JPH11168323A - Multi-frequency antenna device and multi-frequency array antenna device using multi-frequency sharing antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device which radiates large power and which can be miniaturized in height/width directions by providing plural logarithm period dipole parts excited from two parallel lines transmitting radio waves from a micro strip line in accordance with respective necessary frequency bands and reflecting the radiated radio wave of the logarithm period dipole part so as to radiate the radio wave. SOLUTION: An input signal is inputted to the micro strip line 12 from a feeder circuit through a connector. The input signal is transmitted through the micro strip line 12 and it is transmitted through a balun 13. Then, it is naturally converted into a signal transmitted through the two parallel lines 14. The converted signal is transmitted through the two parallel lines 14 but a metallic reflection board 17 and the two parallel lines 14 are insulated at a position where they cross the metallic reflection board 17 by a hole provided on the metallic reflection board 17. The signal is transmitted and it is excited in the first necessary frequency band at first and it is not resonated and is not excited in the second necessary frequency band.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-frequency radar system and a flattened antenna device used for communication and the like.

[0002]

2. Description of the Related Art FIG. D. Kraus
Author, "ANTENNAS-Second Edition"
n- ", McGrawHill, p. 708, 1988
1 is a configuration diagram of a conventional log-periodic dipole shown in FIG. In the figure, 1 is a dipole element, 2a is a coaxial line, 2b is a conductor, and both constitute two parallel lines. The dipole element 1a is connected to the coaxial line 2a, and the dipole element 1b is connected to the conductor 2b. Reference numeral 2c denotes a core wire of the coaxial line 2a. 3 is an input terminal. Reference numeral 4 denotes a feed point of the log-periodic dipole, and the core 2c of the coaxial line 2a is electrically connected to the conductor 2b.

The operation of the log-periodic dipole will be described. The signal fed from the input terminal 3 propagates through the coaxial line 2 a and reaches the feed point 4. At the feeding point 4, the current flowing through the core wire 2c of the coaxial line 2a is transmitted to the connected conductor 2b, and the current flowing through the outer conductor of the coaxial line 2a is totally reflected, the phase is inverted, and flows toward the input terminal 3. Then, power is supplied to the dipole element 1a and the dipole element 1b, respectively.

[0004]

In this conventional power supply structure for a log-periodic dipole, when a metal reflector is used to improve gain or the like, the metal reflector is placed in the back lobe direction, that is, on the low frequency band side of the log-periodic dipole. And parallel 2
It must be installed perpendicular to line 2. In this case, the distance of each dipole element from the metal reflector in the log-periodic dipole becomes shorter in inverse proportion to the wavelength toward the lower frequency band side. On the other hand, the log-periodic dipole is an antenna on which a backward wave whose excitation phase of each dipole element is delayed toward the feeding point is placed, and the radiation direction is toward the feeding side. In the dipole element on the low frequency band side distant from the feeding point 4, the backward wave may not be applied and may be excited as a simple dipole. In this case, since the dipole element on the low frequency band side also radiates in the direction of the metal reflector, the radiation pattern is affected by the reflected wave, and there is a problem that the radiation characteristics as a logarithmic periodic dipole are disturbed.

For example, when the first and second required frequency bands which are about three times apart from each other are satisfied, the first and second required frequency bands are conventionally used.
For example, a second dedicated antenna is used separately, or one antenna that satisfies a wide frequency band including the first and second required frequency bands is used.

However, in the former example, the first and second
Is used as an element antenna of the array antenna, two types of element antennas are arranged on the array aperture surface. Here, assuming that the first required frequency band is a relatively high frequency band, a part of the radiation from the first required frequency band dedicated antenna is transmitted to the second required frequency band dedicated antenna disposed in the vicinity thereof. It is conceivable to combine and re-radiate, and there is a problem that radiation characteristics are disturbed in the first required frequency band. An example of the latter antenna is a conventional log-periodic dipole shown in FIG. 14, but there is a problem that the antenna size becomes large to satisfy a wide frequency band, and an element antenna of an array antenna which requires beam scanning such as a radar. In this case, it is difficult to apply this antenna because there is a restriction that the antenna is downsized due to the limitation of the element spacing.

On the other hand, in order to make up for these difficulties, there have been proposed some antennas which can satisfy two frequencies separated in a frequency band and can be downsized. For example, JP-A-8-18
No. 1536 discloses a dual frequency corner antenna.
There is a type in which a metal reflector is arranged perpendicular to the main beam direction of a dipole antenna for dual frequency use. This is achieved by printing the first and second half-wave dipole antennas on a substrate so that the distance from the corner reflector in the vertical direction is 1/5 of the wavelength of each of the above frequencies. It is arranged in.

Japanese Patent Application Laid-Open No. 8-8637 discloses a printed antenna combining a logarithmic periodic dipole and a shortened dipole as a dual frequency antenna. This is a parallel dipole that feeds a log-periodic dipole that satisfies a relatively high frequency band out of two frequencies, a shortened dipole that satisfies a lower frequency band is connected in series to two parallel lines, and power is supplied from the log-periodic dipole side. It is.

One of the conventional examples described above is disclosed in Japanese Patent Laid-Open No.
In the dual frequency antenna described in Japanese Patent No. 1536,
A dipole is applied to the radiating part. If the required frequency bandwidth is wide, the dipole may not be able to cover the entire frequency band.

In the dual-frequency antenna described in Japanese Patent Application Laid-Open No. 8-8637, a shortened dipole is applied to a high frequency band, and the antenna is miniaturized. May not be satisfactory if the bandwidth is wide.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem. In a plurality of frequency bands, the radiation forward from a dipole is provided in front of the arranged metal reflectors (the multi-frequency common use of the present invention). In the antenna device, the radiation in this direction corresponds to unnecessary radiation) and the radiation from the image by the metal reflector (radiation by reflection on the metal reflector) radiates a large power with the same phase, and the antenna device It is an object of the present invention to obtain a multi-frequency antenna device that can be downsized in the height direction and the width direction. It is another object of the present invention to obtain a multi-frequency antenna device that can be planarized by supplying power to two parallel lines from a microstrip line via a balun. Further, it is another object of the present invention to obtain an array antenna device that can operate as an orthogonal two-polarization or circular polarization array by using the multi-frequency antenna as an element antenna.

