Circular polarized wave microstrip antenna and multifrequency shared antenna

The present invention relates to a circularly polarized microstrip antenna capable of exciting circularly polarized waves, and in particular, by controlling the influence of a cross-polarized component generated in a two-point feeding type circularly polarized plane antenna, a good circular bias is obtained. The present invention relates to a circularly polarized microstrip antenna capable of maintaining wave antenna characteristics.

Conventionally, a two-point feeding 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 patch conductor as a radiating element and a feeding means including a feeding circuit for feeding the patch conductor. Then, the patch conductor is provided with two feeding parts arranged in two directions orthogonal to each other when viewed from the center of the patch, and the amplitude ratio of each feeding part is about 1: 1 and the phase difference between the two is about 90 °. Power is supplied so that As a result, polarized waves having the same amplitude and having a phase difference of 90 ° and orthogonal to each other are excited by the patch conductor, so that circularly polarized waves can be driven.<patcit num="1"><text>JP 2001-267835</text></patcit><patcit num="2"><text>Japanese Patent Application Laid-Open No. 2003-224416</text></patcit>

<p> In the above-mentioned conventional two-point feeding type circularly polarized microstrip antenna, there is a problem that the cross-polarized component increases due to the mutual coupling of the two feeding portions. Due to the influence of the cross-polarized wave component, the axial ratio is deteriorated, which hinders the maintenance of good characteristics of circularly polarized waves. On the other hand, in the above-mentioned conventional configuration, a method for suppressing the influence of the cross-polarized wave component has been proposed. For example, Patent Document 1 discloses a method of reducing the cross-polarized light component by shifting the amplitude ratio of the signals input to the two feeding units from 1: 1 or shifting the phase difference from 90 °. Further, Patent Document 2 discloses a method of setting the two feeding portions at positions shifted from the direction orthogonal to the patch center. By each of these methods, the above-mentioned cross-polarized wave component can be suppressed.</p><p> However, the methods disclosed in the above-mentioned Patent Documents 1 and 2 all relate to the feeding means such as the structure of the feeding portion and the configuration of the feeding circuit. Therefore, when such a method is applied, the design load of the feeding means becomes large, and there is a problem that the characteristics of circularly polarized waves cannot be easily optimized.</p><p> Further, when a circularly polarized microstrip antenna is incorporated into an apparatus, the characteristics of circularly polarized waves may be adversely affected by the surrounding environment such as a circuit board, other functional components, and cables. It is not easy to optimize the characteristics of circularly polarized waves suitable for the surrounding environment such as these by the feeding means.</p><p> Therefore, the present invention has been made to solve these problems, and when a two-point feeding method is adopted in a circularly polarized microstrip antenna, the cross-polarized component due to the mutual coupling of the two feeding parts is present. It is an object of the present invention to provide a circularly polarized microstrip antenna which can control the influence and has good circularly polarized characteristics by performing appropriate control even under the influence of the surrounding environment. .. </p>

