JP6203668B2 - Planar antenna inspection method and planar antenna - Google Patents

Description

  The present invention relates to a planar antenna inspection method and a planar antenna, and more particularly to a planar antenna on which a waveguide microstrip line converter is formed and an inspection method thereof.

  The microstrip antenna is a planar antenna configured by forming a circuit pattern made of a conductor layer on both surfaces of a dielectric substrate, and is fed using a waveguide. For example, a circuit pattern including a large number of radiating elements, a feeding circuit to the radiating elements, and a short-circuit plate is formed on the surface of the dielectric substrate, and a connection circuit for connecting a waveguide on the back surface of the dielectric substrate. And a circuit pattern including a ground plate is formed. Such a circuit pattern is formed by using a photolithography technique.

  In the case of a planar antenna, if there is a large shift in the position of the circuit pattern between the front surface and the back surface of the dielectric substrate, there is a problem that the radiation characteristics deteriorate and the front gain decreases. Conventionally, in the manufacturing process of a planar antenna, the finished product of a planar antenna is actually measured for radiation characteristics such as front gain, thereby estimating the front-to-back deviation as described above, and the finished product with a large front-to-back deviation as a defective product. Exclusion was done. However, measuring the radiation characteristics of all the finished products is extremely inefficient in production and increases the manufacturing cost of the planar antenna.

  The connection circuit includes a through hole provided in the ground plate in association with the waveguide, a matching element provided in the through hole, and the like. It constitutes a line converter. If a planar pattern on which such a waveguide microstrip line converter is formed is provided with a pattern for alignment, there is also a problem that radiation characteristics deteriorate.

  In Patent Document 1, the first detection unit 1 including the detector 11 and the illumination L1 is disposed on the front side of the substrate W, and the second detection unit 2 including the detector 12 and the illumination L2 is disposed on the back side of the substrate W. A misalignment inspection apparatus is described. In this misalignment inspection apparatus, the reflected light when the detection light is irradiated from the illumination L1 to the surface of the substrate W is detected by the detector 11, and the reflected light when the detection light is irradiated from the illumination L2 to the back surface of the substrate W. Is detected by the detector 12, and by combining these detection data, the positional deviation between the patterns respectively formed on both surfaces of the substrate is obtained.

  However, in such an inspection method using reflected light, there is a problem that detection accuracy of misalignment is low because fine irregularities and patterns on the substrate surface are easily erroneously detected as circuit patterns. In addition, in order to detect misalignment from detection data obtained by receiving reflected light on the front surface side of the dielectric substrate and detection data obtained by receiving reflected light on the back surface side of the dielectric substrate, It is necessary to accurately align these detection data. For this reason, there has been a problem that the positions and orientations of the detectors 11 and 12 must be calibrated in advance, or an alignment mark or the like must be provided in the imaging area of the detectors 11 and 12 in advance.

JP 2005-172540 A

  The present invention has been made in view of the above circumstances, and a planar antenna inspection method capable of detecting a positional deviation between circuit patterns formed on both surfaces of a dielectric substrate without measuring radiation characteristics. The purpose is to provide. In particular, it is an object of the present invention to provide a planar antenna inspection method capable of improving the detection accuracy of misalignment as compared with an inspection method that receives reflected light and detects misalignment. Another object of the present invention is to provide a planar antenna inspection method capable of detecting a positional deviation between circuit patterns constituting a waveguide microstrip line converter while suppressing deterioration of radiation characteristics.

  It is another object of the present invention to provide a planar antenna that can optically detect a positional shift between circuit patterns formed on both surfaces of a dielectric substrate without measuring radiation characteristics. . In particular, it is an object of the present invention to provide a planar antenna that can optically detect a positional shift between circuit patterns constituting a waveguide microstrip line converter while suppressing deterioration of radiation characteristics.

  A planar antenna inspection method according to a first aspect of the present invention is a planar antenna inspection method in which a waveguide microstrip line converter is formed, wherein the waveguide microstrip line converter is a first dielectric substrate. A first circuit pattern and a second circuit pattern formed on the surface and the second surface, respectively, wherein the second circuit pattern includes a rectangular through-hole provided in the ground plate in association with the waveguide; A first circuit pattern forming step of forming a first circuit pattern on the first surface of the dielectric substrate, the pattern including a short-circuit plate provided in association with the through hole, and including a first inspection pattern for alignment; A second circuit pattern forming step of forming a second circuit pattern including a second inspection pattern arranged in correspondence with the first inspection pattern on the second surface of the dielectric substrate; Based on the inspection pattern imaging step of receiving the transmitted light when illuminating the electrical substrate and generating an inspection pattern image including an inspection pattern set including the first inspection pattern and the second inspection pattern, A displacement determination step of determining displacement between the first circuit pattern and the second circuit pattern, and the inspection pattern set is formed at a position facing the short side of the through hole.