[0012]

According to a first aspect of the present invention, there is provided a multi-frequency antenna device comprising a dielectric substrate, strip conductors and ground conductors provided on both sides of one end of the dielectric substrate, and connected to a feed circuit. A microstrip line, a ground conductor and a part of the ground conductor of the microstrip line formed in a tapered shape and the strip conductor,
A balun that functions as a balanced-unbalanced converter, and a strip conductor that is connected to one end of each of the baluns on both sides of the dielectric substrate and extends, and propagates radio waves from the microstrip line via the balun. The two parallel lines, and the microstrip line and the balun are arranged on the rear side of the parallel line and the dipole element described below is arranged on the front side thereof. A metal reflector disposed insulated from the two wires, and a plurality of dipole elements formed in pairs on both surfaces of the dielectric substrate by strip conductors extending alternately from the respective strip conductors of the parallel two wires. And at least two or more required frequency bands from a relatively high frequency band to a low frequency band in order from the one closer to the metal reflector. A plurality of log-periodic dipole sections which are sequentially arranged at a distance from the metal reflector of about 1/4 wavelength at the center frequency of each frequency band and which are excited from the two parallel wires corresponding to each of the required frequency bands. Wherein the radio wave radiated from the log-periodic dipole portion is reflected by the metal reflection plate to radiate the radio wave forward.

According to another aspect of the present invention, at least one strip conductor of a plurality of dipole elements in at least one of the plurality of log-periodic dipole portions is formed in a meander shape. It has a log-periodic meander dipole section as an element.

The multi-frequency antenna according to a third aspect of the present invention is the multi-frequency antenna, wherein the log-periodic dipoles are disposed adjacent to each other, the log-periodic meander dipoles are disposed between the log-periodic dipoles or the logarithm. An open stub having a line length of about 1/4 wavelength at a center frequency of a relatively high frequency band of the corresponding frequency band was connected in parallel to the two parallel lines between the periodic dipole portion and the logarithmic meander dipole portion. Things.

The multi-frequency antenna according to a fourth aspect of the present invention is the multi-frequency antenna according to the above-mentioned multi-frequency antenna, wherein a matching load or an anti-reflection means made of a radio wave absorbing material is loaded at an end of the two parallel wires. .

According to a fifth aspect of the present invention, there is provided the multi-frequency antenna device according to the fifth aspect, wherein the dipole element and the meander dipole element or the meander dipole elements which are arranged adjacently and have different impedances are different from each other. A transformer formed by changing the line width of the two parallel lines is provided at a necessary portion of the two parallel lines between the two lines to change the line width of the two parallel lines, and the characteristic impedance of the two parallel lines is set as an excitation target. This is matched with the impedance of the dipole element or meander dipole element.

According to a sixth aspect of the present invention, there is provided the multi-frequency antenna device according to any one of the first to fourth aspects, wherein the adjacently arranged dipole elements having different impedances. Forming a portion of the dielectric substrate on which the two parallel lines are formed at necessary portions between the two parallel lines between the and the meander dipole element or between the meander dipole elements by using dielectric materials having different relative dielectric constants; The characteristic impedance of the two parallel wires is changed, and the characteristic impedance of the two parallel wires is matched with the impedance of the dipole element or the meander dipole element to be excited.

According to a seventh aspect of the present invention, there is provided a multi-frequency array antenna device, wherein the multi-frequency antenna device according to any one of the first to sixth aspects is used as an element antenna, and a plurality of the plurality of metal antennas are used for metal reflection. The plates are formed of a common metal reflector and arranged so that they face in the same direction, and the radio waves radiated from each of the element antennas are combined after being reflected by the metal reflector and emit polarized waves in a certain direction. It is.

According to a eighth aspect of the present invention, there is provided a multi-frequency array antenna device, wherein the multi-frequency shared antenna device according to any one of the first to sixth aspects is used as an element antenna, and a plurality of the plurality of metal antennas are used for metal reflection. The plate is formed of a common metal reflection plate and is arranged so as to face two orthogonal directions. Exciting means for making the phases of the radio waves radiated from the element antenna in each of the two orthogonal directions equal to each other is provided. Radio waves radiated from each element antenna are reflected by the metal reflector and then combined to radiate two polarized waves in directions orthogonal to each other.

A multi-frequency array antenna device according to a ninth aspect of the present invention is the multi-frequency array antenna device according to the eighth aspect, wherein the element antenna in each of the two orthogonal directions is used in place of the excitation means. It is provided with excitation means for shifting the phases of the radio waves radiated from the device by 90 degrees from each other, and radiates circularly polarized waves.

According to a tenth aspect of the present invention, there is provided the multi-frequency array antenna device according to the eighth aspect of the present invention, wherein the exciting means is replaced with an element antenna in each of the two orthogonal directions. The excitation means for shifting the phases of the radiated radio waves in a specific frequency band of two or more required frequency bands from each other by 90 degrees, and making the phases of the radiated radio waves in the other frequency bands in-phase, Radiates circularly polarized waves, and, in the other frequency bands, two polarized waves in directions orthogonal to each other.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In describing the embodiment, a dual-frequency antenna device will be described as an example of a multiple-frequency antenna device for simplicity of description. The same applies to the following embodiments. In this case, it is assumed that the first required frequency band is relatively higher than the second required frequency band. FIG. 1 is a diagram illustrating a configuration of a multi-frequency antenna device according to Embodiment 1 of the present invention as viewed from above a dielectric substrate. FIG. 2 is a perspective view illustrating the configuration of the multi-frequency antenna device according to Embodiment 1 of the present invention. 1 and 2, reference numeral 11 denotes a dielectric substrate, 12a denotes a strip line provided on one surface of the dielectric substrate 11, 12b denotes a ground pattern provided on the other surface of the dielectric substrate 11, and 12 denotes a strip line and a ground. A microstrip line composed of the pattern 12b, 13a is a ground pattern in which a part of the ground pattern 12b is tapered, and 13 is composed of the ground pattern 13a and the strip line 12a as a balanced-unbalanced converter. A functioning balun, 14 is a parallel line having the same line width as the strip line 12a and provided on both surfaces of the dielectric substrate 11, and 15 is a band in which the first required frequency band is relatively higher than the second required frequency band. The log-periodic dipole section 16 provided on the dielectric substrate 11 for excitation in the first required frequency band, Body substrate 11
A log-periodic dipole section provided at the second required frequency band provided above, 17 is a metal reflector disposed perpendicular to the dielectric substrate 11 and the two parallel lines 14, and 18 is a metal reflector 1
This is a means for avoiding electrical continuity with the two parallel wires 14 provided at 7, and is a hole in this example.

