JP2004356880A - Circular polarization array antenna and board with antenna using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circular polarization array antenna and a board with an antenna which provides a good axial ratio characteristic on the whole of the array antenna, even if there is some mutual coupling between radiation elements. <P>SOLUTION: The circular polarization array antenna has a plurality of radiation elements formed in array on a specified board surface. A part of the radiation elements or all of them have each an elliptic polarization characteristic. The elliptic polarization characteristics of the radiation elements are adjusted to cancel the deviation of the axial ratio due to the interaction between the radiation elements, thereby reducing the axial ratio of the entire array antenna below 3 dB. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a circularly polarized wave array antenna suitable for wireless communication using a high-frequency signal such as a millimeter wave band, and a substrate with the antenna provided with the same.
[0002]
[Prior art]
Examples of radiating elements that emit radio waves of high-frequency signals such as millimeter waves include slot antennas and patch antennas. These are widely used because of their simple structure, and those using a microstrip line, a waveguide line, or the like as a feed line have been proposed.
[0003]
In addition, there are two types of feeding methods for array antennas, in which a plurality of radiating elements are arranged: parallel feeding and series feeding.However, transmission loss of the feed line becomes a problem at higher frequencies. Has been adopted. In the case of the parallel feeding method, the slots and patches of the elements of the slot antenna and patch antenna are set to the resonance size so that the maximum radiation can be obtained.In the case of the series feeding method, the electromagnetic wave gradually increases from the feeding end side. In order to radiate the radiation, the radiation amount is adjusted by setting the slots and patches to be smaller or larger than the resonance size.
[0004]
Further, as the polarization technique, there are linear polarization and circular polarization. In the case of a wireless communication device, a circular polarization antenna is frequently used in order to suppress the influence of a reflected wave from a wall or the like. This means that in the case of linear polarization, the reflected wave is directly picked up, whereas in the case of circular polarization, for example, when radiating right-handed circularly polarized light, the reflected wave becomes left-handed circularly polarized light. This is because primary reflected waves from walls and the like are not picked up.
[0005]
There are the following techniques for emitting circularly polarized waves. The slot antenna is realized by, for example, forming a slot in a conductor wall of a waveguide type feeder line in a direction parallel to and perpendicular to a traveling direction of an electromagnetic wave. The patch antenna is realized by a rectangular or elliptical patch.
[0006]
Recently, it has been studied to manufacture these antennas on a ceramic substrate. Conventionally, in order to obtain good antenna characteristics, a resin substrate having a low relative dielectric constant has been used, but a package in which an MMIC or the like is sealed cannot be directly mounted due to a large thermal expansion coefficient of the substrate. , Which led to increased costs.
[0007]
On the other hand, by forming the antenna on a ceramic substrate having a relatively small thermal expansion, it becomes possible to directly mount a package or the like and house the semiconductor element in a formed cavity, thereby achieving higher reliability and lower cost. Becomes possible.
[0008]
Therefore, as shown in FIG. 11, the applicant of the present invention has proposed a columnar dielectric in which all or a part of the side surface of a cylindrical dielectric is covered with an electromagnetic wave shield and has an opening for emitting a high-frequency signal to space. Type dielectric resonator 110 and a waveguide or a dielectric waveguide 120 for supplying power to the cylindrical dielectric resonator 110, and the waveguide or the dielectric waveguide 120 has an H-plane conductor surface. A cylindrical dielectric resonator 110 is mounted, and a substantially circular or polygonal shape is provided at a position facing the center of the opening of the cylindrical dielectric resonator 110 in the H-plane conductor of the waveguide or the dielectric waveguide 120. An array antenna in which an aperture antenna formed by feeding a high-frequency signal from a waveguide or a dielectric waveguide 120 to a cylindrical dielectric resonator 120 through the coupling hole 121 is formed in an array shape. Proposed antenna No. -353,727).
[0009]
This array antenna is not only circularly polarized, but can also be made linearly polarized by changing the coupling position between the feed line and the radiating element, and can be manufactured at low cost.
[0010]
[Patent Document 1]
JP-A-2002-353727
[0011]
[Problems to be solved by the invention]
Generally, in the case of an array antenna, mutual coupling occurs between radiating elements. When the polarization characteristic is linear polarization, the influence of mutual coupling is not a concern. However, when the polarization characteristic is circular polarization, the axial ratio is degraded. In particular, when the distance between the radiating elements is different between the horizontal direction and the vertical direction, the axial ratio is greatly deteriorated. For example, the radiating element alone has elliptical polarization as a whole despite the fact that antennas having an axial ratio of 0 are arranged.
