JP4188975B2 - Phased array antenna for mobile satellite communications - Google Patents

Description

  The present invention relates to a phased array antenna for mobile satellite communication that is mounted on a mobile body such as a vehicle, a railcar, and an aircraft and that receives radio waves from a geostationary satellite.

  In the mobile satellite communication system, radio waves transmitted from geostationary satellites are linearly polarized waves. The phased array antenna for mobile satellite communication used in this mobile satellite communication system scans the direction of the combined beam so as to track a geostationary satellite as the mobile body moves. Since the polarization direction of the combined beam deviates from the zenith, the tilt of the polarization plane of the combined beam changes, and the linear polarization direction of the radio wave from the geostationary satellite and the phase shift for mobile satellite communication The tilt of the polarization plane of the combined beam of the array antenna does not match, and the reception level decreases.

  In the prior art, Japanese Patent Application Laid-Open No. 2002-141849, a polarization plane control unit is connected to an active phased array antenna of a mobile satellite communication device, and this polarization plane control unit responds to changes in the scanning angle of the combined beam. The one that controls the tilt of the polarization plane of the combined beam to match the direction of linear polarization of radio waves from geostationary satellites has been proposed.

JP 2002-141849 A

  However, in the case where the polarization plane control unit is provided as in the prior art, the scale of the antenna system including the phased array antenna for mobile satellite communication becomes large, and this antenna system becomes expensive.

  The present invention proposes an improved phased array antenna for mobile satellite communication which can improve the reduction of the reception level with a simple structure without providing a polarization plane control section.

  A phased array antenna for mobile satellite communication according to a first aspect of the present invention is a phased array antenna for mobile satellite communication that is mounted on a mobile body and receives radio waves from a geostationary satellite, and includes a dielectric substrate and the dielectric substrate. When assuming three-axis coordinates of the X axis, the Y axis, and the Z axis so that the main surface of the body substrate is located on the XY plane, the main surface of the dielectric substrate is aligned along the X axis on the main surface of the dielectric substrate A plurality of antenna element patches arranged, a feed line arranged on the main surface of the dielectric substrate, connected to each antenna element patch, and arranged on the feed line, each of the antenna element patches A plurality of phase shifters connected to each other, the plurality of phase shifters between the first scanning angle and the second scanning angle in the XZ plane of the three-axis coordinates. Scan the combined beam Further, the cross polarization component with respect to the change in the scan angle of the combined beam has a minimum value between the first scan angle and the second scan angle, and increases on both sides of the minimum value. In addition, each antenna element patch has a patch center connecting the center point and the feed point so that the antenna element patch has a U-shaped characteristic that is less than or equal to a required standard level at the first and second scanning angles. The line is arranged with a predetermined inclination angle with respect to the X-axis.

  A phased array antenna for mobile satellite communication according to a second aspect of the present invention is a phased array antenna for mobile satellite communication that is mounted on a mobile body and receives radio waves from a stationary satellite, and includes a dielectric substrate, When the three-axis coordinates of the X axis, the Y axis, and the Z axis are assumed so that the principal surface of the dielectric substrate is located on the XY plane, the dielectric substrate is arranged along the X axis on the principal surface of the dielectric substrate. A plurality of antenna element patches, a feed line arranged on the main surface of the dielectric substrate, and a plurality of phase shifters arranged on the feed line, the feed lines, A two-branch line is provided between the phase shifter and the antenna element patch, and the two-branch line has two feeding points at different locations on the same antenna element patch. The center point of the antenna element patch and each of the feeding points Two straight lines connecting The plurality of phase shifters scan the combined beam of each antenna element patch between the first scanning angle and the second scanning angle in the XZ plane of the three-axis coordinates. In addition, the cross polarization component with respect to the change in the scan angle of the combined beam has a minimum value between the first scan angle and the second scan angle, and both sides of the minimum value. In addition, the distribution ratio of the two-branch lines and the length of the two-branched lines are such that the U-shaped characteristic is less than the required specified level at the first and second scanning angles. It is characterized by being given.