The dipole elements of the log-periodic dipole section 15 for exciting in the first required frequency band and the log-periodic dipole section 16 for exciting in the second required frequency band are alternately arranged on both sides of the dielectric substrate 11 as shown in the figure. Is provided. The microstrip line 12 and the balun 13 are connected to one side of the metal reflection plate 17 on the back side (the metal reflection plate 17).
The dipole element direction on the other side of the front is the front)
To place.

Next, the operation will be described. First, a case in which operation is performed in the second required frequency band, which is a relatively low frequency band, will be described. Although not shown in FIGS. 1 and 2, the input signal is input from the power supply circuit to the microstrip line 12 via the connector. The input signal propagates through the microstrip line 12 and is converted to a signal that propagates through the parallel two wires 14 by way of the balun 13 connected thereto. The converted signal is a parallel two line 1
4, the metal reflector 17 and the parallel two wires 14 are insulated from each other by a hole 18 provided on the metal reflector 17 at a position where the metal reflector 17 intersects, and the signal propagates. Log-periodic dipole unit 1 to be excited in the required frequency band
5, but in the second required frequency band, each dipole element of the log-periodic dipole unit 15 is a dipole having a length shorter than the wavelength, and does not resonate and is not excited. Therefore, the signal further propagates through the two parallel lines 14 and reaches the log-periodic dipole section 16 which is excited in the second required frequency band. In the log-periodic dipole section 16, the second
There are dipole elements that resonate in the required frequency band, and these dipole elements are excited to radiate radio waves toward the power supply side, that is, toward the metal reflector 17. This is because the log-periodic dipole is a kind of backward waveform antenna, and the radiation direction is to the feed side. The dipole element in the portion where the backward wave is difficult to ride works as a mere dipole, and may radiate a little forward. However, the log-periodic dipole section 16 is arranged at a position of about 1/4 wavelength in the second required frequency band from the metal reflector 17, and the radio wave radiated in the power supply side direction is reflected by the metal reflector 17, It is combined in phase with some forward radiated radio waves from the dipole element that has simply functioned as a dipole and radiated forward without attenuation.

Next, a description will be given of a case of operating in the first required frequency band which is a relatively high frequency band. in this case,
Log-periodic dipole unit 1 excited in the first required frequency band
5 is the same as described above up to the point where the input signal propagates through the two parallel lines 14 and reaches. In the first required frequency band, resonating dipole elements exist in the log-periodic dipole section 15, and these dipole elements are excited to radiate radio waves to the power supply side. At this time, almost all of the input signal is consumed by the log-periodic dipole unit 15 and does not propagate to the log-periodic dipole unit 16. The radiated radio wave is reflected by the metal reflector and radiated forward.

As described above, in the multi-frequency antenna device according to the present embodiment, the portion excluding the metal reflector can be patterned on the dielectric substrate 11 to form a planar structure, and the size and workability can be reduced. Are better.

In the multi-frequency antenna device according to the present embodiment, a radio wave is first radiated in the direction of the metal reflector 17 and the radio wave is radiated forward in a desired direction by utilizing the reflection from the metal reflector 17. However, the log-periodic dipole portions 15 and 16 for exciting in the first and second required frequency bands are respectively set at positions separated from the metal reflector 17 by 1/4 wavelength in the first and second required frequency bands. Because
In the first and second required frequency bands, respectively, the radiation from the image by the metal reflector 17 and the slightly radiated radio waves to the front generated by the difficulty of the backward wave from the log-periodic dipole portions 15 and 16 are in phase. And large power can be radiated forward without being attenuated.

When large power is radiated forward using the radiation from the image by the metal reflector 17, it is necessary to arrange the feeding position of the multi-frequency antenna device of the present embodiment on the metal reflector 17 side. . In order to realize this structure, in the multi-frequency antenna device according to the present embodiment, power can be supplied to the parallel two wires 14 via the balun 13 by the microstrip line 12, and on the dielectric substrate 11 as described above. It can be made into a plane by patterning,
Excellent workability. Microstrip line 1
2 and the balun 13 are disposed on the back side of the metal reflection plate 17 (the side opposite to the log-periodic dipole), so that radio waves from the log-periodic dipole 15 or 16 and unnecessary radiation from the microstrip line 12 and the balun 13 Interference can be reduced.

Each of the first and second required frequency bands is formed by a log-periodic dipole, so that each band can be widened. Further, the first and second required frequency bands separated from each other are combined into a wide band. Considering that the size of the log-periodic dipole in the antenna height direction (parallel two-line extending direction) of the logarithmic-periodic dipole when satisfied with the conventional log-periodic dipole shown in FIG. Then the size can be reduced.

The dipole elements of the log-periodic dipole section 15 or 16 are shown in FIGS. 1 and 2 as being arranged perpendicular to the two parallel lines 14.
For example, a V-shaped dipole similar to FIG. 4 described later may be used.

Embodiment 2 FIG. 3 is a diagram illustrating the configuration of a multi-frequency antenna device according to Embodiment 2 of the present invention (here, an example of a dual-frequency antenna device) viewed from above a dielectric substrate. In the figure, reference numeral 21 denotes a meander dipole element having a meander shape, and reference numeral 22 denotes a logarithmic-period meander dipole section including the meander dipole element 21 and excited in a second required frequency band.