  In this planar antenna inspection method, since the first and second inspection patterns are formed as the first and second circuit patterns, respectively, an inspection pattern image obtained by photographing an inspection pattern set including the first and second inspection patterns is analyzed. By doing so, it is possible to determine the positional deviation between the first circuit pattern and the second circuit pattern. That is, it is possible to detect a positional shift between circuit patterns formed on both surfaces of the dielectric substrate without measuring the radiation characteristics.

  Further, since the inspection pattern image is obtained by receiving the transmitted light when the dielectric substrate is irradiated with the detection light, the detection accuracy of the positional deviation is improved as compared with the inspection method for detecting the positional deviation by receiving the reflected light. be able to. Further, the inspection pattern set is formed at a position facing the short side of the through hole provided in the ground plate in association with the waveguide. The long side and the short side of the through hole correspond to the wide wall and the narrow wall of the waveguide, respectively, and the electric field leakage in the direction intersecting the long side is larger than the direction intersecting the short side. For this reason, it can suppress that a radiation characteristic deteriorates compared with the case where a test | inspection pattern set is formed in the position facing the long side of a through-hole. Therefore, it is possible to detect a positional shift between circuit patterns constituting the waveguide microstrip line converter while suppressing deterioration of radiation characteristics.

  A planar antenna according to a second aspect of the present invention is a planar antenna in which a waveguide microstrip line converter is formed, is formed on a second surface of a dielectric substrate, and is provided on a ground plate in association with the waveguide. A first circuit pattern including a second circuit pattern including a rectangular through hole and a first circuit pattern including a short-circuit plate formed on the first surface of the dielectric substrate so as to correspond to the through hole. The circuit pattern includes a first inspection pattern for alignment, the second circuit pattern includes a second inspection pattern arranged in association with the first inspection pattern, and includes the first inspection pattern and the second inspection pattern. The inspection pattern set is configured to be formed at a position facing the short side of the through hole.

  In this planar antenna, the first and second inspection patterns are formed as the first and second circuit patterns, respectively. Therefore, by analyzing the inspection pattern image obtained by photographing the inspection pattern set including the first and second inspection patterns. The positional deviation between the first circuit pattern and the second circuit pattern can be determined. That is, it is possible to optically detect a positional shift between circuit patterns formed on both surfaces of the dielectric substrate without measuring the radiation characteristics. In addition, since the inspection pattern set is formed at a position facing the short side of the through hole provided in the ground plate in association with the waveguide, the positional deviation can be optically suppressed while suppressing deterioration of radiation characteristics. Can be detected.

  The planar antenna according to the third aspect of the present invention is configured such that, in addition to the above-described configuration, the two test pattern sets are arranged with the waveguide microstrip line converter interposed therebetween. According to such a configuration, it is possible to detect the positional deviation between the circuit patterns constituting the waveguide microstrip line converter, and to compare the positional deviation between the test pattern sets, thereby obtaining the first circuit pattern. And a relative rotational deviation between the second circuit patterns can be detected.

  A planar antenna according to a fourth aspect of the present invention includes, in addition to the above configuration, two or more of the waveguide microstrip line converters arranged on a straight line with the short sides of the through-holes facing each other, and the two inspection patterns The set is configured so as to be disposed with a converter row composed of the waveguide microstrip line converters interposed therebetween. According to such a configuration, it is possible to detect the positional deviation of the waveguide microstrip line converters in the arrangement direction and the rotational deviation of the transducer array with high accuracy.

  A planar antenna according to a fifth aspect of the present invention is configured such that, in addition to the above-described configuration, the inspection pattern set is disposed at a distance of 1/4 or more of the guide wavelength from the short-circuit plate. According to such a configuration, a test pattern set can be formed without degrading the radiation characteristics of the planar antenna and the conversion characteristics of the waveguide microstrip line converter.

  According to the present invention, it is possible to provide a planar antenna inspection method capable of detecting a positional deviation between circuit patterns formed on both surfaces of a dielectric substrate without measuring radiation characteristics. In particular, compared to inspection methods that detect reflected light by receiving reflected light, it is possible to improve the accuracy of detecting the displacement, and to construct a waveguide microstrip line converter while suppressing deterioration of radiation characteristics It is possible to detect a positional deviation between circuit patterns to be performed.