  In the phased array antenna for mobile satellite communication according to the first aspect of the present invention, the plurality of phase shifters are arranged between the first scanning angle and the second scanning angle in the XZ plane of the three-axis coordinates. It is configured to scan the combined beam of the antenna element patch, and the cross polarization component with respect to the change in the scanning angle of the combined beam becomes the minimum value between the first scanning angle and the second scanning angle. Each antenna element patch has its center point so that it has a U-shaped characteristic that increases on both sides of this minimum value and is below the required standard level at the first and second scanning angles. Since the patch center line connecting to the feeding point is arranged at a predetermined inclination angle with respect to the X axis, it is possible to improve the reduction in reception level with a simple structure without providing a polarization plane control unit. it can.

  In the phased array antenna for mobile satellite communication according to the second aspect of the present invention, the cross polarization component with respect to the change in the scanning angle of the combined beam has a prescribed level required at the first and second scanning angles. The generation of cross-polarization can be reduced by giving the distribution ratio of the two-branch line so that it has the following U-shaped characteristics, and circular polarization can be achieved by giving the length of the two-branch line of the two-branch line The cross-polarization of the signal can be suppressed, the reception level is reduced with a simple configuration using only a planar circuit, and a high signal-to-interference ratio can be achieved even in the presence of interference signals with orthogonal polarization. Obtainable.

  Several embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a diagram showing Embodiment 1 of a phased array antenna for mobile satellite communication according to the present invention, FIG. 1 (a) is a perspective view thereof, and FIG. 1 (b) is a plan view of the antenna element patch. is there.

  The phased array antenna 10 for mobile satellite communication according to the first embodiment is mounted on a mobile body including vehicles such as automobiles, orbital vehicles such as trains, airplanes such as airplanes and helicopters, and receives radio waves from stationary satellites (not shown). To do. Radio waves from geostationary satellites have a Ku band frequency and a 12 GHz band frequency. Radio waves from this geostationary satellite are assumed to be linearly polarized waves. The phased array antenna 10 of the first embodiment is a one-dimensional phased array antenna, and a plurality of antenna element patches are arranged one-dimensionally along a common axis.

  A phased array antenna 10 for mobile satellite communication according to the first embodiment includes a dielectric substrate 1, an antenna element patch group 2, a feed line 3, a reception output terminal 4, and a phase shifter group 5.

  The dielectric substrate 1 is an insulating resin substrate such as Teflon (registered trademark), and has a main surface 1a. The main surface 1a is an upper main surface, and the lower main surface facing the main surface 1a is entirely covered with a ground conductor (not shown). This ground conductor is connected to ground potential.

  The antenna element patch group 2, the feed line 3, the reception output terminal 4, and the phase shifter group 5 are all arranged on the main surface 1 a of the dielectric substrate 1. The antenna element patch group 2 includes n antenna element patches 2 a, 2 b,..., 2 n, and each of these antenna element patches 2 a, 2 b,. It is formed by patterning the upper conductor layer. In FIG. 1, n = 4 and four antenna element patches 2a, 2b,..., 2n are illustrated, but in reality, a larger number of antenna element patches are arranged.

  The antenna element patches 2a, 2b,..., 2n all have the same size and shape, and in the first embodiment, for example, rectangular shapes having the same vertical dimension and the same horizontal dimension, specifically, Is formed in a rectangular shape. Each antenna element patch 2a, 2b,..., 2n has a center point C and a feeding point F, respectively. The center point C is an intersection of a pair of diagonal lines for each of the antenna element patches 2a, 2b, ..., 2n. The feeding point F is an intermediate point on one side of each of the antenna element patches 2a, 2b, ..., 2n.

  For the dielectric substrate 1, a three-axis coordinate 7 of X axis, Y axis, and Z axis orthogonal to each other is assumed. The three-axis coordinate 7 is shown on the left side of FIG. The triaxial coordinates 7 are assumed such that the main surface 1a of the dielectric substrate 1 is located on the XY plane defined by the X axis and the Y axis. The antenna element patches 2a, 2b,... 2n are arranged side by side at equal intervals along the X axis so that the center point C is located on the X axis of the triaxial coordinate 7. . The feeding point F is also formed so as to be located on the same side with respect to each of the antenna element patches 2a, 2b,.

