JP4637939B2 - Stacked aperture array antenna - Google Patents

Description

The present invention relates to an antenna mainly used for communication using high frequencies such as microwaves and millimeter waves, and more particularly to a laminated aperture array antenna suitable for miniaturization and weight reduction.

In recent years, in the field of communication technology, research on mobile communication or inter-vehicle radar using high frequencies such as microwaves and millimeter waves has been actively promoted.
Usually, input / output of high-frequency signals between devices in these communications is ultimately performed by an antenna.
Various antennas used for such a high frequency have been studied, and typical examples include a waveguide slot antenna, a microstrip antenna, an aperture antenna, and the like.

 These high-frequency antennas are used by being connected to a high-frequency electric circuit. As a feed line for connecting these electric circuits and the antenna, for example, an open-face antenna or a waveguide slot antenna is used. For wave tubes and for microstrip antennas, triplate lines are mainly used.

Furthermore, recently, it is also desired to reduce the size of a communication system device including a high-frequency antenna by integrally manufacturing a radiating portion and a feeding portion of a high-frequency antenna in a dielectric substrate.
Microfilm of actual application No.46-088313

 In order to use the high-frequency antenna as described above for mobile communication, inter-vehicle radar, and the like, the antenna itself needs to be light, thin, and compact, easy to design, and highly efficient.

Among the high frequency antennas described above, the waveguide slot antenna has the advantage of being highly efficient and can be formed thin, but it is heavy because it is manufactured by processing a metal plate, and the cost is high. There is a point.
On the other hand, the microstrip antenna is manufactured by depositing a metal film on a dielectric sheet and molding it. Therefore, the microstrip antenna is light and thin, and can be easily manufactured, so that it is inexpensive. However, there is a problem that efficiency is low.

 On the other hand, an aperture antenna, for example, a horn antenna, has very good performance as an antenna characteristic, but because it is fabricated by three-dimensional processing using a metal member, it becomes large in size and is used for communication. There is a problem that it is difficult to mount on a terminal device and it is also difficult to reduce the weight.

Furthermore, even when any of the above high frequency antennas is used, the characteristics of the entire antenna system become important when the applied high frequency is in the millimeter wave region.
In other words, even if the individual characteristics of the high-frequency antenna, feed line, high-frequency circuit, etc. are very good, the whole system is configured by connecting all of them, so the characteristics and size of these connections The length and cost also affect the entire antenna system.
For example, if these connection portions are configured by waveguides, an antenna system can be configured without substantially impairing the performance of a high-frequency antenna, a power feeding circuit, a high-frequency circuit, or the like.
However, when connected by a waveguide, a three-dimensional structure is often obtained, and mechanical connection by screwing or the like is performed, leading to a problem of reduced reliability and increased cost.

In response to these problems, one of the present inventors has proposed a laminated aperture antenna in Japanese Patent Application No. 10-40813.
This proposal is characterized in that a conventional horn-type opening surface is used as a spatial resonator, and a structure that can be easily manufactured by a general lamination technique for a multilayer wiring board.

 However, in this laminated aperture antenna, the structure of the feeding part is that the dielectric waveguide is branched many times to increase the number of feeding waveguides, and the vicinity of the shorted part of each branched dielectric waveguide Power is supplied to the radiating unit from a single slot provided in the so-called parallel power supply. Although the design is easy, the area is increased due to the branching of the power supply unit, so it is difficult to reduce the size. It had the point which should be improved.

On the other hand, for the slot array antenna, a series feed structure has been devised in which a single waveguide feeds a plurality of slots.
This structure is intended to adjust the radiant energy by changing the dimensions of the slot, but since the slot directly becomes the radiation part of the antenna, the radiant energy radiated from each slot greatly changes due to the minute dimensional change of the slot. As a result, the energy radiated from each slot cannot be made sufficiently uniform, and as a result, the radiation pattern is disturbed.

In response to these problems, one of the present inventors has further proposed a multilayer aperture array antenna in Japanese Patent Application No. 11-184460.
This laminated aperture array antenna has an upper first main conductor layer and a lower main conductor layer sandwiching a first dielectric substrate, and a frequency less than half of the signal wavelength in the high-frequency signal transmission direction between the main conductor layers. Two rows of through conductor groups for side walls that are electrically connected at a repetition interval and a predetermined width, and an end face that electrically connects the main conductor layers in the width direction at a repetition interval of less than half the signal wavelength A second dielectric substrate formed by laminating a plurality of dielectric layers on the upper first main conductor layer of a dielectric waveguide having a through-conductor group for use, and the second dielectric substrate An upper second main conductor layer having a predetermined opening and formed in the second dielectric substrate around the opening, and the upper first main conductor layer and the Through conductors for a plurality of conductor walls electrically connecting the upper second main conductor layers And a plurality of through-conductors for conductor walls are formed to form an antenna conductor wall comprising a sub-conductor layer that electrically connects between the dielectric layers, and the upper first main conductor layer, the antenna conductor wall, and the upper second A plurality of spatial resonators constituted by a space surrounded by a main conductor layer are formed in the transmission direction, and slots for feeding are formed in the upper first main conductor layer corresponding to the spatial resonators, respectively. Also, in the above-described configuration, the slot has an emissivity from the i-th slot with respect to the first slot from the end surface through conductor group side. However, i is a natural number), and the dimensions are sequentially reduced so that i becomes a natural number.

