JP2006025035A - Circular polarized wave microstrip antenna and multifrequency shared antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circular polarized wave microstrip antenna improved in characteristics of a circular polarized wave by suppressing influence of a cross-polarized wave component when the antenna is fed by a two-point feed system. <P>SOLUTION: The circular polarized wave microstrip antenna of the present invention is equipped with: a dielectric substrate 12 formed of a dielectric material to a specified thickness; a batch conductor 11 arranged on one surface of the dielectric substrate 12; a ground conductor 13 arranged on the other surface of the dielectric substrate 12; a 1st feed part 14 which is arranged in a direction A when viewed from the center C of the batch conductor 11 to feed the batch conductor 11; a 2nd feed part 15 which is arranged in a direction B orthogonal to the direction A when viewed from the center C of the batch conductor 11 to feed the batch conductor 11 with nearly the same amplitude with the 1st feed part 13 in nearly 90° different phase; and perturbation parts 11a and 11b which are formed on the batch conductor 11 to adjust degenerative separation quantities of excitation by the 1st and 2nd feed parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a circularly polarized microstrip antenna capable of exciting circularly polarized waves, and in particular, by controlling the influence of cross-polarized components generated in a circularly polarized planar antenna of a two-point feed method, The present invention relates to a circularly polarized microstrip antenna capable of maintaining a wave antenna characteristic.

Conventionally, a two-point feed type circularly polarized microstrip antenna is known as a planar antenna capable of exciting circularly polarized waves. This type of circularly polarized microstrip antenna includes a feeding means including a patch conductor as a radiating element and a feeding circuit that feeds the patch conductor. The patch conductor is provided with two power feeding portions arranged in two directions orthogonal to each other when viewed from the center of the patch. Each power feeding portion has an amplitude ratio of about 1: 1 and a phase difference of about 90 °. Power to be As a result, since the orthogonally polarized waves having the same amplitude and a phase difference of 90 ° are excited by the patch conductor, it is possible to perform the circularly polarized wave driving.
JP 2001-267835 A JP 2003-224416 A

  The conventional two-point feeding type circularly polarized microstrip antenna has a problem in that it causes an increase in cross-polarized components due to mutual coupling of two feeding parts. The influence of the cross-polarized wave component causes a deterioration of the axial ratio, which hinders maintaining good characteristics of the circularly polarized wave. On the other hand, in the above conventional configuration, a method for suppressing the influence of the cross polarization component has been proposed. For example, Patent Document 1 discloses a method of reducing cross polarization components by shifting the amplitude ratio of signals input to two power feeding units from 1: 1 or by shifting the phase difference from 90 °. Patent Document 2 discloses a method of setting two power feeding units at positions shifted from orthogonal directions when viewed from the patch center. Each of these methods can suppress the above-mentioned cross polarization component.

  However, the methods disclosed in Patent Documents 1 and 2 above all relate to power supply means such as the structure of the power supply unit and the structure of the power supply circuit. Therefore, when such a method is applied, the load on the design of the power supply means becomes large, and it becomes a problem that the characteristics of circular polarization cannot be easily optimized.

  In addition, when a circularly polarized microstrip antenna is incorporated in a device, the characteristics of circularly polarized waves may be adversely affected by the surrounding environment such as a circuit board, other functional parts, and cables. It is not easy to optimize the circularly polarized wave characteristics suitable for the surrounding environment such as those by the power feeding means.

  Therefore, the present invention has been made to solve these problems. When a two-point feeding method is employed in a circularly polarized microslip antenna, the cross-polarized component due to the mutual coupling of two feeding parts is reduced. An object of the present invention is to provide a circularly polarized microstrip antenna having good circular polarization characteristics by controlling the influence and performing suitable control even under the influence of the surrounding environment. .

  In order to solve the above problem, the circularly polarized microstrip antenna according to claim 1 is a circularly polarized microstrip antenna capable of exciting circularly polarized waves, wherein a dielectric material is formed with a predetermined thickness. A body substrate, a patch conductor disposed on one surface of the dielectric substrate, a ground conductor disposed on the other surface of the dielectric substrate, and a first conductor as viewed from the center of the patch conductor. A first power feeding unit that feeds power to the patch conductor, and a second direction that is orthogonal to the first direction when viewed from the center of the patch conductor, and has substantially the same amplitude and substantially the same as the first power feeding unit. A second power feeding portion that feeds the patch conductor with a phase different by 90 °, and a degenerate separation amount of excitation by the first and second power feeding portions formed on any one of the patch conductor, the ground conductor, and the dielectric substrate. The perturbation part to adjust Characterized in that it comprises.