A straight line connecting the center point C and the feeding point F will be referred to as a patch center line PC. The patch inclination angle φ with respect to the X axis of the patch center line PC is the same for each of the antenna element patches 2a, 2b,. In the first embodiment, the patch inclination angle φ is set to a predetermined inclination angle φ1. In other words, in the first embodiment, each of the antenna element patches 2a, 2b,..., 2n is arranged such that each patch center line PC is inclined by a predetermined inclination angle φ1 with respect to the X axis. .

  Feed line 3 is formed on main surface 1 a of dielectric substrate 1. The feed line 3 is also formed by patterning the conductive layer on the main surface 1 a of the dielectric substrate 1 together with the antenna element patch group 2. The feed line 3 is a line connecting the feed point F of each antenna element patch 2a, 2b,..., 2n and the reception output terminal 4, and includes a branch line 3a and a common line 3b. The branch line 3a branches from the common line 3b toward the feeding points F of the antenna element patches 2a, 2b,. The feed line 3 includes a plurality of bent portions 3c, and unnecessary radiation is generated in the bent portions 3c of the feed line 3.

  The phase shifter group 5 includes a plurality of n phase shifters 5a, 5b,..., 5n, the same number as the antenna element patches 2a, 2b,. Each of these phase shifters 5a, 5b,..., 5n is arranged on a branch line 3a corresponding to each antenna element patch 2a, 2b,. Each of these phase shifters 5a, 5b,..., 5n scans the beam of each antenna element patch 2a, 2b,. Scan the group 2 composite beam.

  In the first embodiment, as the moving body moves, the combined beam of the antenna element patch group 2 is scanned so as to track a geostationary satellite. In the first embodiment, the combined beam is scanned in the XZ plane, and in the XZ plane, corresponding to the movement of the moving body, between the first scanning angle θ1 and the second scanning angle θ2. Configured to be scanned.

  Now, the inclination of the polarization plane of the antenna element patch group 2 combined beam in the phased array antenna 10 for mobile satellite communication and the azimuth inclination of the linearly polarized wave of the radio wave from the geostationary satellite will be described with reference to FIG. FIG. 2 (a) shows the change in the inclination of the polarization plane of the combined beam of the antenna element patch group 2 in the phased array antenna 10 for mobile satellite communications of the first embodiment at the assumed three-axis coordinate 7. FIG. (B) shows the direction of linear polarization of radio waves from a geostationary satellite with respect to the same three-axis coordinate 7. The geostationary satellite is in the zenith direction, and the Z axis faces the zenith. The direction of the linearly polarized wave of the radio wave from the geostationary satellite is indicated by an arrow A in FIG. 2B, and is inclined by an angle φ0 with respect to the XZ plane. In FIG. 2B, the three-axis coordinates of the X axis, the Y axis, and the Z axis are shown as viewed from the zenith, and the Z axis is perpendicular to the paper surface. Specifically, the azimuth inclination angle φ0 of the linearly polarized wave of the radio wave from the geostationary satellite is 7 degrees. In the phased array antenna 10 for mobile satellite communication, when the combined beam of the antenna element patch group 2 is scanned in the Z-axis direction, the inclination of the polarization plane of the combined beam is indicated by an arrow A1 shown in FIG. In this way, it is assumed that the direction of the linearly polarized wave of the radio wave from the geostationary satellite indicated by the arrow A in FIG.

  The phased array antenna 10 for mobile satellite communication tracks a geostationary satellite as the mobile body moves, and the combined beam of the antenna element patch group 2 is in the XZ plane with the first scan angle θ1 and the second scan angle θ2. Scanning with the scanning angle θ2. The combined beam scanning angle increases from the Z-axis toward the X-axis, and the first and second scanning angles θ1 and θ2 have a relationship of θ1 <θ2. Specifically, the first scanning angle θ1 is set to 25 degrees, and the second scanning angle θ2 is set to 60 degrees. When the combined beam of the antenna element patch group 2 is scanned at the first scanning angle θ1, the direction of polarization of the combined beam with the XZ plane is smaller than that of the arrow A1, as indicated by an arrow A2. When the combined beam is scanned at the second scanning angle θ2, the angle of polarization of the combined beam with the XZ plane is smaller than that of the arrow A2, as indicated by an arrow A3. Tilt in the direction.