[0012]
FIG. 12 shows a simulation result of a vertical arrangement of three radiating elements designed to have an axial ratio of 0, that is, a 3 × 1 array antenna. The electric field vector changes when the phases are 0 °, 30 °, 60 °, and 90 ° are shown in order from the left. As can be seen from FIG. 12, the radiating element alone clearly has elliptical polarization despite the fact that antennas having an axial ratio of 0 are arranged. In addition, the element at the center is affected by the elements on both sides, and the axial ratio is particularly greatly deteriorated.
[0013]
The present invention has been devised to solve such a conventional problem, and an object of the present invention is to obtain a good axial ratio characteristic of the entire array antenna even when there is mutual coupling between radiating elements. An object of the present invention is to provide a circularly polarized array antenna and a substrate with an antenna.
[0014]
[Means for Solving the Problems]
The present inventor has repeatedly studied the above-mentioned problems, and as a result, by making the polarization radiated from the radiating element an elliptical polarization so as to cancel the deviation of the axial ratio due to mutual coupling between the radiating elements. It has been found that good axial ratio characteristics can be obtained as circularly polarized waves in the entire array antenna. In addition, it has been found that, by forming the radiating element as a cylindrical dielectric resonator and making the opening thereof an elliptical shape, it is possible to easily adjust the axial ratio of the radiating element and the inclination of its axis.
[0015]
That is, in the circularly polarized array antenna of the present invention, in a circularly polarized array antenna in which a plurality of radiating elements are arranged in an array on a predetermined substrate surface, a part or all of the radiating elements are individually Is an elliptical polarization, and the overall axial ratio is 3 dB or less. According to such a circularly polarized array antenna, it is possible to improve the axial ratio of the entire array antenna by adjusting the polarization characteristics of the radiating element so as to cancel the deviation of the axial ratio due to the interaction between the radiating elements. it can. In other words, the individual radiating elements are designed such that the axis ratio of the elliptical polarization and the inclination of the axis are set to predetermined values, and are designed to be circularly polarized as a whole.
[0016]
Further, the radiating element is formed of a columnar dielectric resonator having all or a part of the side surface of the columnar dielectric covered with metal, and having an elliptical opening for radiating a high-frequency signal into space. Thus, the axial ratio of the radiating element and the inclination of the axis can be easily adjusted.
[0017]
Further, by providing a feed line of the array antenna with a waveguide or a dielectric waveguide, a low-loss antenna can be provided.
[0018]
On the other hand, a substrate with an antenna according to the present invention includes a dielectric substrate, a feed line provided in the dielectric substrate, which can transmit a high-frequency signal, and a plurality of radiating elements connected to the feed line arranged in an array. In the antenna substrate provided with the formed circularly polarized wave array antenna, it is required that the polarization characteristics of a part or all of the radiating elements are elliptically polarized, and the overall axial ratio is 3 dB or less. It is a feature. Further, the power supply line is formed from an upper main conductor layer and a lower main conductor layer formed with a dielectric material interposed therebetween, and two rows of through conductor groups electrically connecting the upper main conductor layer and the lower main conductor layer. A sub-conductor layer formed by a dielectric waveguide surrounded by a conductor wall comprising: a plurality of through-conductor groups in two rows provided between an upper main conductor layer and a lower main conductor layer in parallel with the main conductor layer. Can be easily formed by a conventionally known multi-layering technique.
[0019]
Still further, the radiating element includes an upper main conductor layer having an opening formed on a surface of a dielectric substrate formed by stacking a plurality of dielectric layers, and a lower main conductor layer formed at a position facing the opening. A body layer and an antenna conductor wall formed in the dielectric substrate around the opening and having a plurality of through conductors that electrically connect the upper main conductor layer and the lower main conductor layer at a predetermined interval. By forming the antenna by the surrounded dielectric resonator, the antenna can be integrally formed together with the feed line made of the dielectric waveguide by using a multilayer technique.
[0020]
Still further, at least one signal amplifier, at least one switch, circulator, or diplexer is mounted on the back surface of the dielectric substrate. Further, a cavity for accommodating a semiconductor element is formed on a back surface of the dielectric substrate. Thus, since the circularly polarized array antenna, other elements, and the substrate can be provided integrally, a compact antenna integrated module can be realized.
[0021]
Further, when the dielectric substrate is made of low-temperature fired ceramics and the conductor is made of a conductive material containing silver or copper as a main component, it is possible to reduce the loss and improve the antenna characteristics. .