 According to such a laminated aperture array antenna, power is supplied to a plurality of slots with a single dielectric waveguide line, and a spatial resonator is formed above the slot, resulting in a slight change in the dimensions of the slot. The fluctuation of the radiant energy is mitigated by a spatial resonator, and the energy radiated from each slot can be made uniform enough to obtain a highly efficient antenna.

However, in this method, if the slot dimensions are changed, the phase of the electromagnetic wave propagating through the dielectric waveguide line changes. Therefore, a design for correcting the phase change by changing the slot interval is necessary. There was a point to be improved that it is difficult to make the slot intervals equal and the design of the radiation pattern is not easy.
In other words, the density of radiant energy becomes non-uniform when the spacing between slots and spatial resonators is unequal, and design to adjust the energy radiated from each slot is necessary to make it uniform. there were.

 The present invention has been devised in view of the above circumstances, and its purpose is to enable downsizing, thinning, and high efficiency, and to make the radiant energy density uniform with a simple design, It is an object of the present invention to provide a stacked aperture array antenna that can be easily manufactured by a general stacking technique.

   As a result of repeated studies on the above problems, the present inventors have found that a second main conductor layer having an opening formed on the upper surface of a dielectric substrate on which a dielectric is laminated and an intermediate between the dielectric substrate and the second main conductor layer. A plurality of spatial resonators are formed by a first main conductor layer having a slot formed on a surface and a through conductor group electrically connecting the second main conductor layer and the first main conductor layer, For the two rows of side walls formed by forming a lower main conductor layer below the spatial resonator via a dielectric layer and electrically connecting the first main conductor layer and the lower main conductor layer. In a laminated aperture array antenna in which a dielectric waveguide line is formed by a conductor group, and a plurality of spatial resonators are serially fed by the dielectric waveguide line, the width of the dielectric waveguide line is reduced. By changing according to the feeding position, each slot is fixed with the interval between each slot fixed. Tsu can adjust the phase of the electromagnetic wave radiated from the bets, a simple design, can be a small and light with high efficiency, moreover, found that can be readily manufactured with conventional lamination techniques, has led to the present invention.

 That is, the multilayer aperture array antenna of the present invention has an upper first main conductor layer and a lower main conductor layer that sandwich the first dielectric substrate, and a signal wavelength that is divided into two in the direction of high-frequency signal transmission between the main conductor layers. Electrically connected at a repetition interval of less than 1 and with a predetermined width, and two rows of through conductors for side walls, and between the main conductor layers in the width direction with a repetition interval of less than a half of the signal wavelength A second dielectric substrate formed by laminating a plurality of dielectric layers on the upper first main conductor layer of the dielectric waveguide line comprising an end face through conductor group connected to the first dielectric layer; An upper second main conductor layer having a predetermined opening formed on the upper surface of the two dielectric substrate, and the upper first main layer formed in the second dielectric substrate around the opening and having a predetermined interval; A plurality of electrical connections between the body layer and the upper second main conductor layer. A body wall penetrating conductor and an antenna conductor wall comprising a sub-conductor layer electrically connecting the plurality of conductor wall penetrating conductors between the dielectric layers, and the upper first main conductor layer and the antenna conductor. A plurality of spatial resonators configured by a space surrounded by a wall and an upper second main conductor layer are formed in the transmission direction, and power is supplied to the upper first main conductor layer in correspondence with the spatial resonator. And the widths of the two through-wall side wall conductor groups are changed along the transmission direction so that the phases of the high-frequency signals radiated from the slots are the same. It is what.

 In the multilayer aperture array antenna of the present invention, in the above configuration, the widths of the two rows of through conductor groups for the side walls are made different between a portion sandwiching the slots and a portion between the slots. It is characterized by.

 Furthermore, the laminated aperture array antenna of the present invention is characterized in that, in each of the above configurations, the slots are formed at equal intervals in the transmission direction.

 According to the multilayer aperture array antenna of the present invention, a plurality of spatial resonators are dielectrically arranged on the same plane on a part of a dielectric substrate formed by laminating dielectric layers on a multilayer dielectric waveguide line. A plurality of spatial waveguides are formed in the transmission direction, and the plurality of spatial resonators are serially fed by a single dielectric waveguide without branching from each slot. The width of the body waveguide line is changed along the transmission direction of the high frequency signal so that the phase of the high frequency signal radiated from each slot is the same. By adjusting the width, the phase of the electromagnetic wave radiated from each slot can be freely adjusted while the position of each slot is fixed, thereby making it possible to easily design a uniform radiation pattern.

In other words, if electromagnetic waves with the same phase are radiated from each slot, the width of the dielectric waveguide line is adjusted in the direction in which the phase change due to the size of each slot is corrected, that is, in the direction in which each electromagnetic wave has the same phase. Adjust narrow or wide.
Also, if electromagnetic waves are radiated at a certain angle, it is changed to an antenna element by adjusting the width of the dielectric waveguide line so that the phase of the electromagnetic waves radiated from each slot is slightly different. It is possible to design such that a desired radiation pattern can be obtained without adding.

 As described above, according to the multilayer aperture array antenna of the present invention, in a structure in which a plurality of spatial resonators are serially fed via a slot by a dielectric waveguide line for feeding, the dielectric waveguide line By changing the width of the antenna according to the feeding position along the transmission direction, a stacked aperture array antenna can be obtained in which the phase of the electromagnetic wave radiated from each slot can be adjusted without changing the design of the slot and the spatial resonator. .

 Further, according to the multilayer aperture array antenna of the present invention, in the above configuration, the width of the dielectric waveguide line for feeding is made different between the portion sandwiching each slot and the portion between each slot. In this case, the laminated aperture array antenna can be obtained in which the phase of the electromagnetic wave radiated from each slot can be adjusted while changing the guide wavelength and fixing the design of the slot and the spatial resonator.