  In the phased array antenna 10 for mobile satellite communication according to the first embodiment, the reception level is lowered due to the change in the inclination of the polarization plane accompanying the change in the scanning angle of the combined beam of the antenna element patch group 2. Focusing on the patch inclination angle φ with respect to the X axis of the patch center line PC of each antenna element patch 2a, 2b,..., 2n, this patch inclination angle φ is set to a predetermined inclination angle Φ1. By doing so, the reduction of the reception level is improved. The setting of the patch inclination angle φ1 will be described in more detail.

  In the first embodiment, the change characteristic of the cross polarization component with respect to the change of the scanning angle of the combined beam of the antenna element patch group 2 in the phased array antenna 10 for mobile satellite communication is the patch tilt angle with respect to the X axis of the patch center line PC Based on the change corresponding to φ, the patch inclination angle φ is set to a predetermined inclination angle φ1 in relation to the change characteristic of the cross polarization component. The predetermined patch inclination angle φ1 with respect to the X axis of the patch center line PC of each antenna element patch 2a, 2b,..., 2n in the first embodiment is from the geostationary satellite indicated by an arrow A in FIG. When the azimuth inclination angle φ0 of the linearly polarized wave of the radio wave is φ0 = 7 degrees, it is set to 9 to 11 degrees, specifically 10 degrees.

  FIG. 3 shows the change characteristic of the cross polarization component with respect to the change of the scanning angle of the combined beam of the antenna element patch group 2 for the phased array antenna 10 for mobile satellite communication. In FIG. 3, the horizontal axis indicates the scanning angle of the combined beam, and the vertical axis indicates the cross polarization component. A straight line 8 indicates a specified level L0 of the cross polarization component defined for the antenna system including the phased array antenna 10 for mobile satellite communication, and is required to be a cross polarization component equal to or lower than the specified level L0. The dotted line characteristic 11 corresponds to the first embodiment. The patch inclination angle φ with respect to the X axis of the patch center line PC of each antenna element patch 2a, 2b,. And the characteristic of the cross polarization component when the unnecessary radiation of the feeder line 3 is ignored.

  The cross polarization component change characteristic 11 is a U-shaped characteristic having a minimum value Cmin approximately in the middle between the first scanning angle θ1 and the second scanning angle θ2. This characteristic 11 is a U-shaped characteristic in which the cross-polarized component monotonously increases on both sides of the minimum value Cmin. However, the cross-polarization characteristic is also obtained at the first scanning angle θ1 and at the second scanning angle θ2. The wave component is below the specified level L0 and is below the specified level L0 required from the antenna system.

  FIG. 4 shows a change in the inclination of the polarization plane of the combined beam with respect to the change in the scanning angle of the combined beam of the antenna element patch group 2. In FIG. 4, the horizontal axis indicates the scanning angle of the combined beam, and the vertical axis indicates the tilt angle of the polarization plane with respect to the XZ plane of the combined beam of the mobile satellite communication phased array antenna 10. The dotted line characteristic 21 corresponds to the case where the patch inclination angle Φ of the patch center line PC of each antenna element patch 2a, 2b,..., 2n is set to a predetermined inclination angle Φ1 = 10 degrees corresponding to the first embodiment. It is a characteristic. In this characteristic 21, between the first and second scanning angles θ1 and θ2, the inclination of the polarization plane of the combined beam of the antenna element patch group 2 is relatively about 8.6 degrees to about 5.3 degrees. It is changing at a large angle.

  In the first embodiment, the phase shifter group 5 scans the combined beam of the antenna element patch group 2 between the first scanning angle θ1 and the second scanning angle θ2 in the XZ plane of the triaxial coordinate 7. Further, the cross polarization component with respect to the change in the scanning angle of the combined beam becomes the minimum value Cmin between the first scanning angle θ1 and the second scanning angle θ2, and this minimum value Each antenna element patch 2a, 2b,... Has a U-shaped characteristic that increases on both sides of Cmin and has a required level L0 or less at the first and second scanning angles θ1, θ2. 2n is characterized in that each patch center line PC is arranged with a predetermined inclination angle φ1 with respect to the X-axis.

  In the first embodiment, it is possible to easily improve a decrease in reception level due to movement of a moving body without providing a polarization plane control unit as in the prior art.