  According to the present invention, when two-point power feeding is performed to the circularly polarized microstrip antenna and power is fed from the first power feeding unit and the second power feeding unit so as to have a phase of about 90 ° with substantially the same amplitude, the patch The conductor can be circularly polarized. At this time, in the excitation in the two directions connecting each feeding unit from the center of the patch, cross polarization components are generated due to the presence of the two feeding units. However, the amount of degenerate separation can be adjusted appropriately by changing the state of the perturbation unit. For example, the generated cross polarization component can be controlled. Therefore, it is possible to accurately prevent the deterioration of the axial ratio and the like accompanying the increase of the cross polarization component, and to keep the circular polarization characteristics favorable. In addition, the characteristics of circular polarization can be kept good by adjusting the degeneracy separation amount suitable under the influence of the surrounding environment. In this characteristic improvement method, there is no load that changes the design of the power feeding circuit or the like, and adjustment is performed only in the antenna portion, thereby realizing simplification of the design.

  A circularly polarized microstrip antenna according to a second aspect is the invention according to the first aspect, wherein the perturbation portion extends in the first direction and the second direction when viewed from the center of the patch conductor. It has a non-axisymmetric structure with respect to at least one of the straight lines.

  According to this invention, in addition to the operation of the above-described invention, since the perturbation part has a non-symmetrical structure with respect to the two directions viewing the two feeding parts from the center of the patch, by changing the shape and size, It is possible to freely adjust the amount of degenerate separation.

  A circularly polarized microstrip antenna according to a third aspect of the present invention is the first polarized wave according to the second aspect, wherein the perturbation unit is excited in a direction that forms an angle of approximately 45 ° with each of the two straight lines. And a phase difference between the second polarized wave orthogonal to the first polarized wave and the second polarized wave can be changed.

  According to the present invention, in addition to the operation of the above-described invention, when assuming two polarizations each having an angle of 45 ° with respect to two directions in which the two feeding parts are viewed from the patch center, for example, the polarizations thereof. By providing a perturbation section that can give a predetermined difference to the electrical length of the two, it is possible to easily design the adjustment of the phase difference, that is, the adjustment of the degenerate separation amount. Thereby, the characteristic of circular polarization can be improved easily and reliably.

  A circularly polarized microstrip antenna according to a fourth aspect is the invention according to the third aspect, wherein the perturbation section is along one of the first polarized wave and the second polarized wave, The patch conductor is formed at two positions facing each other across the center of the patch conductor.

  The circularly polarized microstrip antenna according to claim 5 is the invention according to claim 3, wherein the perturbation section is parallel to either the first polarization or the second polarization. It is formed at one position on a straight line passing through the center of the patch conductor.

  The circularly polarized microstrip antenna according to claim 6 is the invention according to any one of claims 1 to 5, wherein the perturbation portion is any one of the patch conductor, the ground conductor, and the dielectric substrate. It is the notch area or protrusion area | region formed in the predetermined position of the external shape of this.

  A circularly polarized microstrip antenna according to a seventh aspect of the present invention is the invention according to any one of the first to fifth aspects, wherein the perturbation part is formed at a substantially center of the patch conductor or the ground conductor. A slot having a shape.

  According to the invention described in each of the fourth to seventh aspects, the perturbation part applicable to the patch conductor, the ground conductor, and the dielectric substrate has various variations with respect to its position, shape, number, and the like. The optimum perturbation unit can be selected and employed according to the device configuration.

  The invention according to claim 8 is a multi-frequency shared antenna capable of transmitting and receiving a plurality of frequencies and capable of transmitting and receiving circularly polarized waves at at least one of the plurality of frequencies. A circularly polarized microstrip antenna according to any one of claims 1 to 7 is used for transmission / reception of at least one of the frequencies transmitted / received by the multi-frequency shared antenna.

  According to the present invention, even in a multi-frequency shared antenna that supports multi-frequency transmission / reception, the circular polarization characteristics can be kept good by using the antenna to which the present invention is applied for circular polarization transmission / reception.