The operation of the multi-frequency antenna device according to the present embodiment is the same as that of the first embodiment described above, and will not be described here. The advantages of the multi-frequency antenna device according to the present embodiment are as follows in addition to the items described in the first embodiment. When the first required frequency band is relatively higher than the second required frequency band, a logarithmic periodic dipole unit 15 that excites in the first required frequency band, and a logarithm that excites in the second required frequency band Of all the dipole elements of the periodic meander dipole section 22, the dipole element having a relatively large resonance frequency and a relatively low resonance frequency is replaced with the meander dipole 21, so that the size can be reduced in the antenna width direction.

In order to realize an array antenna that shares two frequencies of the first and second required frequency bands on the same aperture, where the first required frequency band is a relatively high frequency band, the respective required frequencies If the element antenna is different in the band, the array radiation pattern in the first required frequency band, which is a high frequency band, is disturbed due to blocking by the element antenna operating in the second required frequency band or the influence of re-radiation. In order to prevent these, it is necessary to arrange the multi-frequency shared element antennas that are fed in the same manner on the aperture, and even if the small multi-frequency shared antenna device shown in the present embodiment requires a narrow interval, It can be arranged and the effectiveness of being an element antenna is great.

The meander dipole element 21
Is arranged perpendicular to the two parallel lines 14 in FIG. 3, but may be a meander dipole element 21 formed in a V shape as shown in FIG. 4, for example.

Further, meander dipole element 2
The number of 1 is arbitrary. For example, all the dipole elements of the logarithmic periodic meander dipole section 22 may be meander dipole elements.

Embodiment 3 FIG. 5 is a diagram illustrating the configuration of a multi-frequency antenna device according to Embodiment 3 of the present invention (here, an example of a dual-frequency antenna device) viewed from above a dielectric substrate. FIG. 6 shows a straight line A- shown in FIG.
It is sectional drawing in A '. In FIGS. 5 and 6, reference numeral 31 denotes an excitation in the first required frequency band provided on the dielectric substrate 11 when the first required frequency band is relatively higher than the second required frequency band. A stub having an open end connected in parallel to two parallel wires 14 between the log-periodic dipole unit 15 and a log-periodic dipole unit 16 that is excited on the second required frequency band similarly provided on the dielectric substrate 11, Its total length is 1/4 wavelength at the center frequency of the first required frequency band. A point P is a connection point of the stub 31 to the two parallel lines 14.

Next, the operation of the multi-frequency antenna device according to the present embodiment will be described. Microstrip line 12
The method of propagating the input signal to the log-periodic dipole unit 15 excited at the first required frequency is the same as in the first embodiment, and a description thereof will be omitted. When operating in the second required frequency band, the log-periodic dipole unit 1
5 does not radiate, so the signal propagating to the log-periodic dipole unit 15 propagates through the parallel two wires 14 without attenuation,
The stub 31 reaches the connection point P. The stub 31 has an open end, and the entire length of the stub 31 is １ ／ wavelength at the center frequency of the first required frequency band. Looks shorter than compared. Thus, at the connection point P, the signal propagated without any influence in the second required frequency band passes through the connection point P as it is and propagates to the log-periodic dipole unit 16 excited at the second required frequency. Then, a predetermined dipole element of the log-periodic dipole section 16 resonates and emits a radio wave. The radiated radio wave is reflected by the metal reflector 17 and radiated forward.

On the other hand, when the multi-frequency antenna device according to the present embodiment is operating in the first required frequency band, the signal transmitted through the parallel two-wires 14 is logarithmically excited at the first required frequency. In the periodic dipole section 15, a predetermined dipole element resonates and emits a radio wave. The radiated radio wave is reflected by the metal reflector 17 and radiated forward. At this time, the signal that did not match the dipole element and could not be radiated further propagates through the two parallel lines 14 and reaches the connection point P. Here, the entire length of the stub 31 is １ ／ wavelength at the center frequency of the first required frequency band, and the tip is in an open state. Therefore, at the intersection P, it looks almost short-circuited in the first required frequency band. For this reason, a signal that has propagated through the parallel two wires 14 without being completely radiated in the log-periodic dipole unit 15 does not propagate beyond the connection point P. At the connection point P, the signal is completely reflected because it looks like a short circuit, but the signal propagated without being completely radiated at the log-periodic dipole unit 15 is small, so that the influence of the reflected wave from the connection point P is not a problem. is there.

In the above-described multi-frequency antenna apparatus according to the present embodiment, when operating in the first required frequency band, which is a relatively high frequency band, the log-periodic dipole unit excited at the first required frequency The signal transmitted through the parallel two lines 14 to the connection point P without being completely radiated at 15 is a second signal.
The higher-order mode is excited in the dipole element of the log-periodic dipole section 16 excited at the required frequency to emit unnecessary radio waves, causing interference with the original radio waves radiated from the log-periodic dipole section 15 and disturbing the radiation pattern. Can be prevented.

It is needless to say that the advantages shown in the first embodiment and the second embodiment using the meander dipole element are satisfied also in the multi-frequency antenna device shown in the third embodiment.

Embodiment 4 FIG. FIG. 7 is an explanatory diagram of a configuration of a multi-frequency antenna device according to Embodiment 4 of the present invention (here, an example of a dual-frequency antenna device) viewed from above a dielectric substrate. FIG. 8 is a sectional view taken along line AA ′ shown in FIG. 7 and 8, reference numeral 41 denotes two parallel lines extending from the log-periodic dipole section 16 excited in the second required frequency band toward the substrate end of the dielectric substrate 11.
Reference numeral 2 denotes a matching load loaded to match the characteristic impedance of the parallel two wires 41 at the end of the parallel two wires 41, or the installation of an absorbing material such as an absorbing paint.

Next, the operation of the multi-frequency antenna device according to the fourth embodiment will be described. The principle of radiating radio waves in the first and second required frequency bands is the same as that described in the first embodiment, and therefore will not be described here. Now, by loading a matching load 42 having the same value as the characteristic impedance of the parallel two wires 41 at the end of the parallel two wires 41 extending from the logarithmic periodic dipole 16 toward the substrate end, or by attaching an absorbing paint or the like, the second The signal which cannot be radiated due to the mismatch between the dipole element in the log-periodic dipole section 16 and the parallel two-wire 14 excited in the required frequency band propagates through the parallel two-wire 41, and finally the parallel two-wire 41 Is absorbed by the matching load 42 loaded on the terminal end of the terminal or by the absorbing paint or the like. This makes it possible to suppress the generation of unnecessary radiation due to the reflected wave at the end of the parallel two wires 14.