Comparative example.
In this comparative example, the patch inclination angle φ with respect to the X axis of the patch center line PC of each antenna element patch 2a, 2b,..., 2n in the first embodiment is indicated by an arrow A in FIG. According to the azimuth inclination angle φ0 of the linearly polarized wave of the radio wave from the geostationary satellite, φ0 = 7 degrees. A characteristic 13 indicated by a solid line in FIG. 3 indicates a change characteristic of the cross polarization component of this comparative example. In this comparative example, as is clear from the characteristic 13 in FIG. 3, the cross polarization component is less than or equal to the specified level in the range where the scanning angle of the combined beam is close to the first scanning angle θ1, but the scanning angle of the combined beam However, in the range close to the second scanning angle θ2, since the cross-polarized line segment exceeds the specified level L0, the decrease in the reception level cannot be eliminated.

  Also, a characteristic 23 shown by a solid line in FIG. 4 indicates a change in the inclination of the polarization plane of the combined beam with respect to the XZ plane with respect to a change in the scanning angle of the combined beam of the antenna element patch group 2 in the comparative example. Between the first and second scanning angles θ 1 and θ 2, the characteristic 23 has a polarization plane tilt angle in the range of about 6.3 degrees to about 3.3 degrees, which is smaller than the characteristic 21. Has changed.

Embodiment 2. FIG.
In the second embodiment, the cross polarization component with respect to the change in the scanning angle of the combined beam of the antenna element group 2 including the unwanted radiation from the bent portion 3c of the feed line 3 of FIG. 1 is the first angle value θ1. It becomes a minimum value Cmin between the second angle value θ2, increases on both sides of the minimum value Cmin, and has a U-shaped characteristic that is not more than a specified level at the first and second angle values. Further, the patch inclination angle φ between the patch center line PC of each antenna element patch 2a, 2b,..., 2n and the X axis is set to a predetermined inclination angle φ2. The other configuration is the same as that of the first embodiment. The predetermined inclination angle φ2 is 11 to 13 degrees when the azimuth inclination angle φ0 of the linearly polarized wave of the radio wave from the geostationary satellite indicated by arrow A in FIG. Is set to 12 degrees.

  The dotted line characteristic 12 in FIG. 3 shows the change in the cross polarization component when the patch inclination angle φ of each antenna element patch 2a, 2b,..., 2n is set to a predetermined inclination angle φ2 according to the second embodiment. It is a characteristic. Compared to the characteristic 11, the characteristic 12 has an overall increase in the cross-polarized wave component, and the cross-polarized wave component is larger in the region closer to the second scanning angle θ2 than in the region closer to the first scanning angle θ1. It has increased. However, the characteristic 12 is the minimum value Cmin between the first scanning angle θ1 and the second scanning angle θ2, as in the first embodiment, and increases on both sides of the minimum value Cmin. The first and second scanning angles θ1 and θ2 have a U-shaped characteristic that is less than or equal to the required specified level L0. In this second embodiment, a polarization plane control unit is provided as in the first embodiment. In addition, it is possible to easily improve the reception level.

  A characteristic 22 indicated by a one-dot chain line in FIG. 4 indicates a change in the tilt angle of the polarization plane of the combined beam with respect to the XZ plane with respect to a change in the scanning angle of the combined beam in the second embodiment. This characteristic 22 is in a region closer to the characteristic 21 between the characteristics 21 and 23, and changes within a range of about 8.0 degrees to about 5.0 degrees between the scanning angles θ1 and θ2 of the combined beam. Yes.

Embodiment 3 FIG.
FIG. 5 is a plan view showing the arrangement of the antenna element patch group 2 of the third embodiment. The phased array antenna 10A for mobile satellite communication according to the third embodiment is a two-dimensional phased array antenna, and includes a plurality of antenna element patches 2a1, 2b1, ... 2n1, 2a2, 2a2, ... 2n2, ... 2n1, 2n2, ... 2nn are arranged in a matrix so that their respective center points C are transferred on X1, X2, ..., XN axes parallel to the X axis. Is done.