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is a diagram illustrating the principle of the axial ratio adjustment. FIG. 1A is a diagram showing a case where the polarization characteristics are shifted due to mutual coupling of the radiation elements. When the axial ratio is Ar and the inclination of the major axis of the elliptical polarization is shifted to θ due to mutual coupling between the radiating elements (a), the axial ratio of the radiating element is Ar and the inclination of the major axis of the elliptical polarization is Ar. When the angle is set to θ + 90 ° (b), it is understood that the combined polarization becomes a circular polarization (c).
[0024]
2A and 2B show a basic structure of an example of a radiating element used in the present invention. FIG. 2A is a perspective view, and FIG. 2B is a sectional view taken along line XX of FIG. In FIG. 2, reference numeral 1 denotes a cylindrical dielectric resonator. The side surface and the upper surface of the cylindrical dielectric 1a are covered with a metal layer 1b, and the upper surface has an elliptical opening 1c for radiating a high-frequency signal into space. Is provided. Reference numeral 2 denotes a waveguide-type feed line of a waveguide or a dielectric waveguide. According to FIG. 2, the upper surface, the lower surface, and the side surface of the dielectric 2a are covered with the conductor 2b. The cylindrical dielectric resonator 1 is arranged on the waveguide type feed line 2, and the conductor on the lower surface of the cylindrical dielectric resonator 1 and the upper surface of the waveguide type feed line 2 are shared. . The shared conductor is provided with a coupling hole 3 for coupling the cylindrical dielectric resonator 1 and the waveguide type feed line 2.
[0025]
At this time, the lowest order coupling mode of the coupling hole 3 and the cylindrical dielectric resonator 1 is such that the conductor layer surrounds the coupling hole 3 in a circular shape as shown in FIG. Generates a mode similar to the resonance mode (TE111) of the 1/4 dielectric cylinder resonator, and the lowest-order resonance frequency of the mode is given by the following equation (1).
[0026]
(Equation 1)
f = 150 / ε ^1/2 × ｛(1.841 / πd) ² + (1 / 2t) ² ｝ ^1/2 Here, f is the resonance frequency (GHz), d is the diameter (mm) of the dielectric resonator, t is the thickness (mm) of the dielectric resonator, and ε is the relative permittivity.
[0027]
However, since power is supplied to the cylindrical dielectric resonator 1 from the coupling hole 3, the resonance frequency is affected by the size of the coupling hole 3.
[0028]
Further, in the embodiment of the present invention, the space filled with the above-described dielectric material is used as the dielectric resonator 1, so that its thickness t is λ / 8 to λ / λ with respect to the signal wavelength λ of the high-frequency signal. It is desirable to set within the range of 2.
[0029]
An ordinary circularly polarized antenna is designed so that the axis ratio of polarized light radiated from the radiating element is zero. That is, in the radiation element including the cylindrical dielectric resonator 1 of FIG. 2, the opening 1c has a circular shape.
[0030]
However, in the present invention, in order to cancel the mutual coupling between the radiating elements, the polarization radiated from the radiating element is set to the elliptical polarization. Therefore, the structure of the radiating element used in the present invention needs to be a structure in which the axial ratio can be easily adjusted and the inclination of the major axis of the elliptical polarization can be arbitrarily changed. Further, it is desirable that the power radiated from the antenna hardly changes by adjusting the axial ratio.
[0031]
The radiating element composed of the cylindrical dielectric resonator 1 of FIG. 1 satisfies this requirement. That is, by making the opening 1c of the cylindrical dielectric resonator 1 elliptical, the axial ratio of the antenna can be adjusted at the design stage, and further, by changing the rotation angle of the ellipse, the elliptical polarization can be obtained. The inclination of the long axis can be changed freely. In addition, by making the area of the elliptical opening 1c constant, the power radiated from the antenna can be adjusted with little change.
[0032]
If the radiating element is a waveguide slot antenna, it is possible to make the polarization elliptical, but it is not possible to adjust the long axis of the polarization radiated therefrom. For this reason, it is difficult to adjust the axial ratio as in the present invention.
[0033]
FIG. 3 is a perspective view showing an example of a circularly polarized array antenna using the radiating element of FIG. 1 is a cylindrical dielectric resonator serving as a radiating element, 2 is a waveguide type feeding circuit, 1c1c is an opening, and 3 is a coupling between the cylindrical dielectric resonator radiating element 1 and the waveguide type feeding circuit 2. A coupling hole 6 is a waveguide-type second power supply circuit for supplying power to a plurality of waveguide-type first power supply circuits 2 and 61 is a waveguide-type second power supply circuit 6 and a waveguide-type second power supply circuit. A slot for coupling to the power supply circuit 2 is provided. Reference numeral 62 denotes an antenna port formed at an end of the waveguide type second power supply circuit 6.