 Furthermore, according to the multilayer aperture array antenna of the present invention, in the above-described configurations, when the slots are formed at equal intervals in the transmission direction of the dielectric waveguide line, the intervals between the slots and the spatial resonators are equal. A multilayered aperture array antenna can be obtained in which uniform electromagnetic wave radiation can be performed while maintaining an interval, and the phase of the electromagnetic wave radiated from each slot can be unified and uniform.

 According to the multilayer aperture array antenna of the present invention, a plurality of spatial resonators are formed on a same plane on a part of a dielectric substrate formed by laminating dielectric layers, and the plurality of spatial resonances are formed. Since the series feeding is performed with a single laminated dielectric waveguide line having no branch with respect to the device, the feeding structure with the laminated dielectric waveguide line can be simplified.

 In other words, according to the feeding structure with a single laminated dielectric waveguide line without branching, a highly efficient multilayered aperture array antenna with little loss of energy because the line length is short and there is no branching. can do.

 Furthermore, the amount of radiant energy supplied from each slot to the spatial resonator can be adjusted by adjusting the slot length according to the positional relationship with the feeder line. However, the energy is radiated through the spatial resonator once. Therefore, the change in the amount of radiation with respect to the change in the size of the slot becomes insensitive, the amount of radiation emitted from each spatial resonator can be sufficiently uniformed, and as a result, a uniform radiation pattern can be obtained and at the same time good Antenna characteristics can be obtained.

 In addition, since the antenna and the feed line can be integrally formed on the dielectric substrate, and the feed line pattern for a plurality of spatial resonators uses a laminated dielectric waveguide line and is simple, Not only the thickness of the dielectric substrate but also the dimensions in the plane direction can be reduced, and the entire system can be reduced in size and weight.

 According to the multilayer aperture array antenna of the present invention, a through-hole conductor such as a via-hole conductor formed in a dielectric substrate formed by laminating a plurality of dielectric layers based on a lamination technique for a multilayer wiring substrate, and the dielectric Since the antenna conductor wall is formed by a combination with a conductor layer disposed between body layers, an aperture antenna can be easily and inexpensively manufactured.

In addition, a space surrounded by the antenna conductor wall and the corresponding opening of the upper second main conductor layer and the lower first main conductor layer is defined as a one-sided short-circuited / one-sided open 1/4 wavelength resonant space (spatial resonator). Since electromagnetic waves are radiated from the opening surface, the radiation frequency can be controlled by the size of the opening surface and the thickness of the spatial resonator, that is, the thickness of the dielectric substrate.
This gives a degree of freedom in design. For example, if the size of the aperture is increased, the thickness of the space where the aperture antenna is formed can be reduced, so the number of stacked dielectric layers can be reduced. As a result, it can be manufactured at a lower cost.

In addition, since the laminated aperture array antenna of the present invention can be formed by a conventional lamination technique, it can be integrally formed in a normal multilayer wiring board, and at the same time, a feeding line to the antenna is formed at the same time. it can.
In addition, since it can be manufactured through a series of processes using conventional multilayer technology, a highly reliable and low-cost laminated aperture array antenna can be manufactured.

Normally, when a slot is provided in a dielectric waveguide line, the phase of the in-tube wave in the waveguide line changes as shown in FIG. 3 depending on the size of the slot.
FIG. 3 is a diagram showing the relationship between the dimension of the slot formed in the dielectric waveguide line and the phase of the wave in the tube relative to the dimension. The horizontal axis represents the slot length (unit: mm), and the vertical axis represents the inside of the tube. It represents the wave phase shift (unit: °), and the characteristic curve shows the change of the phase shift with respect to the slot length.
As described above, when the slot is formed in the dielectric waveguide line, the phase of the in-tube wave is shifted, so that it is necessary to align the phase of the electromagnetic wave radiated from each slot. In the dielectric waveguide line, the influence of the phase change due to the slot is canceled by slightly changing the slot interval.
For this reason, in the conventional laminated aperture array antenna, the intervals between the slots cannot be made equal, and the design is difficult.

 Here, there is the following relationship between the width A of the dielectric waveguide line for feeding and the wavelength λp in the tube, where the wavelength of the free space electromagnetic wave is λ.

λp = λ / {1- (λ / 2A) ² } ^1/2
In this relationship, the guide wavelength λp can be changed by changing the width A of the dielectric waveguide.

 In the multilayer aperture array antenna of the present invention, the phase of the electromagnetic wave radiated from each slot can be freely adjusted based on this, and the design of the radiation pattern can be easily performed as desired. Can be done.

 In the laminated aperture array antenna of the present invention, the position of each slot is similarly fixed by making the width of the dielectric waveguide line different between the part holding the slot and the part between the slots. Since the phase of the electromagnetic wave radiated from each slot can be freely adjusted, the radiation pattern can be easily designed as desired.

 Furthermore, in the laminated aperture array antenna of the present invention, slots are formed at equal intervals in the transmission direction with respect to the dielectric waveguide line so that the slot interval and the space resonator are equally spaced. The density of the radiant energy of the electromagnetic wave can be made uniform, and the design becomes easy.