<p> In order to solve the above problems, the circularly polarized microstrip antenna according to claim 1 is a circularly polarized microstrip antenna capable of exciting circularly polarized waves, and is a dielectric material formed of a dielectric material having a predetermined thickness. The body substrate, the patch conductor arranged on one surface of the dielectric substrate, the ground conductor arranged on the other surface of the dielectric substrate, and arranged in the first direction when viewed from the center of the patch conductor. The first feeding portion that feeds the patch conductor and the first feeding portion that feeds the patch conductor are arranged in a second direction that is orthogonal to the first direction when viewed from the center of the patch conductor, and have substantially the same amplitude and substantially the same amplitude as the first feeding portion. A second feeding portion that feeds the patch conductor in 90 ° different phases, and the patch conductor, the ground conductor, or the dielectric substrate are formed, and the amount of excitation withdrawal and separation by the first and second feeding portions. It is characterized in that it is provided with a perturbation unit for adjusting.</p><p> According to the present invention, when two-point power feeding is performed on the circularly polarized microstrip antenna and power is supplied from the first feeding unit and the second feeding unit so that the phases are approximately 90 ° with substantially the same amplitude, a patch is applied. The conductor can be driven by circularly polarized waves. At this time, in the excitation in two directions connecting each feeding part from the center of the patch, a cross-polarized light component is generated due to the presence of the two feeding parts, but the degenerate separation amount should be adjusted appropriately by changing the state of the perturbing part. For example, the generated cross-polarized light component can be controlled. Therefore, it is possible to accurately prevent deterioration of the axial ratio and the like due to an increase in the cross-polarized wave component, and to maintain good circularly polarized wave characteristics. In addition, the characteristics of circularly polarized waves can be kept good by adjusting the amount of degenerate separation that is suitable even under the influence of the surrounding environment. This characteristic improvement method does not impose a load on the power supply circuit or the like to change the design, and adjusts only the antenna portion, thereby realizing simplification of the design.</p><p> In the invention of claim 1, the circularly polarized microstrip antenna according to claim 2 has the perturbation portion extending in the first direction and the second direction when viewed from the center of the patch conductor. It is characterized by having a structure that is non-axisymmetric with respect to at least one of the straight lines.</p><p> According to the present invention, in addition to the action of the above-mentioned invention, the perturbation part has a non-axisymmetric structure with respect to the two directions in which the two feeding parts are viewed from the center of the patch. The amount of degeneracy separation can be freely adjusted.</p><p> The circularly polarized microstrip antenna according to claim 3 is the first polarized wave according to the invention according to claim 2, wherein the perforating portion excites in a direction forming an angle of approximately 45 ° with each of the two straight lines. It is characterized in that it is possible to change the phase difference between the first polarized light and the second polarized light orthogonal to the first polarized light.</p><p> According to the present invention, in addition to the effects of the above invention, when two polarized waves forming an angle of 45 ° with respect to the two directions of viewing the two feeding parts from the center of the patch are assumed, for example, those polarizations. By providing a perturbation unit capable of imparting a predetermined difference to the electrical lengths of the above, it is possible to easily design the adjustment of their phase differences, that is, the adjustment of the degenerate separation amount. As a result, the characteristics of circularly polarized waves can be easily and surely improved.</p><p> In the invention of claim 3, the circularly polarized microstrip antenna according to claim 4 has the perturbation portion along the direction of either the first polarization or the second polarization. It is characterized in that it is formed at two positions facing each other across the center of the patch conductor.</p><p> Further, in the circularly polarized microstrip antenna according to claim 5, in the invention according to claim 3, the perturbation portion is parallel to either the first polarized light or the second polarized light. It is characterized in that it is formed at one position on a straight line passing through the center of the patch conductor.</p><p> Further, in the circularly polarized microstrip antenna according to claim 6, in the invention according to any one of claims 1 to 5, the perturbation portion is any one of the patch conductor, the ground conductor, and the dielectric substrate. It is characterized in that it is a notched region or a protruding region formed at a predetermined position on the outer shape of.</p><p> Further, in the circularly polarized microstrip antenna according to claim 7, in the invention according to any one of claims 1 to 5, the perturbation portion is formed at substantially the center of the patch conductor or the ground conductor. It is characterized by being a slot having a shape.</p><p> According to the inventions described in claims 4 to 7, there are various variations in the position, shape, number, etc. of the perturbation parts applicable to the patch conductor, the ground conductor, and the dielectric substrate, and the antenna shape. The most suitable perturbation part can be selected and adopted according to the device configuration.</p><p> The invention according to claim 8 is a multi-frequency shared antenna capable of transmitting and receiving a plurality of frequencies and transmitting and receiving circularly polarized waves at at least one of the plurality of frequencies. The multi-frequency shared antenna according to any one of claims 1 to 7, wherein the circularly polarized microstrip antenna according to any one of claims 1 to 7 is used for transmitting and receiving at least one of the frequencies transmitted and received in.</p><p> According to the present invention, even in a multi-frequency shared antenna corresponding to multi-frequency transmission / reception, the circularly polarized wave characteristics can be kept good by using the antenna to which the present invention is applied to the transmission / reception of circularly polarized waves.</p>