[0034]
In FIG. 3, the high-frequency signal input from the antenna port 62 repeats branching, and power is supplied to the center of six waveguide-type power supply circuits 2 in the group of slots 61. The high-frequency signal coupled at the center of the waveguide-type first power supply circuit 2 branches right and left, and is coupled to one group of five (a total of ten left and right) cylindrical dielectric resonators. Thereafter, linearly polarized light or circularly polarized light is radiated from the opening 1c of the cylindrical dielectric resonator 1. In this case, in order to control the radiation pattern, it is necessary to adjust the amount of coupling between each of the cylindrical dielectric resonators 1 and the waveguide type feed circuit 2. This adjustment can be made by changing the size of the coupling hole 3, the diameter of the opening 1c above the dielectric resonator 1, or the diameter d of the cylindrical dielectric resonator 1.
[0035]
According to the present invention, as shown in FIG. 3, a part or all of the radiating elements in each of the cylindrical dielectric resonators 1 have an opening 1c as shown in FIG. By arranging the devices to emit elliptically polarized waves, the overall axial ratio is reduced to 3 dB or less, particularly to 1.5 dB or less at the center frequency. If this axis ratio is larger than 3 dB, the reception energy of the reverse polarization component increases when considering reception, and the merit of circular polarization decreases.
[0036]
FIGS. 4A and 4B show an example of a substrate with an antenna in which the circularly polarized array antenna radiating element of the present invention is formed in a dielectric substrate. FIG. 4A is a plan view of one radiating element, and FIG. (A) is a cross-sectional view taken along line XX, and (c) is a cross-sectional view of the entire antenna-equipped substrate of (a) and (b).
[0037]
In FIG. 4, reference numeral 1 denotes a dielectric resonator serving as a radiation element, 2 denotes a waveguide type feed circuit, 1c1c denotes an opening, and 3 denotes a coupling hole for connecting the dielectric resonator 1 and the waveguide type feed circuit 2. It is.
[0038]
According to the substrate with an antenna of FIG. 4, the dielectric resonator 1 serving as a radiating element is formed on the resonator portion dielectric substrate 51 formed by laminating the dielectric layers 51a and 51b. The upper main conductor layer 11 is formed on the upper surface of the dielectric substrate 51, and the lower main conductor layer 13 is formed on the lower surface.
[0039]
Further, the waveguide type feed line 2 is formed on a feed portion dielectric substrate 52 formed by laminating dielectric layers 52a and 52b. The upper main conductor layer 21 is formed on the upper surface of the dielectric substrate 52, and the lower main conductor layer 23 is formed on the lower surface.
[0040]
In the drawing, the resonator unit lower main conductor layer 13 and the feed unit upper main conductor layer 21 are used in common.
[0041]
The opening 1c is formed by providing a non-conductor-forming portion in the resonator portion upper main conductor layer 11, and the coupling hole 3 is formed by providing a conductor-free portion in the resonator portion lower main conductor layer 13. I have.
[0042]
Numeral 14 is formed in the resonator dielectric substrate 51 around the opening 1c so as to electrically connect the resonator upper main conductor layer 11 and the resonator lower main conductor layer 13 at a predetermined interval. Are formed in the plurality of resonator portion penetrating conductors. The plurality of through-cavity conductors 14 are arranged at a repetition interval of less than half the signal wavelength of the high-frequency signal. The repetition interval is not necessarily limited to a constant value, but may be set to a combination of various values that are less than half the signal wavelength. In addition, double and triple may be provided.
[0043]
Numeral 12 is formed between the resonator portion dielectric layers 51a and 51b in parallel with the resonator portion upper main conductor layer 11 and the resonator portion lower main conductor layer 13, and connects the plurality of resonator portion through conductors 14 to the resonator portion dielectric layer. A resonator sub-conductor layer that is electrically connected between the body layers 51a and 51b. The resonator sub-conductor layer 12 is provided with a conductor non-formed portion having a shape similar to that of the opening 1c, and is formed as a single layer or a plurality of layers as necessary. A lattice-shaped resonator conductor side wall is formed in the body substrate 51. Then, it is surrounded by a resonator portion upper main conductor layer 11, a resonator portion lower main conductor layer 13, a lattice-shaped resonator conductor wall composed of a plurality of resonator portion through conductors 14, and a resonator portion sub-conductor layer 12, The dielectric resonator 1 is formed in the resonator portion dielectric substrate 51 by the space filled with the dielectric.