  Further, the planar antenna according to the present invention can optically detect a positional deviation between circuit patterns formed on both surfaces of the dielectric substrate without measuring the radiation characteristics. In particular, it is possible to optically detect a positional shift between circuit patterns constituting the waveguide microstrip line converter while suppressing deterioration of radiation characteristics.

It is the block diagram which showed one structural example of the planar antenna test | inspection apparatus 1 which test | inspects the front-and-back displacement of the planar antenna 2 by embodiment of this invention. It is the figure which showed one structural example of the planar antenna 2 of FIG. 1, and the surface of the planar antenna 2 is shown. It is sectional drawing which showed the structural example of the planar antenna 2 of FIG. 2, and the cut surface at the time of cut | disconnecting the planar antenna 2 by the AA cutting line is shown. It is sectional drawing which showed the structural example of the planar antenna 2 of FIG. 2, and the cut surface at the time of cut | disconnecting the planar antenna 2 by a BB cutting line is shown. FIG. 3 is a cross-sectional view illustrating a usage state of the planar antenna 2 of FIG. 2, in which a waveguide 6 is attached to a connection circuit 26 of the planar antenna 2. It is the figure which showed an example of operation | movement of the front-back displacement inspection apparatus 1 of FIG. 1, and the test | inspection pattern image 7 obtained by image | photographing the planar antenna 2 by transmitted illumination is shown. It is the figure which showed an example of the radiation characteristic of the planar antenna 2, and the fall amount of the front gain measured while changing the position shift between the circuit patterns 21 and 25 is shown. FIG. 10 is a diagram showing another configuration example of the planar antenna 2, and shows a case where six waveguide-MSL converters 4 are formed on the dielectric substrate 20. FIG. 6 is a diagram showing another configuration example of the planar antenna 2, and shows a case where one waveguide-MSL converter 4 is formed on the dielectric substrate 20.

In the following description, up, down, left, and right refer to up, down, left, and right with reference to the drawing sheet, and rotation refers to rotation based on a central axis perpendicular to the drawing sheet.
<Planar antenna inspection device 1>
FIG. 1 is a block diagram showing a configuration example of a planar antenna inspection apparatus 1 that inspects a front / back displacement of a planar antenna 2 according to an embodiment of the present invention. The planar antenna inspection apparatus 1 is an image measurement apparatus that optically detects the front / back deviation of the planar antenna 2, and includes a stage 10, a camera 11, an imaging control unit 12, an inspection pattern image storage unit 13, a front / back deviation determination unit 14, and It is comprised by the illuminating device 15.

  The stage 10 is a work table on which an inspection object is placed, and a detection area SA that transmits the detection light 3 emitted from the illumination device 15 is formed. The detection area SA is an area made of a translucent material such as transparent glass, and the planar antenna 2 to be inspected is placed in the detection area SA. The camera 11 is an imaging device that receives the transmitted light 3a transmitted through the inspection object and generates a captured image when the detection light 3 is irradiated onto the inspection object. The camera 11 is arranged above the stage 10 with the direction facing downward.

  The illumination device 15 is a light source device for transmitted illumination that irradiates the inspection object on the stage 10 with the detection light 3 from below. For example, visible light is used as the detection light 3. The planar antenna inspection apparatus 1 can measure the size and shape of an inspection object by extracting an edge in the captured image by analyzing a captured image obtained by capturing the inspection object on the stage 10.

  As will be described later, the planar antenna 2 is an inspection object in which a circuit pattern made of a conductor layer is formed on both surfaces of a dielectric substrate, and is provided with an inspection pattern for alignment. The inspection pattern provided on the surface of the dielectric substrate is a predetermined figure, for example, a geometric figure that can easily identify the center. On the other hand, the inspection pattern provided on the back surface of the dielectric substrate is composed of a figure having the same shape, that is, a figure having a similar shape, which is different in size from the surface inspection pattern, and is arranged substantially concentrically with the surface inspection pattern.

  The imaging control unit 12 controls imaging by the camera 11 and acquires a captured image obtained by capturing the planar antenna 2 on the stage 10. The imaging control unit 12 acquires an inspection pattern image obtained by capturing an inspection pattern and stores it in the inspection pattern image storage unit 13.

  The front / back deviation determination unit 14 reads and analyzes the inspection pattern image from the inspection pattern image storage unit 13 and determines the front / back deviation of the circuit pattern. The front / back deviation is a relative positional deviation or rotational deviation between circuit patterns formed on both surfaces of the dielectric substrate, and is determined by extracting an edge indicating an inspection pattern and specifying the center position of the edge. .