<p> According to the present invention, the circularly polarized microstrip antenna that feeds at two points is provided with a perturbation section for adjusting the degenerate separation amount of the circularly polarized wave, so that each feeding section is provided from the center of the patch. In the excitation in the two directions to connect, the cross-polarized light component generated by the presence of the two feeding parts can be suppressed by adjusting the degenerate separation amount by the perturbing part. Therefore, it is possible to accurately prevent deterioration of the axial ratio and the like due to an increase in the cross-polarized wave component, and to maintain good circularly polarized wave characteristics. In addition, the characteristics of circularly polarized waves can be kept good by adjusting the amount of degenerate separation against the influence of the surrounding environment.</p>

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the structure of the circularly polarized microstrip antenna of the present 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 arranged on the upper surface of the dielectric substrate 12. Here, the case where the shape of the patch conductor 11 is square is shown, but a 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, has an outer shape larger than that of the patch conductor 11, and is formed to a predetermined thickness. Further, as shown in the side view of FIG. 1, a ground conductor 13 having a predetermined shape is arranged 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 in between. It is arranged.

A first power supply unit 14 and a second power supply unit 15 for supplying power to the patch conductor 11 are provided on the upper flat surface of the dielectric substrate 12. These first feeding unit 14 and second feeding unit 15 are configured to supply power to the patch conductor 11 by capacitive coupling, and the first feeding line 14a and the second feeding line penetrating the dielectric substrate 12, respectively. It is connected to the power supply circuit via 15a.

As shown in FIG. 1, when viewed from the patch center C of the patch conductor 11, the first feeding point F1 set at substantially the center of the first feeding portion 14 is arranged on a straight line in the direction of arrow A, and the second feeding point F1 is arranged. The feeding point F2 set in the substantially center of the feeding unit 15 is arranged on a straight line in the direction of arrow B. The straight line in the A direction and the straight line in the B direction with the patch center C as the base point are orthogonal to each other. In such an arrangement, the circularly polarized microstrip antenna is driven by circularly polarized waves by inputting signals having the same amplitude but different phases by 90 ° to the first feeding unit 14 and the second feeding unit 15. Is possible.

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

In FIG. 1, when the patch conductor 11 is generally excited without providing the perturbation portions 11a and 11b, cross-polarization occurs due to the positional relationship between the first feeding portion 14 and the second feeding portion 15, which causes the axis. There is a risk of degrading circularly polarized antenna characteristics such as ratio. On the other hand, in the present embodiment, by forming the perturbation portions 11a and 11b at the two locations of the patch conductor 11 as described above, deterioration of the antenna characteristics due to the influence of the cross-polarized light component, which is a problem in the two-point feeding method, can be prevented. I'm trying.

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

First, as shown in FIG. 2 (a), consider a case where a square patch conductor 21 having no general perturbation section is fed from the first feeding section 22. At this time, the excitation by the first feeding unit 22 can be considered as a superposition of two orthogonal modes, the polarized wave φ1 and the polarized wave φ2, as shown in FIG. 2 (a). The excitation directions of these polarized waves φ1 and φ2 shall be at 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 the second feeding unit does not exist (one-point feeding), the respective polarizations φ1 and φ2 have the same amplitude and phase when observed in the respective φ1 and φ2 directions, so that the patch conductor The resonance component of 21 is purely composed of the component in the A direction, and the component in the B direction is not generated. In such a state, the frequency characteristics of the radiation phase in the antenna zenith direction for the polarized waves φ1 and φ2 are shown in FIG. 3 (a). The antenna characteristics shown below are all in the antenna zenith direction. In FIG. 3 (a), it can be seen that the phases of the polarized waves φ1 and φ2 are almost the same. That is, in the case of one-point feeding from the first feeding unit 22, the problem caused by cross-polarization does not occur.