 Hereinafter, the laminated aperture array antenna of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partially transparent perspective view showing an example of an embodiment of the laminated aperture array antenna of the present invention.
In FIG. 1, 1 is a dielectric substrate, 2 is an upper first main conductor layer, 3 is a lower first main conductor layer, 4 is a through conductor group for side walls, 5 is a through conductor group for end faces, and 6 is a dielectric waveguide. 7 is a dielectric layer, 8 is a second dielectric substrate formed by laminating the dielectric layer 7, 9 is an upper second main conductor layer, 10 is an opening, and 11 is a through conductor group for conductor walls. , 12 are sub-conductor layers, 13 is a space (spatial resonator), and 14 is a slot.
FIG. 1 shows a perspective view of a part of the dielectric layer 7 of the first dielectric substrate 1 and the second dielectric substrate 8.

According to the example shown in FIG. 1, in the laminated aperture array antenna of the present invention, a plurality of spatial resonators 13 are formed on a second dielectric substrate 8 formed by laminating a plurality of dielectric layers 7 having a predetermined thickness. The substrate is used.
An upper second main conductor layer 9 is formed on the upper surface of the second dielectric substrate 8 and an upper first main conductor layer 2 is formed on the lower surface.
The upper first main conductor layer 2 is also formed by being deposited on the upper surface of the first dielectric substrate 1 on which the second dielectric substrate 8 is formed. A lower main conductor layer 3 is formed on the lower surface of the substrate.

 As described above, the plurality of spatial resonators 13 are formed between the upper second main conductor layer 9 and the upper first main conductor layer 2, and dielectric waveguides that feed power to the respective spatial resonators 13. Since the line 6 is formed between the upper first main conductor layer 2 and the lower main conductor layer 3, the antenna 6 is formed inside the dielectric substrate composed of the first dielectric substrate 1 and the second dielectric substrate 8. It has a structure in which the radiating portion and the feeding portion are provided integrally.

The spatial resonator 13 formed between the upper first main conductor layer 2 and the upper second main conductor layer 9 is configured as follows.
That is, the upper second main conductor layer 9 is formed with a plurality of rectangular openings 10 having, for example, an opening size of a × b, which serve as a radiating portion of the antenna.
Then, the upper first main conductor layer 2 and the upper second main conductor layer 9 are electrically connected to the second dielectric substrate 8 around the opening 10 of the upper second main conductor layer 9. A plurality of via-hole conductor groups 11 such as via-hole conductors and through-hole conductors are formed in the laminating direction of the dielectric layer 7 with a predetermined interval.
The conductor wall through conductor group 11 is formed between the dielectric layer 7 and the upper first main conductor layer 2 and the upper second main conductor layer 9 in parallel with the strip-shaped sub conductor layer 12 having an opening size of a × b. Thus, the antenna conductor walls parallel to the zx plane and the yz plane shown in the figure are formed.

The upper first main conductor layer 2 electrically connected to the antenna conductor wall is also the main conductor layer on the upper side of the dielectric waveguide 6 and is at least dimensioned at a position facing the opening 10. Is formed so as to cover a region larger than the a × b opening 10.
As a result, the antenna conductor wall constituted by the upper second main conductor layer 9 having the opening 10, the plurality of conductor wall through conductor groups 11, and the one or more sub conductor layers 12, and the upper first main conductor layer 2 are formed. A spatial resonator 13 is formed which is a space of a rectangular parallelepiped shape having a size of a × b × c and is surrounded by a radiating portion of the laminated aperture array antenna.

 Since this antenna conductor wall must be formed so that electromagnetic waves do not leak from this conductor wall, the distance between the sub-conductor layers 12 and the distance between the conductor wall through conductor groups 11 are at least the signal wavelength. Are arranged with an interval of less than ½, preferably with an interval of ¼ or less of the signal wavelength.

Since this antenna applies the principle of a quarter-wave resonator of single-sided short-circuiting and single-sided opening, the characteristics of electromagnetic waves radiated from the aperture surface differ depending on the resonance mode.
Therefore, various applications can be considered depending on the purpose.
For example, if the rectangular parallelepiped TE111 mode is used, electromagnetic waves are not emitted in the antenna front direction but in a certain angle ± θ direction. In general, it is desirable to use the hexahedral TE101 mode.
At this time, the frequency f [GHz] of the electromagnetic wave radiated from the antenna can be calculated by the following equation.
f = 150 × {(1 / a) ² + (1 / 2c) ² } ^1/2 × ε _r ^−1/2
However, (epsilon) _r is a dielectric constant and the unit of a and c is mm.

 Here, the length b of the opening 10 may be equal to or less than the width a, but if it is too small, the loss of energy due to the conductor increases, so care must be taken.

In the above example, the example in which the spatial resonator 13 has a rectangular parallelepiped shape is shown, but the same applies when the resonant space is cylindrical.
However, in this case, it is desirable to use the cylinder TE111 mode.
At this time, the frequency f [GHz] of the electromagnetic wave radiated from the antenna can be calculated by the following equation.
f = 150 × {(1 / 2c) ² + (χ11 ′ / πa) ² } ^1/2 × ε _r ^−1/2
Here, χ11 ′ is the first root of the derivative of the first-order Bessel function, and the units of a and c are mm.

 As shown in FIG. 1, when the opening 10 has a rectangular shape and the spatial resonator 13 has a rectangular parallelepiped shape, the polarization plane of the radiated electric field can be easily fixed, and an excellent linearly polarized antenna element It becomes.

When the opening 10 is circular and the spatial resonator 13 is cylindrical, the plane of polarization of the radiated electric field is determined by the slot 14 that feeds the spatial resonator 13.
Therefore, by adjusting the phase using two slots, a circularly polarized antenna element having a good axial ratio can be obtained.