Further, it goes without saying that the advantages shown in the first, second and third embodiments are satisfied also in the multi-frequency antenna device shown in the present embodiment.

Embodiment 5 FIG. FIG. 9 is a configuration diagram of a multi-frequency antenna device (in this example, a dual-frequency antenna device) according to Embodiment 5 of the present invention as viewed from above a dielectric substrate. In FIG. 9, reference numeral 51 denotes a dipole element having the lowest resonance frequency provided on the dielectric substrate 11;
Is a meander dipole element having the highest resonance frequency provided on the dielectric substrate 11. Numeral 53 denotes a parallel two line which has a line width which is sequentially widened and functions as a transformer formed by changing the line width. Numeral 54 denotes a line width which is sequential in the same manner as the parallel two line 53 which functions as a transformer. Are the two parallel lines acting as transformers formed by changing the line width. The point Q is a point on the parallel two line 14 where the parallel two line 53 starts.

The dipole element 51 and the meander dipole element 52 are relatively low frequency bands.
It is not necessary that both exist in the log-periodic meander dipole section 22 excited in the required frequency band. For example, the dipole element 51 is the longest in the log-periodic dipole section excited in the first required frequency band. Dipole element, meander dipole element 52
May be the shortest dipole element in the log-period meander dipole section excited in the second required frequency band. In this case as well, the position of the point Q where the parallel two lines 53, whose line widths are sequentially increased, starts from the log-periodic dipole section excited in the first required frequency band and the log-periodic meander excited in the second required frequency band. It is a point between the dipole.

Next, the operation of the multi-frequency antenna device shown in this embodiment will be described. The principle of radiation of radio waves in the first and second required frequency bands is described in the first embodiment.
The description is omitted here because it is the same as that shown in FIG. When a dipole element and a meander dipole element are used, for example, the impedances of the dipole element 51 and the meander dipole element 52 are different. Generally, the impedance of the meander dipole element 52 is lower than that of the dipole element 51. Therefore, as shown in FIG. 9, the characteristic impedance of the two parallel wires matching the respective elements differs between the dipole element 51 and the meander dipole element 52, and the parallel two wires 14 from the point Q between these elements.
The width of the line is sequentially increased, and the parallel two lines 53 having the function as a transformer can be provided to eliminate the mismatch between the meander dipole element 52 and the parallel two lines. Furthermore, a parallel two-wire 54 whose line width is sequentially widened to have a function as a transformer in order to have a function as a transformer in order to obtain a parallel two-line matching with the meander dipole element disposed after the meander dipole element 52 is interposed between the meander dipole elements. Connected. As a result, the radiation efficiency can be increased by matching the two parallel lines with each element, and the generation of unnecessary radiation due to reflection from the end of the two parallel lines can be reduced.

The meander dipole element 52
When the impedances of the meander dipole elements arranged thereafter are substantially the same, it is not necessary to provide the parallel two wires 54 whose line widths are sequentially widened in order to have a function as a transformer. After 53, two parallel lines having a constant line width may be connected.

Also, due to the impedance characteristics of the dipole element and the meander dipole element,
It is also conceivable that the line width of the two parallel lines having the function of a transformer formed by changing the line width is gradually reduced.

Embodiment 6 FIG. FIG. 10 is a diagram illustrating a configuration of a multi-frequency antenna device according to Embodiment 6 of the present invention (here, an example of a dual-frequency antenna device) viewed from above a dielectric substrate. FIG. 11 shows a straight line AA ′ in FIG.
FIG. 10 and 11, reference numeral 61 denotes a dipole element having the lowest resonance frequency provided on the dielectric substrate 11, reference numeral 62 denotes a meander dipole element having the highest resonance frequency also provided on the dielectric substrate 11,
Reference numeral 63 denotes a dielectric having a different relative dielectric constant from the dielectric substrate 11 sandwiched between the two parallel wires 14. Here, an example is shown in which the dielectric 63 is formed of dielectrics 63a and 63b having different relative dielectric constants. A point Q is a point on the two parallel lines 14 at which the dielectrics 63 having different relative dielectric constants start.

The dipole element 61 and the meander dipole element 62 are relatively low frequency bands.
It is not necessary that both exist in the log-periodic meander dipole section 22 excited in the required frequency band. For example, the dipole element 61 is the longest in the log-periodic dipole section excited in the first required frequency band. Dipole element, meander dipole element 62
May be the shortest dipole element in the log-period meander dipole section excited in the second required frequency band. In this case, the position of the point Q between dielectrics having different dielectric constants, which is sandwiched between the two parallel lines 14, is a logarithmic periodic dipole section excited in the first required frequency band and excited in the second required frequency band. It is a point between the logarithmic period meander dipole part.

Next, the operation of the multi-frequency antenna device shown in this embodiment will be described. The principle of radiation of radio waves in the first and second required frequency bands is described in the first embodiment.
The description is omitted here because it is the same as that shown in FIG. In the case of using the dipole element and the meander dipole element, for example, the dipole element 61 and the meander dipole element 62 have different impedances as described in the fifth embodiment. Therefore, as shown in FIG. 11, a dielectric 63 having a relative permittivity different from that of the dielectric substrate 11 is loaded between the point Q between the dipole element 61 and the meander dipole element 62 and the two parallel lines 14. By adjusting the characteristic impedance of the parallel two wires 14 to match the impedance of the meander dipole element 62, the radiation efficiency can be increased, and the generation of unnecessary radiation due to reflection from the parallel two wire ends can be reduced.