On the other hand, as shown in FIG. 2B, when there is a second feeding unit 23 that does not supply power, a frequency difference or a phase difference occurs between the modes of polarization φ1 and φ2. The phase characteristics corresponding to FIG. 3 (a) in this case are shown in FIG. 3 (b). In FIG. 3 (b), unlike FIG. 3 (a), it can be seen that the phases of the polarized waves φ1 and φ2 are out of phase. This is a state in which the polarized waves φ1 and φ2 are degenerately separated unintentionally because the positions of the first feeding unit 22 and the second feeding unit 23 are asymmetric with respect to the polarized waves φ1 and φ2. Is.

Therefore, when power is supplied from one of the first power supply units 22 in the two-point power supply configuration, the excitation component is a weak intersection in which the phase difference is approximately 90 ° in the B direction in addition to the main polarization component in the A direction. Polarized components appear. Here, considering the case where power is supplied only from the second power feeding unit 23, in addition to the main polarization component in the B direction from the same phenomenon as described above, a weak crossing bias in which the phase difference is approximately 90 ° in the A direction. Wave components appear. Then, in the case of two-point feeding with a phase difference of 90 ° to the first feeding section 22 and the second feeding section 23 in FIG. 2B, that is, circularly polarized drive, the main polarization is achieved in each of the directions A and B. One of the components and the cross-polarized component can strengthen each other, and the other can weaken each other. Therefore, under such a situation, a difference occurs in the antenna gains in the A direction and the B direction, and the axial ratio of the circularly polarized microstrip antenna deteriorates.

On the other hand, in the circularly polarized microstrip antenna of the present embodiment, the deterioration of the axial ratio is prevented by intentionally controlling the unintentional degenerate separation state that causes the above phenomenon. FIG. 4 shows a case where the circularly polarized microstrip antenna of the present embodiment is fed only from 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 in which the perturbation portions 11a and 11b are formed, and the other polarization φ2 is the perturbation portion 11a. , 11b is not formed diagonally.

With such an arrangement, the perturbation units 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 the phase difference of the polarized waves φ1 and φ2 can be changed. That is, in FIG. 4, when the adjustment amount according to the shape and size of the perturbation portions 11a and 11b is appropriately set for the polarized waves φ1 and φ2, the degeneracy separation can be suppressed and the intersections appearing in the A direction and the B direction. The polarization component can be reduced to optimize the characteristics of circularly polarized waves such as the axial ratio.

FIG. 5 is a diagram showing phase characteristics for polarized waves φ1 and φ2 by feeding power only from the first feeding unit 14 with the perturbation units 11a and 11b appropriately adjusted in FIG. 3 (b). ) Is a characteristic based on the same conditions. It can be seen that the phase shift as seen in FIG. 3 (b) does not occur between the modes of polarization φ1 and φ2. That is, FIG. 5 shows that it is actually possible to eliminate the phase difference by adding the perturbation parts 11a and 11b, that is, to suppress the 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 (Fig. 2 (a), Fig. 3 (a)), and (B) has a second power supply unit. (Fig. 2 (b), Fig. 3 (b)), and (C) are the cases where the second feeding part exists and the perturbation part is provided (Figs. 4 and 5). In each state, the phase difference representing the degenerate separation amount of the polarized waves φ1 and φ2 described above and the gain of the cross-polarized light component generated due to the phase difference are plotted. In (B), which is a general arrangement of two-point fed circularly polarized microstrip antennas, a cross-polarized component is generated because they are in a degenerate and separated state due to the presence of two feeding portions. On the other hand, the arrangement (C) of the two-point fed circularly polarized microstrip antenna having the perturbation portion of the present embodiment has succeeded in suppressing the degenerate separation and reducing the cross-polarized component. As a result, it is possible to prevent deterioration of circularly polarized wave characteristics such as the axial ratio in the present embodiment as compared with the case without a general perturbation part.

Next, FIG. 7 is a diagram showing the frequency characteristics of the axial ratio when the two-point feeding circularly polarized light drive is completely isolated from the circularly polarized microstrip antenna of the present embodiment. Note that FIG. 7 (a) shows the characteristics when the perturbation parts 14 and 15 of this embodiment are provided (Fig. 4), and FIG. 7 (b) shows a configuration without a general perturbation part for comparison. The characteristics in the case of (Fig. 2 (b)) are shown.