  According to the present invention, the circularly polarized microstrip antenna that performs two-point feeding is provided with a perturbation unit for adjusting the amount of depolarization and separation of circularly polarized waves. In the excitation in the two directions to be connected, the cross polarization component generated due to the presence of the two power supply units can be suppressed by adjusting the degeneracy separation amount by the perturbation unit. Therefore, it is possible to accurately prevent the deterioration of the axial ratio and the like accompanying the increase of the cross polarization component, and to keep the circular polarization characteristics favorable. In addition, the circularly polarized wave characteristics can be kept good by adjusting the degeneracy separation amount even with the influence of the surrounding environment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the structure of a circularly polarized microstrip antenna according to this embodiment, and shows a plan view and a side view, respectively.

  As shown in the plan view of FIG. 1, a patch conductor 11 made of a square metal conductor is disposed on the upper surface of the dielectric substrate 12. Here, although the case where the shape of the patch conductor 11 is a square is shown, the patch conductor 11 having another shape such as a rectangle or a circle may be used depending on the situation. The dielectric substrate 12 is made of a dielectric material having a desired dielectric constant, and has an outer shape larger than that of the patch conductor 11 and is formed to have a predetermined thickness. Further, as shown in the side view of FIG. 1, a ground conductor 13 having a predetermined shape is disposed on the lower surface of the dielectric substrate 12, and the patch conductor 11 and the ground conductor 13 face each other with the dielectric substrate 12 interposed therebetween. It is arranged.

  On the upper plane of the dielectric substrate 12, a first power supply unit 14 and a second power supply unit 15 for supplying power to the patch conductor 11 are provided. The first power supply unit 14 and the second power supply unit 15 are configured to supply power to the patch conductor 11 by capacitive coupling. The first power supply line 14 a and the second power supply line that penetrate the dielectric substrate 12, respectively. It is connected to the power feeding circuit via 15a.

  As shown in FIG. 1, when viewed from the patch center C of the patch conductor 11, the first feeding point F <b> 1 set at the approximate center of the first feeding unit 14 is arranged on a straight line in the direction of the arrow A, and the second A feeding point F2 set at substantially the center of the feeding unit 15 is arranged on a straight line in the arrow B direction. The straight line in the A direction and the straight line in the B direction with the patch center C as a base point are in a relationship orthogonal to each other. With such an arrangement, the circularly polarized microstrip antenna is driven to be circularly polarized by inputting signals having the same amplitude and different phases from each other by 90 ° to the first feeder 14 and the second feeder 15. Is possible.

  The patch conductor 11 is formed with a perturbation portion 11a at one corner of a square outer shape, and a perturbation portion 11b at one corner facing the perturbation portion 11a across the patch center C. These two perturbation parts 11a and 11b are formed by cutting out a predetermined area of a square two corners. The perturbation portions 11a and 11b are not limited to being provided by notches as shown in FIG. 1, and can be formed in various forms. Details will be described later.

  In FIG. 1, in general, when the patch conductor 11 is excited without providing the perturbation units 11a and 11b, cross polarization occurs due to the positional relationship between the first power supply unit 14 and the second power supply unit 15, thereby There is a risk of degrading circularly polarized antenna characteristics such as ratio. On the other hand, in the present embodiment, as described above, the perturbation portions 11a and 11b are formed at two locations on the patch conductor 11, thereby preventing the deterioration of the antenna characteristics due to the influence of the cross polarization component which is a problem in the two-point feeding method. I am trying.

  Here, a mechanism that is advantageous in the configuration in which the perturbation portions 11a and 11b are provided as in the present invention compared to the configuration in which the general perturbation portions 11a and 11b are not provided will be described. The following describes various characteristics when a two-point-feed circularly polarized antenna is used as two one-point-feed linearly polarized antennas orthogonal to each other.