As shown in FIG. 11, when the dielectrics 63 having different relative dielectric constants have different impedances of the meander dipole elements disposed after the point Q, the characteristic impedance corresponding thereto is changed by two parallel wires 1.
4 parallel to each meander dipole element
Dielectrics 6 having different relative dielectric constants for matching with line 14
It is more effective to form the layers 3a and 63b and load them while changing the relative dielectric constant. Conversely, when each meander dipole element has substantially the same impedance characteristics, it is only necessary to load a dielectric having a constant relative dielectric constant from the position of point Q.

In the above embodiment, the description has been given by taking the dual-frequency antenna as an example of the multi-frequency antenna device. However, the present invention similarly applies to the antenna device sharing the multi-frequency band of two or more frequencies. It goes without saying that it is applicable.

Embodiment 7 FIG. FIG. 12 is an explanatory diagram of a configuration of an array antenna device using the multi-frequency antenna device according to Embodiment 7 of the present invention as an element antenna. In FIG. 12, reference numeral 71 denotes an element antenna, a multi-frequency antenna according to any of the first to sixth embodiments, and 72 a metal reflector. The element antennas 71 are arranged so as to face in the same direction.

Next, the operation of the array antenna device described in this embodiment will be described. The radiation principle of the element antenna 71 has been described in the first embodiment and will not be described here. The element antennas 71 regularly arranged on the metal reflector 72 so as to face in the same direction are excited, and the radio wave radiated for each element in the direction of the metal reflector 72 is applied to the metal reflector 7.
After being reflected by the antenna 2, a radio wave of a certain direction of polarization having a desired radiation pattern as an array antenna is obtained.

In this case, since a feed circuit composed of a diplexer, a distribution circuit, and the like for exciting each element antenna 71 is configured on the back side of the metal reflection plate 72, radio waves radiated from each element antenna are sent to the feed circuit. No worries.

Also, by using the meander dipole element described in the second embodiment, the element antenna 71
The width of the antenna can be reduced, so that the spacing between the element antennas can be narrowed. In this case, the mutual coupling between the element antennas can be reduced, and the effect on the radiation characteristics of the array antenna can be reduced. Can be reduced.

Embodiment 8 FIG. FIG. 13 is a diagram illustrating the configuration of a multi-frequency array antenna device according to Embodiment 8 of the present invention. The metal reflectors are formed of a common metal reflector 72 and arranged so as to face two orthogonal directions, and the phases of the radio waves radiated from the element antenna 71 in the two orthogonal directions are controlled. A power supply circuit (not shown) that excites and excites the signal is provided behind the metal reflection plate 72, and a multi-frequency common wave that radiates a desired polarization by combining radio waves radiated from each element antenna 71 after being reflected by the metal reflection plate 72. FIG. 3 is an explanatory view of the configuration as viewed from the front of a metal reflector 72 of the array antenna device.

Next, the operation of the multi-frequency array antenna device of the present embodiment will be described. Here, first, orthogonal 2
The operation in the case of radiating the polarized wave, the operation in the case of radiating the circular polarization next, and the circular polarization in a specific frequency band of two or more required frequency bands, and the mutual operation in other frequency bands. The operation in the case of radiating two polarized waves in orthogonal directions will be described. The radiation principle of the element antenna 71 has been described in the first embodiment and will not be described here. For example,
As described in the second embodiment, by using a meander dipole element, it is possible to reduce the size of the antenna in the width direction. Therefore, it is possible to arrange the element antennas 71 so as to face a plurality of directions on the same opening of the array. is there. FIG.
In the multi-frequency array antenna device shown in FIG. 3, element antennas 71 regularly arranged on the metal reflector 72 so as to be orthogonal to each other are arranged from the feeder circuit to the element antennas in each of the two orthogonal directions. Are excited so that the phases of the radiated radio waves become the same, and the radio waves radiated for each element in the direction of the metal reflector 72 are combined after being reflected by the metal reflector 72 and have a desired radiation pattern as an array antenna. Radio waves of two orthogonal polarizations are obtained.

Further, excitation is performed so that the phases of the radio waves radiated from the element antennas in the two orthogonal directions from the feeder circuit are shifted by 90 degrees from each other, and the phases of the signals of the vertical polarization and the horizontal polarization are adjusted. Can be obtained by radiating and synthesizing them in a state shifted by 90 degrees from each other. This can be realized by, for example, providing a hybrid circuit in the feed circuit of the multi-frequency array antenna device or by signal processing.

Further, the phases of the radiated radio waves in a specific frequency band among two or more required frequency bands from the element antennas in two directions orthogonal to each other from the power supply circuit are shifted by 90 degrees from each other, and By exciting the radiated radio waves in the band to have the same phase, it is possible to radiate circularly polarized waves in the specific frequency band and radiate two polarized waves in directions orthogonal to each other in the other frequency band. The power supply circuit in this case is configured by combining, for example, a conventional power supply circuit for generating two orthogonal polarizations and a power supply circuit for generating a circular polarization.

As described above, the multi-frequency antenna device according to any one of the first to sixth embodiments is used as an element antenna, and the plurality of element antennas are arranged so as to be orthogonal to each other. By providing a feed circuit that controls and excites the phase of the radio wave radiated from the element antenna in each direction, two orthogonally polarized waves (for example, horizontally polarized wave and vertically polarized wave) or circularly polarized wave can be radiated. A multi-frequency shared array antenna device is obtained, and a multi-frequency shared array antenna device capable of radiating polarized waves and circularly polarized waves in two orthogonal directions divided into frequency bands is also obtained. A shared array antenna device can be obtained.

[0063]

Since the present invention is configured as described above, it has the following effects.