 The feed structure to the plurality of spatial resonators 13 in the multilayer aperture array antenna of the present invention is configured between the upper first main conductor layer 2 and the lower main conductor layer 3 as follows. Yes.

According to FIG. 1, an upper first main conductor layer 2 is formed on the upper surface of the first dielectric substrate 1, and a lower main conductor layer 3 is formed on the lower surface of the first dielectric substrate 1, and the upper first main conductor layer is formed. 2 constitutes the lower surface of the spatial resonator 13.
In addition, a plurality of through conductors such as through-hole conductors and via-hole conductors that electrically connect them are provided between the upper first main conductor layer 2 and the lower main conductor layer 3, and two rows of through conductors for side walls Group 4 is formed.
Two rows of through-hole conductor groups 4 for sidewalls formed with a predetermined interval A in the width direction of the dielectric waveguide 6 are less than a half of the signal wavelength in the signal transmission direction (preferably a quarter). And a side wall of the dielectric waveguide 6 is formed.

Here, there is no particular limitation on the distance B between the upper first main conductor layer 2 and the lower main conductor layer 3, but when used in a single mode, it is half (1/2) of the distance A. It is good to make it about twice.
In the example of FIG. 1, the portions corresponding to the E and H surfaces of the dielectric waveguide are respectively formed as an upper first main conductor layer 2, a lower main conductor layer 3, and a side wall through conductor group 4. The sub conductor layer 15 is formed.

Further, the through-conductor group 4 for the side wall forms an electrical wall by setting the pitch C of each through-conductor of the through-conductor group 4 for the side wall to be less than half the signal wavelength.
Here, if the gap between the through conductor of the side wall through conductor group 4 and the sub conductor layer 15 or the gap between the two sub conductor layers 15 adjacent vertically is larger than ½ of the signal wavelength, the gap is Since the electromagnetic wave leaks from the slot due to acting as a slot, even if the electromagnetic wave is fed to the dielectric waveguide 6, the electromagnetic wave does not propagate along the pseudo waveguide made here.
However, if the gap is made smaller than ½ of the signal wavelength, the leakage of the electromagnetic wave is settled and propagates along this pseudo waveguide.
as a result,
According to the configuration shown in FIG. 1, a pair of upper first main conductor layer 2 and lower main conductor layer 3 disposed at a distance C, and two rows of through conductor groups for side walls 4 disposed at a distance A and a sub-conductor layer 15. A region having a cross-sectional area of B × A surrounded by is a dielectric waveguide 6 that feeds power to each spatial resonator 13.

The plurality of spatial resonators 13 are fed by a slot 14 formed in the upper first main conductor layer 2 of one dielectric waveguide 6.
One end of the dielectric waveguide 6 is less than half of the signal wavelength in the width direction of the dielectric waveguide 6 between the upper first main conductor layer 2 and the lower main conductor layer 3. The end surface through conductor groups 5 that are electrically connected at repeated intervals and the upper side first main conductor layer 2 and the lower main conductor layer 3 are formed in parallel between the two rows of through conductor groups 4 for the side walls. It is short-circuited by the sub-conductor layer 15 to be connected to become a short-circuited end, and the other is an open end.
By feeding power from the open end, electromagnetic waves propagate through the dielectric waveguide 6, and the upper first main conductor layer 2 is provided with slots 14 at positions corresponding to the respective spatial resonators 13. For this reason, every time the electromagnetic wave reaches the slot 14, a part of the electromagnetic energy is sequentially fed from the slot 14 to the spatial resonator 13, and the rest further propagates through the dielectric waveguide line 6.
For this reason, the electromagnetic energy propagating through the waveguide 6 decreases as it approaches the short-circuit end from the open end.
When n spatial resonators 13 and slots 14 are numbered sequentially as i = 1, 2, 3,..., N in order from the short-circuited end, the dimensions of the spatial resonators 13 are the same. The energy radiated from each slot 14 to each spatial resonator 13 is adjusted by adjusting the size of each slot 14 so that the emissivity Ri radiated from the i-th slot 14 is given by the following relational expression. Can be made uniform.
Ri = 1 / i That is, the emissivity of the first slot 14 closest to the short-circuit end is 1/2, the emissivity of the second slot 14 is 1/2, and the emissivity of the third slot 14 is 1/3 or less. The amount of radiation from each slot 14 can be made uniform by adjusting the size of each slot 14 so that it becomes 1/4, 1/5.

As described above, the radiation amount from each spatial resonator 13 of the laminated aperture array antenna can be adjusted by changing the size of the slot 14.
That is, by changing the dimension of the slot 14 according to the position of the spatial resonator 13 from the short-circuited end of the dielectric waveguide 6 to be fed, for example, the slot length, from each slot 14 to each spatial resonator 13. It is possible to make the energy of the emitted electromagnetic wave uniform.

FIG. 4 is a diagram showing the relationship between the slot length of the slot 14 and the emissivity of electromagnetic energy radiated from the slot 14 to the spatial resonator 13.
In FIG. 4, the horizontal axis represents the slot length l (unit: mm) of the slot 14, the vertical axis represents the emissivity from the slot 14, and the points indicated by black triangles and the characteristic curve connecting them represent the slot length l. Shows the change in emissivity with respect to.
In addition, the measurement at this time evaluated the reflection and insertion loss in 77 GHz using the network analyzer, and calculated radiation | emission etc. using the data.

 Each slot 14 of the multilayer aperture array antenna according to the present invention uses the relationship shown in FIG. 4 as described above to determine the predetermined predetermined frequency according to the position of each spatial resonator 13 on the dielectric waveguide 6. The dimensions, eg length, are adjusted accordingly.