[0044]
Reference numerals 24a and 24b are formed in the feeder dielectric substrate 52, and electrically connect the feeder upper main conductor layer 21 (feeder lower main conductor layer 13) and the feeder unit lower main conductor layer 23 at a predetermined interval. It is a plurality of feeder through conductors formed to be connected. The plurality of feed-through conductors 24a and 24b are arranged at a repetition interval of less than λ / 2, where λ is the signal wavelength of the high-frequency signal in the dielectric substrate. The repetition interval is not necessarily limited to a constant value, but may be set to a combination of various values that are less than half the signal wavelength. In addition, in the drawing, it is formed in one row, but it may be formed in a plurality of rows.
[0045]
22 is formed between the feeder dielectric layers 52a and 52b in parallel with the feeder upper main conductor layer 21 and the feeder lower main conductor layer 23, and connects the feeder through-conductors 24a and 24b to the feeder dielectric layer 52a. , 52b. The feeder sub-conductor layer 22 is not formed between the feeder feedthrough conductor groups 24a and 24b, but is formed as a single layer or a plurality of layers as necessary, and together with the feeder feedthrough conductors 24a and 24b. A conductor wall is formed therein. It is surrounded by the feeder upper main conductor layer 21, the feeder lower main conductor layer 23, and the lattice-shaped conductor wall including the feeder through conductors 24 a and 24 b and the feeder sub-conductor layer 22, and is filled with a dielectric. The space provided forms a dielectric waveguide having a rectangular cross section in the feeder dielectric substrate 52. In particular, when this dielectric waveguide is used in a single mode, the distance w between the feeder through-conductor groups 24a and 24b is set to λ / 2 <w <λ. In addition, the power supply part dielectric layer 52 may be a single layer, and in this case, the power supply part sub-conductor layer 22 is not formed.
[0046]
By arranging the resonator-unit through conductors 14 and the resonator-unit sub-conductor layer 12 formed in the resonator-unit dielectric substrate 51 around the opening 1c of the resonator-unit upper main conductor layer 11 in a lattice pattern, A conductor wall constituting a side wall of the dielectric resonator 1 is formed, and thereby, an electric wall is arranged in the resonator portion dielectric substrate 51 so as to surround the coupling hole 3. The opening 1c is formed by the resonator upper conductor layer 11 having the opening 1c, the resonator lower main conductor layer 13 having the coupling hole 3, the plurality of resonator penetrating conductors 14, and the resonator sub conductor layer 12. A dielectric resonator 1 is formed by a space filled with a columnar dielectric surrounded by a resonator portion conductor side wall formed around the dielectric resonator, and thereby the columnar dielectric resonator 1 as a radiating element is insulated. It is formed in the body substrate 51.
[0047]
In addition, the feeder upper main conductor layer 21 (or the resonator lower main conductor layer 13), the feeder lower main conductor layer 23, the feeder feedthrough conductors 24a and 24b formed in the feeder dielectric substrate 52, and the feeder A conductor wall is formed by arranging the sub-conductor layers 22 in a grid pattern, and the rectangular dielectric waveguide 2 is formed in the dielectric substrate 52.
[0048]
The electromagnetic wave of the high-frequency signal radiated from the waveguide-type feed line 2 to the opening 1 c through the coupling hole 3, due to the presence of the dielectric resonator 1, the pair of main conductor layers 11 outside the space, The light is radiated from the opening 1c to free space without propagating between the holes 13.
[0049]
In the substrate with an antenna of the present invention, based on the arrangement shown in FIG. 3, a radiation element including a plurality of dielectric resonators 1 is arrayed on the waveguide-type first feed line 2 inside the dielectric substrates 51 and 52. The waveguide-type first feeder line 2 is connected to the waveguide-type second feeder line 6 to form a circularly polarized array antenna having the structure shown in FIG.
[0050]
5A and 5B show an example in which active elements are mounted on a substrate having the circularly polarized array antenna of FIG. 4, wherein FIG. 5A is a perspective view, and FIG. 5B is a sectional view taken along line Z1-Z1 of FIG.
[0051]
In FIG. 5, reference numeral 81 denotes a connection part that couples the antenna port 62 to the surface circuit, 71 denotes a signal amplifier, 72 denotes a filter, 73 denotes a mixer, 74 denotes a high-frequency signal generator, and 82 denotes an IF signal IF port.
