polarization transmission / reception (connection point) 7 Dielectric layer

Claims (8)

[Claims] 1. A dual-polarization antenna for transmitting and receiving at different frequencies, a first antenna capable of independently exciting a polarization plane A and a polarization plane B orthogonal to the polarization plane A, and a polarization plane A and a polarization plane B and a second antenna capable of independently exciting B are arranged adjacent to each other, a feed line for feeding power to each antenna is connected to a common coupling point, and a polarization plane A
And a second feed line for exciting the polarization plane B are provided independently of each other. 2. When the impedance on the antenna side is viewed from the coupling point, the second frequency at the resonance frequency of the first antenna is
2. The dual-polarized antenna according to claim 1, wherein the impedance of the antenna is substantially open, and the impedance of the first antenna is substantially open at the resonance frequency of the second antenna. 3. The transmission and reception on the same polarization plane are performed using different antennas.
Or the dual-polarization antenna according to 2. 4. The dual-polarized antenna according to claim 1, wherein a dimension of the first antenna is different from a dimension of the second antenna. 5. The antenna according to claim 1, wherein the first antenna is strongly sensitive to the transmission frequency band power on the polarization plane A and is hardly sensitive to the reception frequency band power, and the second antenna is the reception frequency band for each of the polarization plane A and the polarization plane B. The dual-polarized antenna according to any one of claims 1 to 4, wherein the dual-polarization antenna is strongly sensitive to electric power and hardly sensitive to transmission frequency band power. 6. The first antenna is strongly sensitive to the transmission frequency band power and hardly sensitive to the reception frequency band power for each of the polarization plane A and the polarization plane B, and the second antenna is the polarization plane A and the polarization plane The dual-polarized antenna according to any one of claims 1 to 4, wherein each of B is strongly sensitive to the reception frequency band power and hardly sensitive to the transmission frequency band power. 7. The first antenna is strongly sensitive to transmission frequency band power on a polarization plane A and hardly sensitive to reception frequency band power, is strongly sensitive to a reception frequency band power on a polarization plane B, and is highly sensitive to transmission frequency band power. , The second antenna is hardly sensitive to the reception frequency band power on the polarization plane B, strongly sensitive to the reception frequency band power on the polarization plane A, and hard to be sensitive to the transmission frequency band power. The dual-polarized antenna according to any one of claims 1 to 4. 8. The antenna according to claim 1, wherein the first antenna is strongly sensitive to the transmission frequency band power on the polarization plane A and hardly sensitive to the reception frequency band power, and is strongly sensitive to the reception frequency band power on the polarization plane B and the transmission frequency band power. The second antenna is strongly sensitive to the transmission frequency band power on the polarization plane B and is hardly sensitive to the reception frequency band power, and is strongly sensitive to the reception frequency band power on the polarization plane A and the transmission frequency band power. The dual-polarization antenna according to any one of claims 1 to 4, wherein the dual-polarization antenna is hardly responsive to the following.