  First, as shown in FIG. 2A, a case where power is supplied from the first power supply unit 22 to a square patch conductor 21 without a general perturbation unit is considered. At this time, the excitation by the first power feeding unit 22 can be considered as a superposition of two orthogonal modes, the polarization φ1 and the polarization φ2, as shown in FIG. The directions of excitation of these polarizations φ1 and φ2 are assumed to form an angle of 45 ° with respect to the input signal in the A direction when the feeding point F1 is viewed from the patch center C. Here, assuming that there is no second feeding part (one-point feeding), the respective polarizations φ1 and φ2 have the same amplitude and phase when observed in the directions of φ1 and φ2, respectively. The resonance component 21 is composed purely of the A direction component, and no B direction component is generated. In such a state, the frequency characteristics of the radiation phase in the antenna zenith direction for the polarizations φ1 and φ2 are shown in FIG. Note that all the antenna characteristics shown below are in the antenna zenith direction. In FIG. 3A, it can be seen that the phases of the polarized waves φ1 and φ2 are substantially coincident. That is, in the case of one-point power feeding from the first power feeding unit 22, no problem due to cross polarization occurs.

  On the other hand, as shown in FIG. 2B, when there is a second power feeding unit 23 that does not perform power feeding, a frequency difference or a phase difference is generated between the modes of the polarizations φ1 and φ2. FIG. 3B shows the phase characteristics corresponding to FIG. 3A in this case. In FIG. 3B, it can be seen that, unlike FIG. 3A, the phases of the polarizations φ1 and φ2 are shifted. This is because the polarizations φ1 and φ2 are unintentionally degenerated and separated due to the positions of the first and second power feeding portions 22 and 23 being asymmetric with respect to the polarizations φ1 and φ2. It is.

  Therefore, when power is supplied from one of the first power supply units 22 in the two-point power supply configuration, in addition to the main polarization component in the A direction, the weak crossing in which the phase difference is about 90 ° in the B direction as the excitation component. A polarization component appears. Here, considering the case where power is fed only from the second power feeding unit 23, in addition to the main polarization component in the B direction, a weak cross-polarization in which the phase difference is about 90 ° in the A direction in addition to the main polarization component in the B direction. Wave component appears. Then, when two-point feeding with a phase difference of 90 ° is applied to the first feeding unit 22 and the second feeding unit 23 in FIG. 2B, that is, when circularly polarized driving is performed, the main polarization is in each of the A and B directions. One of the component and the cross polarization component can be intensified and the other can be in a destructive relationship. Therefore, under such circumstances, there is a difference between the antenna gains in the A direction and the B direction, and the axial ratio of the circularly polarized microstrip antenna is deteriorated.

  On the other hand, in the circularly polarized microstrip antenna of the present embodiment, it is intended to prevent the deterioration of the axial ratio by intentionally controlling the unintentional degenerate separation state that causes the above phenomenon. FIG. 4 first considers a case where the circularly polarized microstrip antenna of the present embodiment is fed by only the first feeding unit 14. When the excitation of the patch conductor 11 is considered as a superposition of the polarizations φ1 and φ2, one polarization φ1 is along the diagonal direction where the perturbation portions 11a and 11b are formed, and the other polarization φ2 is the perturbation portion 11a. , 11b are arranged along the diagonal direction.

  With such an arrangement, the perturbations 11a and 11b act so as to change the relative electrical lengths of one polarization φ1 and the other polarization φ2. Thereby, the resonance frequency difference and phase difference of the polarizations φ1 and φ2 can be changed. That is, in FIG. 4, when the adjustment amount according to the shape and size of the perturbations 11a and 11b is appropriately set with respect to the polarizations φ1 and φ2, the degeneracy separation can be suppressed, and the intersection appearing in the A direction and the B direction. It is possible to reduce the polarization component and optimize the circular polarization characteristics such as the axial ratio.

  FIG. 5 is a diagram showing the phase characteristics of the polarizations φ1 and φ2 by supplying power only from the first power supply unit 14 with the perturbation units 11a and 11b appropriately adjusted in FIG. ) Based on the same conditions as in (1). It can be seen that there is no phase shift as seen in FIG. 3B between the polarization modes φ1 and φ2. That is, FIG. 5 shows that it is actually possible to eliminate the phase difference by adding the perturbation units 11a and 11b, that is, to suppress degenerate separation.