[0052]
For example, the IF signal input from the IF port 82 is mixed with the carrier signal generated by the high-frequency signal generator 74 by the mixer 73, and after the high-frequency components such as out-of-band harmonics are cut by the filter 72, the signal is amplified by the signal amplifier. The signal is amplified at 71 and input to the antenna substrate via the connection unit 81. It is not necessary that all the active elements 71 to 74 be mounted on the antenna substrate 5, but at least the form of the antenna module in which the signal amplifier 71 is mounted on the antenna substrate 5, particularly when the signal wavelength uses the millimeter wave band, The advantage is great in terms of transmission loss.
[0053]
6A and 6B show another example in which active elements are mounted on a substrate having the circularly polarized array antenna of FIG. 4, wherein FIG. 6A is a perspective view, and FIG. 6B is a sectional view of FIG. It is. Parts similar to those shown in FIG. 5 are denoted by the same reference numerals.
[0054]
In FIG. 6, reference numeral 75 denotes a switch such as a switch, a circulator, or a diplexer; 82a, an IF input port; and 82b, an IF output port.
[0055]
The IF signal input from the IF input port 82a is mixed with the carrier signal generated by the high frequency signal generator 74 by the mixer 73a, and after the high frequency components such as harmonics outside the band are cut by the filter 72a, the high output signal The signal is amplified by the amplifier 71a, and a signal is sent only to the connection portion 81 by the signal switch 75 such as a switch, a circulator, or a diplexer, and is input to the antenna substrate 5. On the other hand, the signal received by the antenna substrate 5 and reaching the connection section 81 is sent to only the low noise signal amplifier 71b by the signal switch 75, and the signal outside the band is cut by the filter 72b. The signal generated by the signal generator 74 is mixed with the mixer 73b, and only the IF signal is extracted. Thereafter, the data is output from the IF output port 82b.
[0056]
By arranging the signal switch 75 in this way, an antenna module that can be used for both transmission and reception can be provided.
[0057]
7A and 7B show an example in which a semiconductor element is mounted in a cavity on a substrate provided with the circularly polarized array antenna of FIG. 4, wherein FIG. 7A is a perspective view, and FIG. 7B is a perspective view, and FIG. It is -Z3 sectional drawing. Parts similar to those shown in FIG. 6 are denoted by the same reference numerals. In FIG. 7, 7 is a semiconductor element, and 9 is a cavity. The semiconductor element 7 may have a single function such as a switch or a signal amplifier, or may be an integrated version of the functional element group shown in FIG. 5 or FIG.
[0058]
By forming the cavity 9 on the back surface of the antenna-equipped substrate as described above, the semiconductor element 7 can be accommodated in the cavity 9, so that an antenna module with high characteristics and low cost can be realized.
[0059]
The dielectric substrates 51 and 52 in the example of the above embodiment can be formed of ceramics, synthetic resin, or a composite material of ceramics-synthetic resin as an insulating material. Preferably, the ceramics include alumina, AlN, silicon nitride, glass ceramics, and the like. Also, the resonance section upper main conductor layer 11, the resonance section lower main conductor layer 13 (feeding section upper main conductor layer 21), the resonance section sub-conductor layer 12, the feeding section lower main conductor layer 23, the feeding section sub-conductor layer 22, and the like. The conductor layer, the via conductor, and the through-hole conductor are formed of a conductor material such as copper, silver, tungsten, and molybdenum.
[0060]
These are all in accordance with a well-known multilayer substrate manufacturing technique, after forming the above-mentioned insulating material into a sheet, forming a paste or a metal foil of the above-mentioned conductive material on the sheet surface by patterning, and forming a via conductor or a through-hole conductor. A plurality of sheets are formed by forming through holes in a sheet, filling the sheet with a conductive paste, or performing plating. Thereafter, in the case of ceramics, it is baked to a predetermined temperature, and in the case of containing a synthetic resin, it is thermally cured, so that a substrate with an antenna having a multilayer structure can be manufactured.
[0061]
In particular, by using a low-temperature fired ceramic that can use a low-resistance metallized layer such as copper, silver, or gold as a dielectric material, transmission loss is reduced and antenna characteristics are improved.
[0062]
The material for the low-temperature fired ceramic is not particularly limited as long as it can be fired at a temperature of 1000 ° C. or less. And the like, in which a ceramic filler such as, is added at a ratio of 30 to 80% by mass.
[0063]
【Example】
Next, a specific example of the circularly polarized array antenna of the present invention will be described.