  In FIG. 5, the feed line 3 and the phase shifter group 5 are omitted, and details of each antenna element patch are omitted, but the patch centerlines PC of each antenna element patch are all X1, X2,. , The XN axis is inclined by a predetermined inclination angle φ1, and the same effect as in the first embodiment can be obtained, and the inclination angle φ of the patch center line PC of all antenna element patches is As in the second embodiment, if the predetermined inclination angle φ2 is set, the same effect as in the second embodiment can be obtained.

Embodiment 4 FIG.
FIG. 6 is a perspective view showing Embodiment 4 of the phased array antenna for mobile satellite communication according to the present invention. The same parts as those in FIG. 1A are denoted by the same reference numerals and description thereof is omitted.

  In the mobile satellite communication phased array antenna 10B of the fourth embodiment, the antenna element patches 2a, 2b,..., 2n all have the same size and shape. It is said. Further, the four sides of each antenna element patch 2a, 2b,..., 2n are arranged so as to be parallel to the X axis and the Y axis. Each of the antenna element patches 2a, 2b,..., 2n has two feeding points F1, F2, and these feeding points F1, F2 correspond to the antenna element patches 2a, 2b,. It is comprised in each middle point of 2 sides which adjoin and mutually orthogonally cross. In each antenna element patch 2a, 2b,..., 2n, two straight lines connecting the center point C and the feed points F1 and F2 are orthogonal to each other.

  The feed line 3 includes a branch line 3a and a common line 3b for each antenna element patch 2a, 2b,..., 2n, and each branch line 3a further includes a two-branch line 3d ′ that branches into two at a branch point 3d. . At the branch point 3d, an unequal distribution circuit is configured by making the line widths of the two branch lines 3d 'different from each other.

  In the fourth embodiment, the two branch lines 3d ′ constituting the unequal distribution circuit are connected to the feeding points F1 and F2 of the antenna element patches 2a, 2b,. A polarization component parallel to the X axis is received from the feed point F1, and a polarization component parallel to the Y axis is received from the other feed point F2, and these two polarization components are different from each other. The signals are combined at a ratio, and a reception signal is output to the reception output terminal 4 through the feed line 3.

  In the fourth embodiment, as in the first embodiment, the cross polarization component with respect to the change in the scanning angle of the combined beam of the antenna element patch group 2 is between the first scanning angle θ1 and the second scanning angle θ2. So as to have a U-shaped characteristic that increases on both sides of the minimum value Cmin and that is less than the required prescribed level L0 at the first and second scanning angles θ1 and θ2. The distribution ratio of each 2-branch line 3d 'and the length of the branched line of each 2-branch line 3d' are given. It is possible to improve a decrease in reception level due to movement.

  When unnecessary radiation having a certain polarization component is generated from the feed line 3, the distribution ratio of the unequal distribution circuit by the two-branch line 3 d ′ is changed, and this antenna element patch group 2 is synthesized including this unnecessary radiation. The cross polarization component with respect to the change in the scanning angle of the beam becomes a minimum value within the scanning range between the first and second scanning angles θ1 and θ2, increases on both sides of the minimum value, and at the scanning angles θ1 and θ2. By giving the distribution ratio of each two-branch line 3d ′ so as to have a U-shaped characteristic that is lower than the required level Lo, the generation of cross-polarized waves can be reduced and the branch line of each two-branch line 3d ′ By giving a difference in length, it is possible to suppress the occurrence of cross-polarization of circularly polarized waves, improve the decrease in reception level with a simple configuration using only a planar circuit, and there is an interference signal with orthogonal polarization High signal-to-interference It is possible to obtain.

  The phased array antenna for mobile satellite communication according to the present invention is mounted on a mobile body and used as a phased array antenna that receives radio waves from a geostationary satellite.

FIG. 1 shows a first embodiment of a phased array antenna for mobile satellite communication according to the present invention, FIG. 1 (a) is a perspective view thereof, and FIG. 1 (b) is a plan view of the antenna element patch. FIG. 2 is an explanatory diagram, FIG. 2 (a) shows the change in the slope of the polarization plane of the combined beam in the first embodiment, and FIG. 2 (b) shows the direction of linear polarization of radio waves from the geostationary satellite. . FIG. 3 is a characteristic diagram showing changes in cross polarization components. FIG. 4 is a characteristic diagram showing a change in the tilt angle of the polarization plane of the combined beam. FIG. 5 is a plan view showing a third embodiment of the phased array antenna for mobile satellite communication according to the present invention. FIG. 6 is a perspective view showing Embodiment 4 of the phased array antenna for mobile satellite communication according to the present invention.