  Next, FIG. 6 compares the above series of characteristics. When considering power supply from only the first power supply unit, (A) has no second power supply unit (FIGS. 2A, 3A), and (B) have a second power supply unit. (C) and (C) are those in which a second power feeding unit is present and a perturbation unit is provided (FIGS. 4 and 5). In each state, the phase difference representing the degenerate separation amount of the polarizations φ1 and φ2 described above and the gain of the cross polarization component generated due to the phase difference are plotted. Since (B), which is a general arrangement of two-point-feed circularly polarized microstrip antennas, is in a degenerated and separated state due to the presence of two feeding parts, a cross-polarized component is generated. On the other hand, (C), which is the arrangement of the two-point-feed circularly polarized microstrip antenna having the perturbation part of this embodiment, succeeds in suppressing degenerate separation and reducing cross-polarized components. Thereby, compared with the thing without a general perturbation part, in this embodiment, deterioration of circular polarization characteristics, such as an axial ratio, can be prevented.

  Next, FIG. 7 is a diagram showing the frequency characteristics of the axial ratio when two-point feeding circularly polarized wave driving is performed that is completely isolated from the circularly polarized microstrip antenna of the present embodiment. 7A shows characteristics when the perturbation units 14 and 15 of the present embodiment are provided (FIG. 4), and FIG. 7B shows a configuration without a general perturbation unit for comparison. The characteristic in the case of (FIG.2 (b)) is shown.

  Comparing the characteristics of FIG. 7A and FIG. 7B, it can be seen that the axial ratio can be generally reduced by the configuration of the present embodiment. This is because there is almost no difference in the gain between the polarizations in the A direction and the B direction in FIG. 7A compared to the difference in the polarization gains in the A direction and the B direction in FIG. Yes. In the present embodiment, the cross polarization component can be reduced as described above by the action of the perturbation units 11a and 11b, thereby reducing the difference in polarization gain between the A direction and the B direction and making the axial ratio close to zero. . Therefore, it is advantageous to adopt the configuration of the present embodiment in order to improve the characteristics of circular polarization at the time of two-point power feeding.

  Next, it will be described that the circularly polarized microstrip antenna according to the present embodiment is useful in mounting a wireless device or the like. In general, when an antenna is incorporated in a device such as a wireless device, there may be a situation in which cables and other functional parts exist around the circuit board and its surroundings and are arranged close to the antenna. The problem is that the antenna characteristics deteriorate due to the influence of the surrounding environment when the antenna is incorporated. With respect to such a problem, in the circularly polarized microstrip antenna of the present embodiment, characteristic degradation due to the influence of the surrounding environment can be improved by adjusting the perturbations 11a and 11b as described below.

  As an example in which the influence of the surrounding environment becomes a problem in this way, a case where a circularly polarized microstrip antenna is arranged asymmetrically on a circuit board will be taken up. FIG. 8 shows a state in which the patch conductor 11 and the dielectric substrate 12 are asymmetrically arranged with respect to the ground conductor 13 simulating the ground plane of the circuit board. That is, ideally, when the patch conductor 11 and the dielectric substrate 12 are arranged at substantially the center of the ground conductor 13, the influence of the surroundings acts symmetrically on the circularly polarized microstrip antenna, and the antenna characteristics are relatively good. To be kept. On the other hand, in the case of an asymmetrical arrangement as shown in FIG. 8, the influence of the surroundings varies depending on the direction, which causes a deterioration in antenna characteristics.

  In the present embodiment, even in the case of an asymmetrical arrangement as shown in FIG. 8, the antenna characteristics can be optimized by adjusting the perturbation units 11a and 11b. In the case of an asymmetrical arrangement as shown in FIG. 8, there is a difference in gain around the patch conductor 11 depending on whether the resonance direction is the A direction or the B direction, which may cause deterioration of the characteristics of circular polarization. Therefore, in order to eliminate the gain difference caused by the surrounding asymmetry, the shape of the perturbation portions 11a and 11b may be appropriately set to optimize the degeneracy separation amount and improve the characteristics of circular polarization.

  FIG. 9A shows the axial ratio characteristics in the antenna zenith direction when the perturbation portions 11a and 11b are optimized in a state where the circularly polarized microstrip antennas of this embodiment are arranged asymmetrically as shown in FIG. For comparison with FIG. 9 (a), FIG. 9 (b) shows characteristics when the configuration of FIG. 2 without the perturbation portions 11a and 11b is arranged asymmetrically as shown in FIG. In the general configuration in which the perturbation parts 11a and 11b shown in FIG. 9B are not provided, the axial ratio is considerably deteriorated, whereas in the configuration of this embodiment shown in FIG. The ratio is kept small enough. Incidentally, the shape of the perturbation parts 11a and 11b in FIG. 8 differs in the size to be cut out as compared with the shape in FIG. This is not a symmetrical arrangement, but in order to eliminate the gain difference newly caused by the asymmetric arrangement, the method for reducing the cross polarization component in FIG. It was used to adjust the gain and control the gain difference. Thus, the circularly polarized microstrip antenna of this embodiment is excellent in that the characteristics of circularly polarized waves can be optimized so as to suit the surrounding environment such as mounting on a circuit board.