Comparing the characteristics of FIGS. 7 (a) and 7 (b), it can be seen that the axial ratio can be generally suppressed to a small value by the configuration of the present embodiment. This is because there is almost no difference in the gain of polarization in the A and B directions in FIG. 7 (a) with respect to the difference in the gain of polarization in the A and B directions in FIG. 7 (b). There is. In the present embodiment, the cross polarization component can be reduced by the action of the perturbation portions 11a and 11b as described above, whereby the difference in the gain of polarization in the A direction and the B direction can be reduced and the axial ratio can be brought close to zero. .. Therefore, it is advantageous to adopt the configuration of the present embodiment in order to improve the characteristics of circularly polarized waves at the time of feeding at two points.

Next, it will be described that the circularly polarized microstrip antenna of the present embodiment is also useful when mounted on a wireless device or the like. In general, when an antenna is incorporated inside a device such as a wireless device, there may be a cable or other functional component in the circuit board or its surroundings, and the antenna may be arranged close to the antenna. There is a problem that the antenna characteristics deteriorate due to the influence of the surrounding environment when the antenna is incorporated. In response to such a problem, in the circularly polarized microstrip antenna of the present embodiment, the deterioration of characteristics due to the influence of the surrounding environment can be improved by adjusting the perturbation portions 11a and 11b as described below.

As an example in which the influence of the surrounding environment becomes a problem, the case where the circularly polarized microstrip antennas are asymmetrically arranged on the 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 surface of the circuit board. That is, ideally, when the patch conductor 11 and the dielectric substrate 12 are arranged substantially in 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. Is kept in. On the other hand, when the antenna is arranged asymmetrically as shown in FIG. 8, the influence of the surroundings differs depending on the direction, which causes deterioration of the antenna characteristics.

In the present embodiment, the antenna characteristics can be optimized by adjusting the perturbation portions 11a and 11b even when the antennas are arranged asymmetrically as shown in FIG. In the case of the 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 circularly polarized light. Therefore, in order to eliminate the difference in gain caused by the asymmetry of the surroundings, the shapes of the perturbation portions 11a and 11b may be appropriately set to optimize the degenerate separation amount and improve the characteristics of circularly polarized light.

Fig. 9 (a) shows the axial ratio characteristics in the antenna zenith direction when the perturbation units 11a and 11b are optimized with the circularly polarized microstrip antenna of this embodiment asymmetrically arranged as shown in FIG. For comparison with FIG. 9 (a), FIG. 9 (b) shows the characteristics when the perturbation portions 11a and 11b are not provided and are arranged asymmetrically as shown in FIG. 8 in the configuration of FIG. In the general configuration in which the perturbation portions 11a and 11b shown in FIG. 9B are not provided, the axial ratio is considerably deteriorated, whereas in the configuration of the present embodiment shown in FIG. 9A, the shaft is used. The ratio is kept small enough. Incidentally, the shapes of the perturbation portions 11a and 11b in FIG. 8 are different in the size of the notch as compared with the shapes in FIG. This is not the symmetrical arrangement, but the method for reducing the cross-polarization component in FIG. 4 in order to eliminate the gain difference newly generated by the asymmetrical arrangement, and here the amount of the cross-polarization component is intentionally suitable. It is said that it was used to adjust the gain difference and control the gain difference. As described above, the circularly polarized microstrip antenna of the present embodiment is excellent in that the characteristics of circularly polarized waves can be optimized so as to be suitable for the surrounding environment such as mounting on a circuit board.

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

FIG. 10 is a diagram showing variations of a circularly polarized microstrip antenna using a square patch conductor 11. The three structures in Fig. 10 (a), (b), and (c) are all non-axisymmetric with respect to the A and B directions in Fig. 1, but are rotated by 45 ° from the A and B directions. This is an example of the case where the line is symmetric with respect to the two directions. First, FIG. 10 (a) gives an example having the same structure as that of FIG. FIG. 10B shows a structure having square perturbation portions 11c and 11d formed so as to project from two opposite corners of the square of the patch conductor 11. FIG. 10 (c) shows a structure in which one rectangular slot is formed in the central portion of the patch conductor 11 and this slot is used as the perturbation portion 11d.