The dielectric waveguide line 6 that feeds each spatial resonator 13 has a waveguide size of a normal waveguide when the relative dielectric constant of the first dielectric substrate 1 is ε _r. of 1 / √ε _r it is possible to size the, is possible to reduce the size of the dielectric waveguide line 6 larger the relative dielectric constant epsilon _r of the material constituting the first dielectric substrate 1 As a result, the stacked aperture array antenna can also be reduced in size.

The through conductors constituting the side wall through conductor group 4 are arranged in the transmission direction at a repetitive interval C of less than one half of the signal wavelength.
This interval C is preferably a constant repetition interval in order to realize good transmission characteristics, but may be changed or combined with several values as long as the interval is less than half the signal wavelength. May be.

In the multilayer aperture array antenna of the present invention, the width A between the two rows of through-wall conductor groups 4 and 4 in the dielectric waveguide 6 is set to the phase of the high-frequency signal radiated from each slot 14. Is characterized by being varied narrower or wider along the transmission direction so as to be the same.
When the width A between the two through-wall side wall conductor groups 4 and 4 is changed in this way, the change is
A = (λ / 2) × {λp ² / (λp ² −λ ² )} ^1/2
In the equation, the relationship of λ: free space wavelength λp: guide wavelength is used, the guide wavelength λp is determined so as to obtain the target phase difference, and the width A is obtained.

 As a result, by changing the width A of the dielectric waveguide 6, the guide wavelength λp is changed, and is radiated from each slot 14 by correcting the phase shift between the slots 14 shown in FIG. 3. The phase of the high-frequency signal can be made the same, and the antenna having a uniform radiation pattern can be easily designed by sufficiently equalizing the radiation amount of the electromagnetic wave.

Next, FIG. 2 is a partially transparent perspective view showing another example of the embodiment of the multilayer aperture array antenna of the present invention.
In FIG. 2, the same parts as those in FIG.

In the example shown in FIG. 2, the width A ′ between the two through-wall side wall conductor groups 4, 4 in the dielectric waveguide 6 is determined between the portion sandwiching each slot 14 and the portion between each slot 14. It is characterized by being different.
Thus, when the width A ′ between the two through-wall side wall conductor groups 4 and 4 is changed, the change is as follows: λ is the free space wavelength and λp is the in-tube wavelength.
A ′ = (λ / 2) × {λp ² / (λp ² −λ ² )} ^1/2
The width A ′ may be determined so as to correct the phase shift shown in FIG.

 Thus, the phase of the high-frequency signal radiated from each slot 14 is changed by changing the guide wavelength λp in the dielectric waveguide 6 between adjacent slots 14 so as to cancel the phase shift between the slots 14. Therefore, it is possible to easily design an antenna having a uniform radiation pattern by sufficiently equalizing the radiation amount of electromagnetic waves in a state where the design of the slot 14 and the spatial resonator 13 is fixed.

 According to the multilayer aperture array antenna of the present invention, in the example shown in FIGS. 1 and 2, the slots 14 are formed at equal intervals in the transmission direction of the dielectric waveguide 6 so as to be adjacent to each other. Since the phase of the matching antenna element is adjusted at a constant interval by changing the guide wavelength λp, the phase of the electromagnetic wave radiated from each slot 14 can be made almost uniform and uniform. .

 The first dielectric substrate 1 constituting such a laminated aperture array antenna is not particularly limited as long as it has a characteristic that functions as a dielectric and does not hinder the transmission of high-frequency signals. The first dielectric substrate 1 is preferably made of ceramics from the viewpoint of accuracy in forming the transmission line and ease of manufacture.

As such ceramics, ceramics having various relative dielectric constants have been known so far. In order to transmit a high-frequency signal through the dielectric waveguide line 6 according to the laminated aperture array antenna of the present invention, A paraelectric material is desirable.
This is because ferroelectric ceramics generally have a large dielectric loss and a large transmission loss in the high frequency region.
Accordingly, the relative dielectric constant ε _r of the first dielectric substrate 1 is suitably about 4 to 100.

In general, the thickness of one layer of a wiring layer formed in a multilayer wiring board, a semiconductor element storage package, or an inter-vehicle radar is at most about 1 mm. Therefore, a material having a relative dielectric constant ε _r of 100 is used and the side wall is When used so as to have an electromagnetic field distribution in which the H-plane, that is, the magnetic field wraps parallel to the surface of the side wall, the minimum frequency that can be used is calculated as 15 GHz and can be used even in the microwave band region.

On the other hand, a dielectric made of a resin generally used as the first dielectric substrate 1 has a relative dielectric constant ε _r of about 2, so that when the thickness of the wiring layer is 1 mm, it is not more than about 100 GHz. It will not be possible.

In addition, many of such paraelectric ceramics have very small dielectric loss tangents such as alumina and silica, but not all paraelectric ceramics are available.
In the case of the dielectric waveguide 6, there is almost no loss due to the conductor, and most of the loss during signal transmission is due to the dielectric.
The loss α (dB / m) due to the dielectric is expressed as follows.
α = 27.3 × tan δ / [λ / {1- (λ / λc) ² } ^1/2 ]
Where tan δ is the dielectric loss tangent of the dielectric λ is the wavelength in the dielectric λ c is the cut-off wavelength standardized rectangular waveguide (WRJ series) shape, {1- (λ / λ c) in the above equation ² } ^1/2 is about 0.75.