[0064]
FIG. 8 is an example showing the axial ratio when the aperture of the radiating element is made elliptical and the inclination of the major axis of the polarized light to be emitted.
[0065]
For the dielectric layers 51 and 52, a borosilicate glass-silica glass ceramic material having a relative dielectric constant of 4.9 is used. The thickness t of the dielectric resonator 1 is 0.6 mm, and the diameter d of the dielectric resonator 1 is φ2.12 mm, the size of the waveguide type feed line 2 is (w, h) = (1.82 mm, 0.6 mm), and the center position of the elliptical coupling hole 3 is the conductor wall 24 a of the waveguide type feed line 2. From 0.52 mm.
[0066]
Here, the area of the elliptical opening 1c is 2.66 mm. ² Is constant. The frequency was evaluated at 62.5 GHz. In the figure, black circles indicate the axial ratio, and white circles indicate the inclination of the long axis in elliptical polarization. FIG. 8 shows that the axial ratio can be changed from 0 to 4 by changing the value of a from 0.88 mm to 0.96 mm. When a = 0.92, the opening is a perfect circle and the axial ratio is also 0.
[0067]
FIG. 9 is a characteristic diagram when the method described in the present invention is not applied to a 6 × 8 element array antenna, and FIG. 10 is a characteristic diagram when the axial ratio is corrected according to the present invention.
[0068]
First, all the radiating elements were adjusted to an axial ratio of 0, an array was designed, and a radiation pattern was calculated using simulation by the FDTD method. The axial ratio at this time was 4.9 dB as shown in FIG. 9, and the inclination of the long axis of the polarization at that time was −40 °. Therefore, FIG. 10 shows the result obtained by setting the axis ratio of the radiating element to 4.9 dB and setting the inclination of the major axis to +50, and performing the simulation again. As a result, the axial ratio has been improved to 1.2 dB. Further, the result that the side lobe level was improved by about 3 dB was obtained.
[0069]
【The invention's effect】
As described in detail above, according to the present invention, the circularly polarized array antenna of the present invention is configured such that the radiating element has an elliptical polarization so as to cancel the deviation of the axial ratio due to the mutual coupling of the radiating elements. Good polarization characteristics can be obtained as a whole.
[0070]
Further, by making the radiating element a cylindrical resonator and making its opening elliptical, the axial ratio can be adjusted and the inclination of the long axis of the elliptically polarized light to be radiated can be freely changed.
[0071]
Further, a dielectric waveguide capable of transmitting a high-frequency signal and an opening for covering all or a part of the side surface of the cylindrical dielectric with metal and radiating the high-frequency signal to a space are provided in the dielectric substrate. Forming a coupling hole in the H-plane conductor of the dielectric waveguide at a position facing the center of the opening of the cylindrical dielectric resonator; A high-frequency signal is supplied from the dielectric waveguide to the cylindrical dielectric resonator through the hole, so that an active element or a signal switch is directly mounted or a cavity is formed on the back surface of the dielectric substrate. In addition, a substrate with an antenna can be provided which is small, highly reliable, and low in cost.
[0072]
Furthermore, when the dielectric substrate forming the antenna substrate is made of low-temperature fired ceramics, a low-resistance metallized layer of copper, silver, or the like can be used, thereby reducing transmission loss and improving antenna characteristics.
[Brief description of the drawings]
FIG. 1 is a diagram showing the principle of antenna axial ratio correction by mutual coupling between radiating elements in a circularly polarized array antenna of the present invention.
FIGS. 2A and 2B show a basic structure of an example of a radiating element used in the present invention. FIG. 2A is a perspective view, and FIG. 2B is a sectional view taken along line XX of FIG.
FIG. 3 is a perspective view showing an example of a circularly polarized array antenna using the radiating element of FIG. 1 and an example for explaining a feeding structure thereof.
4A and 4B show an example of a substrate with an antenna in which a circularly polarized array antenna radiating element of the present invention is formed in a dielectric substrate. FIG. 4A is a plan view of one radiating element, and FIG. (A) is a cross-sectional view taken along line XX, and (c) is a cross-sectional view of the entire antenna-equipped substrate of (a) and (b).
5A and 5B show an example in which an active element is mounted on a substrate having the circularly polarized array antenna of FIG. 4; FIG. 5A is a perspective view, and FIG. 5B is a sectional view taken along line Z1-Z1 of FIG. .