  Next, in the circularly polarized microstrip antenna of this embodiment, various modifications can be made to the structure of the perturbation parts 11a and 11b as shown in FIG. Hereinafter, variations of the circularly polarized microstrip antenna having various perturbation units to which the present invention can be applied will be specifically described.

  FIG. 10 is a diagram showing a variation of a circularly polarized microstrip antenna using a square patch conductor 11. The three structures in FIGS. 10A, 10B, and 10C are all non-axisymmetric with respect to the A direction and the B direction in FIG. 1, but are rotated by 45 ° from the A direction and the B direction. This is an example in the case of line symmetry with respect to two directions. First, FIG. 10A shows an example having the same structure as FIG. FIG. 10B shows a structure having square perturbation portions 11 c and 11 d formed so as to protrude from two opposing corners of the square of the patch conductor 11. FIG. 10C shows a structure in which one rectangular slot is formed in the center of the patch conductor 11 and this slot is used as a perturbation part 11d.

  FIG. 11 is a diagram showing a variation of the circularly polarized microstrip antenna when the patch conductor 11 is circular instead of square. 11A, 11B, and 11C are non-symmetrical with respect to the A direction and the B direction in FIG. 1, as in FIG. 10, but 45 from the A direction and the B direction. It is line symmetric with respect to the two directions rotated. 11A shows a structure having perturbation parts 11e and 11f having the same shape as the perturbation parts 11a and 11b in FIG. 10A, and FIG. 11B shows the perturbation part in FIG. 10B. 11c and 11d shows a structure having the same shape of the perturbation parts 11g and 11h, and FIG. 11C shows a structure having the same shape of the perturbation part 11d of the perturbation part 11d of FIG. 10C.

  FIG. 12 is a diagram showing a variation of the circularly polarized microstrip antenna in the case where the perturbation part is provided only at one place using the square patch conductor 11. The structure shown in FIG. 12 is axisymmetric with respect to the A direction and the B direction, and is symmetrical with respect to one of the two directions rotated by 45 ° from the A direction and the B direction, and non-symmetric with respect to the other. FIG. 12A shows a structure having one perturbation portion 11j in which a square region at one corner of the patch conductor 11 is cut out. FIG. 12B shows a structure having one perturbation part 11k formed from one corner of the patch conductor 11 in the same shape as the perturbation parts 11c and 11d in FIG. 10B.

  FIG. 13 is a diagram showing a variation of the circularly polarized microstrip antenna in the case where the same symmetrical structure as in FIG. 12 is provided and the patch conductor 11 is circular instead of square. FIG. 13A shows a structure having one perturbation part 11l in which a predetermined region at one end of the patch conductor 11 is cut out. FIG. 13B shows a structure having one perturbation part 11m having the same shape as the perturbation part 11k in FIG.

  FIG. 14 shows a variation of the circularly polarized microstrip antenna when the patch conductor 11 is formed in an asymmetrical shape rather than a symmetric shape such as a square or a circle so that the patch conductor 11 itself has a perturbation structure. ing. Both are non-axisymmetric with respect to the A direction and the B direction, and are symmetrical with respect to two directions rotated by 45 ° from the A direction and the B direction. FIG. 14A shows a structure in which the shape of the patch conductor 11 is a parallelogram, and FIG. 14B shows a structure in which the shape of the patch conductor 11 is an ellipse.

  FIG. 15 shows that when the relationship between the physical length and the electrical length does not match in the A direction and the B direction, or when there is another adjustment requirement, the shape of the patch conductor 11 itself is, for example, rectangular, A variation of the circularly polarized microstrip antenna when the combined patch conductor 11 is formed is shown. In the structure of FIG. 15, it becomes asymmetric with respect to the A direction and the B direction. 15A shows a structure in which the rectangular patch conductor 11 has the perturbation portions 11n and 11o having the same shape as the perturbation portions 11a and 11b in FIG. 10A, and FIG. 15B shows the rectangular patch conductor. 11 shows a structure having a perturbation part 11p having the same shape as the perturbation part 11j in FIG.