FIG. 11 is a diagram showing variations of a circularly polarized microstrip antenna when the patch conductor 11 is circular instead of square. The three structures of FIGS. 11 (a), (b), and (c) are non-axisymmetric with respect to the A and B directions of FIG. 1 as in FIG. 10, but 45 from the A and B directions. It becomes line symmetric with respect to the two directions rotated by °. FIG. 11 (a) shows a structure having perturbation portions 11e and 11f having the same shape as the perturbation portions 11a and 11b of FIG. 10 (a), and FIG. 11 (b) shows the perturbation portions of FIG. 10 (b). A structure having perturbation parts 11g and 11h having the same shape as 11c and 11d is shown, and FIG. 11 (c) shows a structure having a perturbation part 11i having the same shape as the perturbation part 11d of FIG. 10 (c).

FIG. 12 is a diagram showing a variation of a circularly polarized microstrip antenna when a square patch conductor 11 is used and a perturbation portion is provided at only one place. In the structure of FIG. 12, it is non-axisymmetric with respect to the A and B directions, and is line-symmetric with respect to one of the two directions rotated by 45 ° from the A-direction and B-direction, and non-line-symmetric with respect to the other. FIG. 12A shows a structure having one perturbation portion 11j cut out from a square region at one corner of the patch conductor 11. FIG. 12 (b) shows a structure having one perturbation portion 11k formed from one corner of the patch conductor 11 to the same shape as the perturbation portions 11c and 11d of FIG. 10 (b).

FIG. 13 is a diagram showing variations of a circularly polarized microstrip antenna when the patch conductor 11 has a circular structure instead of a square while having a symmetrical structure similar to that of FIG. FIG. 13 (a) shows a structure having one perturbation portion 11l in which a predetermined region at one end of the patch conductor 11 is cut out. FIG. 13 (b) shows a structure having one perturbation portion 11m having the same shape as the perturbation portion 11k in FIG. 12 (b).

FIG. 14 shows a variation of the circularly polarized microstrip antenna when the patch conductor 11 is formed in an asymmetrical shape instead of a symmetrical 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 and B directions, and are axisymmetric with respect to the two directions rotated by 45 ° from the A and B directions. FIG. 14 (a) shows a structure in which the shape of the patch conductor 11 is a parallelogram, and FIG. 14 (b) shows a structure in which the shape of the patch conductor 11 is an ellipse.

In FIG. 15, 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 set to, for example, a rectangular shape, and the above-mentioned moving part is used. A variation of the circularly polarized microstrip antenna when forming the combined patch conductor 11 is shown. In the structure of FIG. 15, it is asymmetric with respect to the A direction and the B direction. FIG. 15 (a) shows a structure in which the rectangular patch conductor 11 has the perturbation portions 11a and 11o having the same shape as the perturbation portions 11a and 11b of FIG. 10 (a), and FIG. 15 (b) 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. 12 (a).

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

In FIG. 16 (a), perturbation portions 12a and 12b are provided at two opposite corners of the square dielectric substrate 12, and in FIG. 16 (b), perturbation portions 12c are provided at one corner of the square dielectric substrate 12. In FIG. 16 (c), perturbation portions 12d and 12e projecting from two opposing positions of the circular dielectric substrate 12 are provided. As described above, when the perturbation portion is provided on the dielectric substrate 12, basically the same forming method as the case where the perturbation portion is provided on the patch conductor 11 can be applied.

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

In FIG. 17 (a), a perturbation portion 13a is provided at one corner of the square ground conductor 13, and in FIG. 17 (b), a perturbation portion 13b consisting of a rectangular slot is provided in the center of the square ground conductor 13. .. As described above, when the ground conductor 13 is provided with the perturbation portion, the same forming method as in the case where the patch conductor 11 is provided with the perturbation portion can be applied.