6A and 6B show another example in which active elements are mounted on a substrate provided with the circularly polarized array antenna of FIG. 4, wherein FIG. 6A is a perspective view and FIG. 6B is a sectional view taken along line Z2-Z2 of FIG. It is.
7A and 7B show an example in which a semiconductor element is mounted in a cavity on a substrate provided with the circularly polarized array antenna of FIG. 4; FIG. 7A is a perspective view, and FIG. It is -Z3 sectional drawing.
FIG. 8 is a diagram showing the relationship between the axial ratio when the aperture of the radiating element is made elliptical and the inclination of the major axis of the emitted polarized light.
FIG. 9 shows a characteristic diagram of a conventional 6 × 8 element array antenna.
FIG. 10 shows a characteristic diagram of a 6 × 8 element array antenna with an axial ratio corrected according to the present invention.
FIG. 11 is a perspective view for explaining a conventional circularly polarized array antenna and a feed structure thereof.
FIG. 12 is a diagram showing a simulation result of polarization characteristics of a conventional circularly polarized array antenna.
[Explanation of symbols]
1 Dielectric resonator
11 Resonator upper main conductor layer
12 Resonator sub-conductor layer
13 Lower main conductor layer of resonator part
14 Through-hole conductor
2 Waveguide feed line
21 Main conductor layer at upper part of power supply
22 Feeder sub-conductor layer
23 Lower conductor layer of power supply section
24 Feed-through conductor
1c Opening
3 coupling holes
5 Antenna board
51 Resonator dielectric substrate
52 feeder dielectric substrate
6. Waveguide-type second feed line
61 slots
62 antenna port
7 Semiconductor elements
71 signal amplifier
72 filters
73 mixer
74 high frequency signal generator
75 Signal switch
81 Connection
82 IF port
9 cavities

Claims (12)

On a predetermined substrate surface, in a circularly polarized array antenna in which a plurality of radiating elements are arrayed and formed in an array, the polarization characteristics of some or all of the radiating elements are elliptically polarized, A circularly polarized array antenna, wherein the entire axial ratio is 3 dB or less. 2. The circularly polarized array antenna according to claim 1, wherein the individual radiating elements are designed to adjust the axial ratio of the elliptical polarization and the inclination of the axis so that the individual radiating elements become circular polarization as a whole. . The radiating element is formed of a columnar dielectric resonator in which all or a part of the side surface of the columnar dielectric is covered with a metal and has an elliptical opening for radiating a high-frequency signal to a space. 3. The circularly polarized array antenna according to claim 1, wherein: The circularly polarized array antenna according to any one of claims 1 to 3, wherein power is supplied to the radiating element by a waveguide or a dielectric waveguide. A dielectric substrate, a feed line provided in the dielectric substrate and capable of transmitting high-frequency signals, and a circularly polarized array antenna in which a plurality of radiating elements connected to the feed line are arranged in an array. An antenna substrate according to claim 1, wherein the polarization characteristics of a part or all of the radiating elements are elliptically polarized, and the overall axial ratio is 3 dB or less. A conductor comprising an upper main conductor layer and a lower main conductor layer formed with a dielectric interposed therebetween, and two rows of through conductor groups electrically connecting the upper main conductor layer and the lower main conductor layer 6. The antenna-equipped substrate according to claim 5, comprising a dielectric waveguide surrounded by a wall. 7. The two rows of through conductor groups are electrically connected between an upper main conductor layer and a lower main conductor layer by a sub-conductor layer provided in parallel with the main conductor layer. Substrate with antenna. The radiating element, an upper main conductor layer having an opening formed on the surface of a dielectric substrate formed by laminating a plurality of dielectric layers, and a lower main conductor layer formed at a position facing the opening And an antenna conductor wall formed in the dielectric substrate around the opening and having a plurality of through conductors electrically connecting the upper main conductor layer and the lower main conductor layer at a predetermined interval. The substrate with an antenna according to any one of claims 5 to 7, wherein the substrate is a dielectric resonator. The substrate with an antenna according to any one of claims 5 to 8, wherein at least one signal amplifier is mounted on a back surface of the dielectric substrate. The substrate with an antenna according to any one of claims 5 to 9, wherein at least one switch, circulator, or diplexer is mounted on the back surface of the dielectric substrate. The substrate with an antenna according to any one of claims 5 to 10, wherein a cavity for accommodating a semiconductor element is formed on a back surface of the dielectric substrate. The substrate with an antenna according to any one of claims 5 to 11, wherein the dielectric substrate is made of low-temperature fired ceramics, and the conductor is made of a conductive material containing silver or copper as a main component. .

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