  Next, in the circularly polarized microstrip antenna of this embodiment, in addition to the case where the patch conductor 11 is provided with a perturbation part as described above, the dielectric substrate 12 may be provided with a perturbation part. FIG. 16 is a diagram showing a variation of a circularly polarized microstrip antenna configured by providing a perturbation portion on the dielectric substrate 12.

  In FIG. 16A, perturbation portions 12a and 12b are provided at two opposite corners of the square dielectric substrate 12, and in FIG. 16B, a perturbation portion 12c is provided at one corner of the square dielectric substrate 12. In FIG. 16C, perturbation parts 12 d and 12 e that protrude from two opposing positions of the circular dielectric substrate 12 are provided. As described above, when the perturbation part is provided on the dielectric substrate 12, a formation method basically common to the case where the perturbation part is provided on the patch conductor 11 can be applied.

  Next, in the circularly polarized microstrip antenna of this embodiment, the ground conductor 13 may be further provided with a perturbation part. FIG. 17 is a diagram showing a variation of a circularly polarized microstrip antenna configured by providing a ground conductor 13 with a perturbation portion.

  In FIG. 17A, a perturbation portion 13a is provided at one corner of a square ground conductor 13, and in FIG. 17B, a perturbation portion 13b formed of a rectangular slot is provided at the center of the square ground conductor 13. . Thus, when providing a perturbation part in the ground conductor 13, the formation method common to the case where a perturbation part is provided in the patch conductor 11 is applicable.

  The ground conductor 13 is not limited to a planar shape, and may have a perturbation portion protruding in a three-dimensional shape. For example, the end portion of the ground conductor 13 may be raised and the above-described perturbation portion may be formed on the side surface of the dielectric substrate 12. Furthermore, it can also be set as a perturbation part by attaching another conductor.

  As described above, the various variations of the circularly polarized microstrip antenna enumerated in FIGS. 10 to 17 are merely examples. Actually, various forms of perturbations are applied to the patch conductor 11, the dielectric substrate 12, and the ground conductor 13. The present invention can be applied by combining the portions.

  Further, although the above embodiment relates to capacitive power feeding as an example, the power feeding method is not limited to this, and the present invention is also applied to various power feeding methods such as pin power feeding, microstrip line power feeding, and electromagnetic coupling power feeding. Can be applied.

  Note that the circularly polarized microstrip antenna according to the present embodiment is not limited to being used as an antenna corresponding to one frequency band, and can be incorporated into a multi-frequency shared antenna corresponding to a plurality of different frequency bands.

  FIG. 18 shows an example of a multi-frequency shared antenna to which the circularly polarized antenna according to the present invention is applied. The antenna of FIG. 18 has a structure in which the patch conductor 11 corresponding to the second frequency is cut out in the patch conductor 11 corresponding to the first frequency, and the two patch conductors are connected by the short-circuit portions 31a and 31b. It has become. Further, circularly polarized waves are radiated by the patch conductor 11, and the perturbation portions 11a and 11b are further provided to prevent the deterioration of the axial ratio due to the cross polarization component.