 Therefore, in order to reduce the practical transmission loss to −100 dB / m or less, it is necessary to select a dielectric so that the following relationship is satisfied.

f × ε _r ^1/2 × tan δ ≦ 0.8
In the formula, f is the frequency (GHz) of the high-frequency signal to be used.

The first dielectric substrate 1 / dielectric layer 7 and the second dielectric substrate 8 in the above embodiments can be formed into sheets with appropriate thicknesses, and a conductive layer such as a metallized layer can be deposited. Thus, any dielectric material can be used as long as it can form through conductors such as via-hole conductors and can be closely stacked.
For example, various materials such as ceramics, glass ceramics, and resins may be used, and a mixture of resin and ceramic powder may be used.
Further, in order to reduce the transmission loss of the high-frequency signal as much as possible, the dielectric tangent of the dielectric material is preferably small, and is preferably 0.001 or less at the frequency used.

 Furthermore, the upper first main conductor layer 2, the lower main conductor layer 3, the upper second main conductor layer 9, the sub-layer are deposited on the first dielectric substrate 1, the dielectric layer 7 and the second dielectric substrate 8. The conductor layer such as the metallized layer that becomes the conductor layer 12 and the sub-conductor layer 15 is preferably composed of a low-resistance conductor with low transmission loss of high-frequency signals, and preferably at least one of gold, silver, and copper It is good to have as a main component.

 Next, the manufacturing method of the laminated aperture array antenna of the present invention will be described.

As the first dielectric substrate 1, the dielectric layer 7, and the second dielectric substrate 8, ceramics such as alumina ceramics, glass ceramics, and aluminum nitride ceramics are used.
In this case, an appropriate organic solvent / solvent is added to and mixed with these ceramic raw material powders to form a slurry, and by adopting a conventionally known doctor blade method, calendar roll method, or the like, a sheet shape is obtained. Obtain multiple ceramic green sheets.
Then, for example, if the dielectric is made of alumina ceramic, add a suitable oxide, organic solvent or solvent such as alumina, silica, magnesia, etc. to a metal powder such as tungsten, molybdenum, manganese, etc. The resulting product is printed on this ceramic green sheet in a pattern that will be the main conductor layers 2, 3, 9 and the sub conductor layers 12, 15 by thick film printing.

In addition, for example, a ceramic green sheet is punched by punching or the like in a portion that becomes a through conductor of each through conductor group 4, 5, and 11, and a metal such as tungsten, molybdenum, manganese, or the like An appropriate oxide such as alumina, silica, and magnesia, an organic solvent, a solvent, and the like are added to the powder and mixed to form a paste.
Each ceramic green sheet is appropriately punched and laminated, and the ceramic ceramic sheet is 1500-1700 ° C for alumina ceramics, 850-1000 ° C for glass ceramics, and 1600-1900 ° C for aluminum nitride ceramics. It is manufactured by firing at a temperature of

The metal powder used for forming the main conductor layers 2, 3, 9 and the sub conductor layers 12, 15 and the through conductors of the through conductor groups 4, 5, 11 is used when the dielectric is glass ceramics. In the case of copper / gold / silver and aluminum nitride ceramics, tungsten / molybdenum is suitable.
The thicknesses of the main conductor layers 2, 3, 9 and the sub conductor layers 12, 15 are usually about 5 to 50 μm.

Further, the cross-sectional shape of the through conductors of each through conductor group 4, 5, 11 may be a polygon such as a rectangle or a rhombus in addition to a circle that is easy to manufacture.
These through conductors are formed, for example, by embedding a metal paste similar to that of the main conductor layers 12 and 13 into a through hole produced by punching a ceramic green sheet, and then firing the same simultaneously with the ceramic green sheet.
In addition, as for the magnitude | size of these penetration conductors, the diameter of 50-300 micrometers is suitable.

A multilayer aperture array antenna of the present invention having the configuration shown in FIG. 1 was produced.
A plurality of spatial resonators 13 are formed in the transmission direction on the laminated dielectric waveguide line 6, and the dielectric waveguide line 6 is used as a feed line for each spatial resonator 13, The first main conductor layer 2 is provided with a power feeding slot 14 corresponding to each spatial resonator 13.

 Each spatial resonator 13 was a rectangular parallelepiped with dimensions a = 3.4 mm · b = 1.3 mm · c = 0.5 mm, and the center frequency was 77 GHz.

 Dielectric waveguide line 6 gradually changes the width A between the two through-wall side wall conductor groups 4 and 4 from 1.5 mm to 1.1 mm along the transmission direction to form slots 14 at equal intervals. In this state, the phase of the electromagnetic wave radiated from each slot 14 was made the same.

The height B of the dielectric waveguide 6 is constant at 0.6 mm.
Further, low-temperature sintered glass ceramics having a relative dielectric constant ε _r of 5 and a dielectric loss tan δ of 0.0008 was used for the dielectric material of the dielectric layer, and a copper metallized layer was used for each conductor layer.

The width of each slot 14 (the length in the transmission direction of the dielectric waveguide 6) is unified to 0.15 mm, and the length (the length in the width direction of the dielectric waveguide 6) is 0.9 mm to The emissivity was changed between 0.4 mm so as to satisfy the predetermined relationship according to the feeding position.
The first slot 14 was provided at a position of 1.1 mm in the transmission direction from the formation position of the end face through conductor group 5 which is a short-circuited end of the dielectric waveguide 6.