Explanation of symbols

10, 10A, 10B: Phased array antenna for mobile satellite communication, 1: Dielectric substrate,
2, 2a, 2B, ..., 2n, 2a1, 2a2, ..., 2an, 2b1, 2b2, ...,
2bn, 2n1, 2n2, ..., 2nn: antenna element patch,
C: Center point, F, F1, F2: Feed point, PC: Patch center line, 3: Feed line
3a: branch line, 3b: common line, 3d: branch point, 3d ': two branch line,
4: Reception output terminals 5, 5a, 5b,..., 5n: phase shifters.

Claims (4)

A phased array antenna for mobile satellite communication that is mounted on a mobile body and receives radio waves from a geostationary satellite,
A dielectric substrate;
When the three-axis coordinates of the X axis, the Y axis, and the Z axis are assumed so that the principal surface of the dielectric substrate is located on the XY plane, the dielectric substrate is arranged along the X axis on the principal surface of the dielectric substrate. A plurality of antenna element patches arranged so that
A feed line disposed on the main surface of the dielectric substrate and connected to each antenna element patch;
A plurality of phase shifters disposed on the feeder line and connected to each of the antenna element patches;
The plurality of phase shifters are configured to scan the combined beam of each antenna element patch between a first scanning angle and a second scanning angle in the XZ plane of the three-axis coordinates,
Further, the cross polarization component with respect to the change in the scan angle of the combined beam becomes a minimum value between the first scan angle and the second scan angle, and increases on both sides of the minimum value. In each of the first and second scanning angles, each antenna element patch has a patch center line connecting a center point and a feeding point so that the antenna element patch has a U-shaped characteristic that is less than a required standard level. An antenna for mobile satellite communication, which is arranged at a predetermined inclination angle with respect to an X axis.   2. The phased array antenna for mobile satellite communication according to claim 1, wherein an inclination angle of each antenna element patch includes a change in a scanning angle of the combined beam including unnecessary radiation in a feed line with respect to each antenna element patch. The cross polarization component has a minimum value between the first scanning angle and the second scanning angle, and increases on both sides of the minimum value. Further, at the first and second scanning angles, there is a requirement. A phased array antenna for mobile satellite communication, which is set so as to have a U-shaped characteristic that is lower than a standard level. A phased array antenna for mobile satellite communication that is mounted on a mobile body and receives radio waves from a geostationary satellite,
A dielectric substrate;
When the three-axis coordinates of the X axis, the Y axis, and the Z axis are assumed so that the principal surface of the dielectric substrate is located on the XY plane, the dielectric substrate is arranged along the X axis on the principal surface of the dielectric substrate. A plurality of antenna element patches arranged so that
A feed line disposed on the main surface of the dielectric substrate;
With a plurality of phase shifters arranged on this feed line,
The feed line has a two-branch line between each phase shifter and the antenna element patch. The two-branch line has two feed points at different locations of the same antenna element patch, and the center of the antenna element patch. Configured so that two straight lines connecting a point and each of the feeding points are orthogonal to each other,
The plurality of phase shifters are configured to scan the combined beam of each antenna element patch between a first scanning angle and a second scanning angle in the XZ plane of the three-axis coordinates,
Further, the cross polarization component with respect to the change in the scan angle of the combined beam becomes a minimum value between the first scan angle and the second scan angle, and increases on both sides of the minimum value. The distribution ratio of the two-branch lines and the length of the two-branched lines are given so that the first and second scanning angles have a U-shaped characteristic that is equal to or less than the required specified level. A phased array antenna for mobile satellite communications. 4. The phased array antenna for mobile satellite communication according to claim 3, wherein a distribution ratio of the two-branch lines and a length of the two-branched lines include unnecessary radiation in a feed line for each antenna element patch, The cross polarization component with respect to the change in the scan angle of the combined beam has a minimum value between the first scan angle and the second scan angle, and increases on both sides of the minimum value. A phased array antenna for mobile satellite communications, which is set to have a U-shaped characteristic that is less than a required specified level at the second scanning angle.

Images