It is a figure which shows the structure of the circularly polarized microstrip antenna of this embodiment. Corresponding to the configuration of FIG. 1, a conventional circularly polarized microstrip antenna including a square patch conductor without a perturbation part and a first feeding part and a second feeding part is shown. It is a figure which shows the phase characteristic of the conventional circularly polarized microstrip antenna. It is the figure which showed polarization | polarized-light (phi) 1 and (phi) 2 as two orthogonal modes about the circularly polarized microstrip antenna of this embodiment. In the circularly polarized microstrip antenna of this embodiment, the phase characteristics of the input signal in the A direction and the polarizations φ1 and φ2 are fed only from the first feeding unit and not fed from the second feeding unit. FIG. When the circularly polarized microstrip antenna of the present embodiment is fed from the first feeding unit, the phase characteristics and the cross polarization gain of the circularly polarized wave are compared according to the presence or absence of the second feeding unit and the presence or absence of the perturbation unit. FIG. It is an axial ratio characteristic at the time of performing 2 point | piece power feeding with respect to the circularly polarized microstrip antenna of this embodiment. It is a figure which shows the state by which the patch conductor and the dielectric substrate were arrange | positioned asymmetrically with respect to the ground conductor. It is a figure which shows the axial ratio characteristic at the time of optimizing a perturbation part in the state which arranged the circularly polarized microstrip antenna of this embodiment asymmetrically like FIG. It is a figure which shows the variation of the circularly polarized microstrip antenna using a square patch conductor. It is a figure which shows the variation of the circularly polarized microstrip antenna at the time of making a patch conductor circular. It is a figure which shows the variation of a circularly polarized microstrip antenna at the time of providing a perturbation part only in one place using a square patch conductor. It is a figure which shows the variation of a circularly polarized microstrip antenna when it has the same symmetric structure as FIG. 12, and a patch conductor is circular. It is a figure which shows the variation of the circularly polarized microstrip antenna in the case of forming a patch conductor with an asymmetrical shape so that a patch conductor itself may have a perturbation structure. 10 shows a variation of the circularly polarized microstrip antenna when the patch conductor itself has a shape that is non-axisymmetric with respect to the A direction and the B direction, and a patch conductor is formed by combining the perturbation portions of FIGS. It is a figure which shows the variation of the circularly polarized microstrip antenna comprised by providing a perturbation part in the dielectric substrate. It is a figure which shows the variation of the circularly polarized microstrip antenna comprised by providing a perturbation part in a grounding conductor. It is a figure which shows an example of the multi-frequency common antenna which integrated the circularly polarized antenna to which this invention was applied, and the antenna corresponding to another frequency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Conductor patch 12 ... Dielectric substrate 13 ... Grounding conductor 14 ... 1st electric power feeding part 15 ... 2nd electric power feeding part

Claims (8)

A circularly polarized microstrip antenna capable of exciting circularly polarized waves,
A dielectric substrate having a predetermined thickness of dielectric material;
A patch conductor disposed on one surface of the dielectric substrate;
A ground conductor disposed on the other surface of the dielectric substrate;
A first power feeding section that is disposed in a first direction as viewed from the center of the patch conductor and feeds power to the patch conductor;
A second power supply that is arranged in a second direction orthogonal to the first direction when viewed from the center of the patch conductor and supplies power to the patch conductor with substantially the same amplitude and a phase that is approximately 90 ° different from the first power supply unit. And
A perturbation unit that is formed on any one of the patch conductor, the ground conductor, and the dielectric substrate, and adjusts the amount of degenerate separation of excitation by the first and second power feeding units;
A circularly polarized microstrip antenna comprising: The perturbation unit has a non-symmetrical structure with respect to at least one of two straight lines extending in the first direction and the second direction when viewed from the center of the patch conductor. Item 2. The circularly polarized microstrip antenna according to item 1. The perturbation unit calculates a phase difference between a first polarization excited in a direction that forms an angle of approximately 45 ° with each of the two straight lines, and a second polarization orthogonal to the first polarization. The circularly polarized microstrip antenna according to claim 2, which can be changed. The perturbation portion is formed at two positions along one of the first polarization and the second polarization and facing each other across the center of the patch conductor. Item 4. The circularly polarized microstrip antenna according to item 3. The perturbation section is formed at one position on a straight line that is parallel to either the first polarization or the second polarization and passes through the center of the patch conductor. 3. A circularly polarized microstrip antenna according to item 3. The said perturbation part is a notch area | region or protrusion area | region formed in the predetermined position of either the said patch conductor, the said ground conductor, and the said dielectric substrate, The one of Claim 1 to 5 characterized by the above-mentioned. A circularly polarized microstrip antenna as described in 1. The circularly polarized microstrip antenna according to any one of claims 1 to 5, wherein the perturbation part is a slot having a predetermined shape formed substantially at the center of the patch conductor or the ground conductor. A multi-frequency antenna capable of transmitting and receiving a plurality of frequencies and capable of transmitting and receiving circularly polarized waves at at least one of the plurality of frequencies,
A multi-frequency shared antenna, wherein the circularly polarized microstrip antenna according to any one of claims 1 to 7 is used for transmission / reception of at least one of frequencies transmitted / received by circular polarization.

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