According to the multi-frequency antenna device of the first aspect, the microstrip is composed of the dielectric substrate, the strip conductor and the ground conductor provided on both surfaces of one end of the dielectric substrate, respectively, and connected to the feed circuit. A balun, which comprises a ground conductor and a strip conductor, wherein a part of the ground conductor of the microstrip line is formed into a tapered shape, and a balun functioning as a balance-unbalance converter, and the balun on both surfaces of the dielectric substrate, respectively. And two parallel lines for transmitting radio waves from the microstrip line via the balun, and the microstrip line and the balun are disposed on the rear side of the strip conductor. The two parallel lines are substantially perpendicular to the dielectric substrate and the two parallel lines so that the following dipole element is disposed on the side. The insulated metal reflector and a plurality of dipole elements formed in pairs on both surfaces of the dielectric substrate with strip conductors extending alternately from the respective strip conductors of the two parallel lines, At least 2 in order from the one closer to the metal reflector
Approximately 1/4 at the center frequency of each frequency band in order from relatively high frequency band to low frequency band of one or more required frequency bands
A plurality of log-periodic dipoles which are arranged at a distance from the metal reflector of the wavelength and are excited from the two parallel lines corresponding to each of the required frequency bands, so that the radiation of the log-periodic dipole is provided. There is an effect that the radio wave is reflected by the metal reflection plate and a radio wave of a large power can be emitted to the front side. In addition, it is possible to form a planar structure by patterning on the dielectric substrate except for the metal reflecting plate, and it is possible to obtain a multi-frequency antenna device that is reduced in size and excellent in workability. Furthermore, since the microstrip line and the balun are arranged behind the metal reflector, the effect of preventing radio waves from the log-periodic dipole from interfering with unnecessary radiation from the microstrip line and the balun can be prevented. is there.

According to the multi-frequency antenna device of the second aspect, at least one of the plurality of dipole elements in at least one of the plurality of log-periodic dipole units is used.
Since the strip conductor is formed in a meander shape to form a meander dipole element as a logarithmic periodic meander dipole, the width of the multi-frequency antenna device can be reduced.

According to the multi-frequency antenna according to the third aspect, between adjacent log-periodic dipole units, between log-periodic meander dipole units, or between a log-periodic dipole unit and a log-periodic meander dipole unit. Are connected in parallel to the two parallel lines of the above, an open stub having a line length of about 1/4 wavelength at a center frequency of a relatively high frequency band of the corresponding frequency band, so that a log-periodic dipole excited in the above frequency band Element or meander that can be prevented from propagating beyond the connection position of the open stub by a signal that has propagated through two parallel lines without being completely radiated at the portion or logarithmic meander dipole portion, and that is excited in a relatively low frequency band Unnecessary radio waves are radiated by exciting higher-order modes in the dipole element. Interference caused is effective to prevent the radiation pattern is disturbed.

According to the multi-frequency antenna device according to the fourth aspect, since a matching load or an anti-reflection means made of a radio wave absorbing material is loaded at the end of the two parallel wires, the two parallel wires are connected to the dipole element or the meander dipole element. The signal which could not be completely radiated due to the mismatch with the signal can be absorbed by the anti-reflection means, and there is an effect that generation of unnecessary radiation due to the reflected wave from the end portion of the two parallel lines is suppressed.

According to the multi-frequency antenna device according to the fifth aspect, the two parallel wires between the adjacent dipole elements having different impedances and the meander dipole elements or between the meander dipole elements are required at the necessary positions. A transformer formed by changing the line width of the two parallel lines is provided to change the line width of the two parallel lines so that the characteristic impedance of the two parallel lines is matched with the impedance of the dipole element or the meander dipole element to be excited. Therefore, it is possible to increase the radiation efficiency and to suppress the generation of unnecessary radiation due to the reflection from the end of the two parallel lines.

According to the multi-frequency antenna according to the sixth aspect of the present invention, the two parallel wires between the adjacent dipole elements having different impedances and the meander dipole elements or between the meander dipole elements at the required positions are described. A portion of the dielectric substrate on which the two parallel lines are formed is formed of dielectrics having different dielectric constants to change the characteristic impedance of the two parallel lines, and the characteristic impedance of the two parallel lines is used to excite the dipole element or meander to be excited. Since the impedance is matched with the impedance of the dipole element, there is an effect that the radiation efficiency can be increased and the generation of unnecessary radiation due to reflection from the end of the two parallel wires can be suppressed.

According to the multi-frequency array antenna device of the present invention, the multi-frequency antenna device according to the present invention is used as an element antenna, and a plurality of the respective antennas are formed of a common metal reflector. The antennas are arranged so that they face in the same direction, and the radio waves radiated from each of the element antennas are combined after being reflected by the metal reflection plate to radiate polarized waves in a certain direction. It is possible to prevent the radio wave from interfering with unnecessary radiation from the microstrip line and the balun, and to obtain a desired single-polarization multi-frequency array antenna device having good radiation characteristics unaffected by the power supply side.

According to the multi-frequency array antenna device according to claims 8 to 10, the multi-frequency array antenna device according to the present invention is used as an element antenna, and the plurality of element antennas are arranged in an orthogonal relationship. By providing a feed circuit that controls and excites the phase of the radio wave radiated from the element antenna in each of the two orthogonal directions, polarization or circular polarization in two orthogonal directions, Thus, there is an effect that a multi-frequency array antenna device capable of radiating two-way polarization and circular polarization can be obtained, and a multi-frequency array antenna device capable of meeting various requirements can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory diagram of a multi-frequency antenna device according to a first embodiment of the present invention.

FIG. 2 is a perspective view for describing the configuration of a multi-frequency antenna device according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram illustrating a configuration of a multi-frequency antenna device according to a second embodiment of the present invention.

FIG. 4 is a configuration explanatory view showing a part of a multi-frequency antenna device according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a configuration of a multi-frequency antenna device according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a configuration of a multi-frequency antenna device according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating a configuration of a multi-frequency antenna device according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view for illustrating a configuration of a multi-frequency antenna device according to a fourth embodiment of the present invention.

FIG. 9 is a structural explanatory diagram of a multi-frequency antenna device according to a fifth embodiment of the present invention.

FIG. 10 is a configuration explanatory diagram of a multi-frequency antenna device according to a sixth embodiment of the present invention.

FIG. 11 is a cross-sectional view illustrating a configuration of a multi-frequency antenna device according to a sixth embodiment of the present invention.

FIG. 12 is a configuration explanatory view of a multi-frequency array antenna device according to a seventh embodiment of the present invention.

FIG. 13 is a configuration explanatory view of a multi-frequency array antenna device according to an eighth embodiment of the present invention.