Regarding the laminated aperture array antenna of the present invention formed as described above, 16 spatial resonators are formed in the transmission direction on four dielectric waveguide lines, respectively, and an array antenna of 4 × 16 elements. Was made.
The four dielectric waveguide lines were fed using two branches.
For comparison, 16 spatial resonators in the transmission direction are provided on four dielectric waveguide lines using a multilayer aperture antenna with a constant width of the conventional dielectric waveguide line. An array antenna of 4 × 16 elements was also formed.

As a result of evaluating the characteristics of the two array antennas by the near-field measurement method, the gain of the conventional multilayer aperture array antenna was 22 dBi, whereas the multilayer aperture array antenna of the present invention was excellent at 23 dBi. It was a thing.
In the multilayer aperture array antenna of the present invention, the radiation pattern was good because the electric field intensity distribution on the antenna element surface was uniform.

 Note that the arrayed aperture array antenna of the present invention shown in FIG. 2 was also fabricated and evaluated in the same manner, and it was confirmed that it had the same good antenna characteristics.

 Further, in the same manner as described above, the same evaluation was performed for the case where the opening 10 had a circular shape with a diameter of 1.7 mm, and the spatial resonator 13 had a cylindrical shape with a diameter of 1.7 mmφ × c = 0.45 mm. It was confirmed that the antenna characteristics were as good as those described above.

In addition, this invention is not limited to the example of the above embodiment, A various change and improvement can be added in the range which does not deviate from the summary of this invention.
For example, the opening 10 may be triangular, and the spatial resonator may be triangular.

  As described above in detail, according to the laminated aperture array antenna of the present invention, one-sided short-circuited / single-sided open quarter is formed on the upper main conductor layer of the laminated dielectric waveguide line whose one end is short-circuited. A plurality of spatial resonators constituting the wavelength resonant space are formed in the transmission direction, and slots for feeding are formed in the upper main conductor layer of the dielectric waveguide line so as to correspond to the spatial resonators respectively. The width of the body waveguide line is changed along the transmission direction so that the phase of the high-frequency signal radiated from each slot is the same, or is different between the part holding each slot and each slot. Therefore, it is possible to obtain a highly efficient stacked aperture array antenna and to control the phase of the electromagnetic wave of the high-frequency signal radiated from each antenna element as desired with the antenna element design fixed. High frequency applications that can be made uniform enough, can be reduced in size and thickness, have good antenna characteristics, and can be easily and inexpensively manufactured with conventional multilayer technology with a simple design Antennas can be provided.

 Further, when the slots are formed at equal intervals in the transmission direction of the dielectric waveguide line, the phase of the radiated electromagnetic wave can be almost completely unified and further uniformized.

 Further, according to the multilayer aperture array antenna of the present invention, the radiation frequency can be controlled by the size of the aperture surface and the thickness of the spatial resonator, that is, the thickness of the dielectric substrate. It can also be made smaller and thinner, easily and inexpensively, and can be manufactured in a series of processes using conventional multilayer technology, so it can be formed integrally in a normal multilayer wiring board. In addition, a highly reliable stacked aperture array antenna can be manufactured at low cost.

It is a partial see-through perspective view showing an example of an embodiment of a laminated aperture array antenna of the present invention. FIG. 6 is a partial perspective view showing another example of the embodiment of the laminated aperture array antenna of the present invention. It is a diagram which shows the relationship between the dimension of the slot formed in the dielectric waveguide line, and the phase of an in-tube wave with respect to it. It is a diagram which shows the relationship between the slot length and the emissivity in the laminated aperture array antenna of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ...... 1st dielectric substrate 2 ... Upper 1st main conductor layer 3 ... Lower main conductor layer 4 ... Side wall through conductor group 5 ... End face through conductor group 6 ... Dielectric waveguide 7 ... Dielectric layer 8 ... Second dielectric substrate 9 ... Upper second main conductor layer 10 ... Opening 11 ... .... Conductor wall through conductor group 12 ... Sub conductor layer 13 ... Spatial resonator 14 ... Slot A, A '... Width of two rows of through conductor groups

Claims (2)

An upper first main conductor layer and a lower main conductor layer sandwiching the first dielectric substrate, and the main conductor layer are electrically connected at a repetition interval and a predetermined width of less than a half of the signal wavelength in the high-frequency signal transmission direction. Two side wall through conductor groups connected to each other, and an end face through conductor group that electrically connects the main conductor layers in the width direction at a repetition interval of less than one half of the signal wavelength. On the upper first main conductor layer of the dielectric waveguide line comprising:
A second dielectric substrate formed by laminating a plurality of dielectric layers; an upper second main conductor layer deposited on the upper surface of the second dielectric substrate and having a predetermined opening; A plurality of through conductors for a conductor wall formed in the second dielectric substrate and electrically connecting the upper first main conductor layer and the upper second main conductor layer with a predetermined interval, and the through holes for the plurality of conductor walls A space surrounded by the upper first main conductor layer, the antenna conductor wall, and the upper second main conductor layer. The antenna conductor wall includes a sub conductor layer that electrically connects a conductor between the dielectric layers. Forming a plurality of spatial resonators configured in the transmission direction, and feeding the plurality of spatial resonators in series with the dielectric waveguide line,
Slots for power feeding are formed in the upper first main conductor layer so as to correspond to the spatial resonators, respectively, and the widths of the through-hole conductor groups for the two rows are set to the width of the high-frequency signal radiated from the slots. Change along the transmission direction so that the phase is the same,
A stacked aperture array antenna, wherein the slots are formed at equal intervals in the transmission direction. 2. The laminated aperture array antenna according to claim 1, wherein widths of the two rows of through-hole conductor groups for the side walls are made different between a portion sandwiching the slots and a portion between the slots.

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