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

As described above, the various variations of the circularly polarized microstrip antennas listed in FIGS. 10 to 17 are merely examples, and in reality, various forms of perturbation are applied to the patch conductor 11, the dielectric substrate 12, and the ground conductor 13. The present invention can be applied by forming the portions in combination.

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

The circularly polarized microstrip antenna according to the present embodiment is not limited to the case where it is used as an antenna corresponding to one frequency band, and can be used by being 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 a patch conductor 11 corresponding to the first frequency is hollowed out, a patch conductor 31 corresponding to the second frequency is arranged therein, and the two patch conductors are connected by short-circuited portions 31a and 31b. It has become. Circularly polarized waves are radiated by the patch conductor 11, and perturbation portions 11a and 11b are further provided to prevent deterioration of the axial ratio due to the cross-polarized light component.

<figref num="1">It is a figure which shows the structure of the circularly polarized microstrip antenna of this embodiment.</figref><figref num="2">Corresponding to the configuration of FIG. 1, a square patch conductor without a perturbation section and a conventional circularly polarized microstrip antenna including a first feeding section and a second feeding section are shown.</figref><figref num="3">It is a figure which shows the phase characteristic of the conventional circularly polarized microstrip antenna.</figref><figref num="4">It is a figure which showed the polarized wave φ1 and φ2 as two orthogonal modes about the circularly polarized wave microstrip antenna of this embodiment.</figref><figref num="5">Regarding the circularly polarized microstrip antenna of the present embodiment, in a state where power is supplied only from the first feeding unit and no power is supplied from the second feeding unit, the input signal in the A direction and the phase characteristics of the polarized waves φ1 and φ2. It is a figure which shows.</figref><figref num="6">When power is supplied to the circularly polarized microstrip antenna of the present embodiment from the first feeding unit, the phase characteristics of circularly polarized waves and the cross-polarized gain are compared according to the presence or absence of the second feeding unit and the presence or absence of the perturbing unit. It is a figure which shows.</figref><figref num="7">The axial ratio characteristic when the circularly polarized microstrip antenna of the present embodiment is fed at two points is shown.</figref><figref num="8">It is a figure which shows the state which the patch conductor and the dielectric substrate are asymmetrically arranged with respect to the ground conductor.</figref><figref num="9">It is a figure which shows the axial ratio characteristic at the time of optimizing the perturbation part with the circularly polarized microstrip antenna of this embodiment asymmetrically arranged as shown in FIG.</figref><figref num="10">It is a figure which shows the variation of the circularly polarized microstrip antenna using the square patch conductor.</figref><figref num="11">It is a figure which shows the variation of the circularly polarized microstrip antenna when the patch conductor is circular.</figref><figref num="12">It is a figure which shows the variation of the circularly polarized microstrip antenna when the perturbation part is provided only at one place using the square patch conductor.</figref><figref num="13">It is a figure which has the same symmetric structure as FIG. 12, and shows the variation of the circularly polarized microstrip antenna when the patch conductor is circular.</figref><figref num="14">It is a figure which shows the variation of the circularly polarized microstrip antenna when the patch conductor is formed in an asymmetrical shape in order to give a perturbation structure to the patch conductor itself.</figref><figref num="15">The variation of the circularly polarized microstrip antenna when the shape of the patch conductor itself is non-axisymmetric with respect to the A direction and the B direction to form a patch conductor in which the perturbation parts of FIGS. 10 and 12 are combined is shown.</figref><figref num="16">It is a figure which shows the variation of the circularly polarized microstrip antenna which was formed by providing the perturbation part on the dielectric substrate.</figref><figref num="17">It is a figure which shows the variation of the circularly polarized microstrip antenna which was formed by providing the perturbation part in the ground conductor.</figref><figref num="18">It is a figure which shows an example of the multi-frequency shared antenna which integrated the circularly polarized antenna to which this invention was applied, and the antenna corresponding to other frequencies.</figref>

Code description

11 ... Conductor patch 12 ... Dielectric substrate 13 ... Ground conductor 14 ... 1st power supply 15 ... 2nd power supply