FIG. 14 is a configuration explanatory view showing a conventional antenna device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dipole element, 2a coaxial line, 2b conducting wire, 2c core line of coaxial line 2a, 3 input terminal, 4 feeding point of logarithmic periodic dipole, 11 dielectric substrate, 12 microstrip line, 12a strip line, 12
b ground pattern, 13 baluns, 13a tapered ground pattern, 14 parallel 2 lines, 15
A log-periodic dipole unit to be excited in the first required frequency band,
16 log-periodic dipole section excited in the second required frequency band, 17 metal reflector, 18 holes, 21 meander dipole element, 22 log-periodic meander dipole section, 31 stub with open end, 32 through hole, 4
DESCRIPTION OF SYMBOLS 1 Parallel 2 line, 42 matching load, 51 Dipole element with the lowest resonance frequency, 52 Meander dipole element with the highest resonance frequency, 53, 54 Parallel 2 line, 61 Dipole element with the lowest resonance frequency, 62 Highest with the resonance frequency Meander dipole element, 63 dielectric, 71 element antenna, 72
Metal reflector.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01Q 1/48 H01Q 1/48 5/01 5/01 9/16 9/16 11/10 11/10 13/26 13/26 19/28 19/28 21/06 21/06 21/08 21/08 21/24 21/24 25/04 25/04 (72) Inventor Toshio Nishimura 2-3-2 Marunouchi 2-chome, Chiyoda-ku, Tokyo Inside Electric Corporation (72) Inventor Shigeru Chikaoka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (10)

[Claims] 1. A microstrip line comprising a dielectric substrate, a strip conductor and a ground conductor provided respectively on both surfaces of one end of the dielectric substrate, and connected to a power supply circuit;
A balun composed of a ground conductor and a strip conductor, wherein a part of the ground conductor of the microstrip line is formed in a tapered shape, and a balun functioning as a balanced-unbalanced converter, and one end of each of the baluns on both surfaces of the dielectric substrate. It consists of strip conductors connected and extending, and two parallel lines for transmitting radio waves from the microstrip line via the balun, and the microstrip line and the balun are arranged on the rear side thereof. A metal reflector that is installed insulated from the dielectric substrate and the parallel two lines substantially perpendicular to the dielectric substrate and the parallel two lines so that the dipole element is arranged, and alternately from the strip conductors of the parallel two lines. It consists of a plurality of dipole elements formed in pairs on both sides of the dielectric substrate with elongated strip conductors, The center frequency of each frequency band in the order of at least two or more required frequency bands from the higher frequency band to the lower frequency band in order from the one closer to the metal reflector is approximately 1/4 wavelength. Are arranged at a distance from each other and correspond to each of the required frequency bands.
A plurality of log-periodic dipoles excited from a wire, wherein the radio wave radiated from the log-periodic dipole is reflected by the metal reflector to radiate radio waves to the front side thereof. . 2. A log-periodic meander dipole section comprising at least one strip conductor of a plurality of dipole elements in at least one of said plurality of log-periodic dipole sections formed in a meander shape to form a meander dipole element. 2. The multi-frequency antenna device according to claim 1, wherein: 3. The two parallel lines between the adjacent log-periodic dipoles, between the log-periodic meander dipoles, or between the log-periodic dipoles and the log-periodic meander dipoles. 3. The multi-frequency antenna device according to claim 1, wherein an open stub having a line length of about 1/4 wavelength at a center frequency of a relatively high frequency band of a corresponding frequency band is connected in parallel. 4. The multi-frequency antenna device according to claim 1, wherein an anti-reflection means made of a matching load or a radio wave absorbing material is loaded at an end of the two parallel wires. 5. The method according to claim 1, wherein the two parallel wires are provided at necessary positions between the dipole elements and the meander dipole elements, which are different in impedance, and between the meander dipole elements.
A transformer formed by changing the line width of the line is provided to change the line width of the two parallel lines, and the characteristic impedance of the two parallel lines is matched with the impedance of the dipole element or the meander dipole element to be excited. The multi-frequency antenna device according to any one of claims 1 to 4, wherein: 6. The dielectric having the two parallel lines formed at required portions of the two parallel lines between the dipole element and the meander dipole element or between the meander dipole elements which have different impedances adjacent to each other. The portion of the body substrate is formed of dielectric materials having different dielectric constants to change the characteristic impedance of the two parallel wires, and the characteristic impedance of the two parallel wires is matched to the impedance of the dipole element or the meander dipole element to be excited. The multi-frequency antenna device according to any one of claims 1 to 4, wherein: 7. A multi-frequency antenna according to claim 1, wherein said antenna is an element antenna, and a plurality of said antennas are formed by using a common metal reflector for each metal reflector. A multi-frequency shared array antenna device, wherein the antennas are arranged so as to face each other, and radio waves radiated from each of the element antennas are reflected by the metal reflector and then combined to radiate polarized waves in a fixed direction. 8. A multi-frequency antenna device according to claim 1, wherein said antenna device is an element antenna, and a plurality of said antenna devices are orthogonally formed by forming respective metal reflectors with a common metal reflector. The antenna is arranged so as to face in the same direction, and excitation means is provided for making the phases of the radio waves radiated from the element antennas in the two directions orthogonal to each other in phase. The multi-frequency array antenna device is characterized in that it is combined and then radiates two polarized waves in directions orthogonal to each other. 9. The multi-frequency array antenna device according to claim 8, wherein said orthogonal means is used instead of said excitation means.
A multi-frequency array antenna device, comprising: exciting means for shifting the phases of radio waves radiated from element antennas in the respective directions by 90 degrees with respect to each other, and radiating circularly polarized waves. 10. The multi-frequency array antenna device according to claim 8, wherein a specific one of two or more required frequency bands from element antennas in each of the two orthogonal directions is used in place of said excitation means. Excitation means for shifting the phase of the radiated radio waves in the frequency band by 90 degrees to each other and making the phases of the radiated radio waves in the other frequency bands in-phase are provided. The polarized waves are circularly polarized in the specific frequency band and orthogonal to each other in the other frequency band. A multi-frequency array antenna device which emits two polarized waves in two directions.