  For example, for the inspection pattern image, an image area for edge extraction is designated in advance as a measurement target area. Edge extraction is performed by analyzing a luminance change in the measurement target region to detect an edge point, and fitting a geometric figure such as a straight line, a circle, or an arc to the detected plurality of edge points. The positional deviation is obtained as a two-dimensional change in position between the center position of the edge indicating the inspection pattern on the front surface and the center position of the edge indicating the inspection pattern on the back surface.

  In the manufacturing process of the planar antenna 2, if the finished product of the planar antenna 2 is inspected using the planar antenna inspection apparatus 1, the front and back deviation of the circuit pattern is detected without actually measuring the radiation characteristics such as the front gain. be able to. Further, since the inspection pattern image is obtained by receiving the transmitted light 3a when the detection light 3 is applied to the dielectric substrate, the detection accuracy of the positional deviation is improved compared to the inspection method in which the reflected light is received and the positional deviation is detected. Can be improved.

  In addition, quality control is facilitated by measuring the radiation characteristics of the finished product after removing the finished product with a large positional deviation from the finished product of the planar antenna 2 as a defective product by such an optical inspection method. Therefore, the production efficiency can be remarkably improved.

<Planar antenna 2>
FIG. 2 is a diagram illustrating a configuration example of the planar antenna 2 of FIG. 1, and the surface of the planar antenna 2 is illustrated. In FIG. 2, a plane in which five waveguide-MSL (microstrip line) converters 4 and four test pattern sets 30 are formed on a rectangular dielectric substrate 20 whose longitudinal direction is the left-right direction. An antenna 2 is shown. 3 and 4 are cross-sectional views showing a configuration example of the planar antenna 2 of FIG. 2, and FIG. 3 shows a cut surface when the planar antenna 2 is cut along an AA cutting line. 4 shows a cut surface when the planar antenna 2 is cut along a BB cutting line.

  The planar antenna 2 is a microstrip antenna that supplies power to the radiating element 22 through the MSL 23, and is provided on the dielectric substrate 20, the circuit pattern 21 formed on the surface of the dielectric substrate 20, and the back surface of the dielectric substrate 20. The circuit pattern 25 is formed and two or more inspection pattern sets 30 are formed.

  The dielectric substrate 20 is an antenna substrate made of a dielectric material that transmits the detection light 3. For example, an insulating resin substrate made of a fluororesin having a small relative dielectric constant is used for the dielectric substrate 20. The circuit pattern 21 is made of a conductor layer, and includes two or more radiating elements 22, two or more MSLs 23, and two or more short-circuit plates 24. The MSL 23 is a power supply circuit to the radiating element 22, and includes a transmission line that extends substantially along the substrate surface of the dielectric substrate 20.

  The circuit pattern 25 is made of a conductor layer and includes two or more connection circuits 26 and a ground plate 29. The connection circuit 26 is a circuit pattern for connecting a waveguide (not shown), and includes a rectangular through hole 27 formed in the ground plate 29 and a matching element 28 formed in the through hole 27. Composed.

  The ground plate 29 is a circuit pattern that functions as a ground electrode for the MSL 23, and substantially covers the entire substrate surface of the dielectric substrate 20. The long side 27a and the short side 27b of the through hole 27 have dimensions corresponding to the wide wall and the narrow wall of the waveguide, respectively. The matching element 28 is a resonator that resonates electromagnetic waves, and is composed of one or more continuous regions formed in an island shape in the through hole 27. In this example, a matching element 28 made of one rectangular region is formed in the through hole 27. The short-circuit plate 24 is a circuit pattern for short-circuiting the waveguide, and is formed at a position facing the connection circuit 26.

  The waveguide-MSL converter 4 is a power supply port that performs power conversion using electromagnetic waves between the waveguide and the MSL 23, and includes the MSL 23, the short-circuit plate 24, and the connection circuit 26. The short-circuit plate 24 has a notch for arranging the MSL 23 extending in the vertical direction. The MSL 23 has one end straddling the long side 27 a of the through hole 27. The short-circuit plate 24 and the connection circuit 26 are formed for each waveguide-MSL converter 4.

  Each waveguide-MSL converter 4 is disposed on the center line 5 with the short side 27b of the through hole 27 intersecting with the center line 5 extending in the left-right direction. The center line 5 is a straight line connecting the midpoints of the short sides 27b. Each waveguide-MSL converter 4 is disposed on the center line 5 with the short sides 27b of the through holes 27 facing each other. A radiation pattern including one or more radiation elements 22 and MSLs 23 is formed for each waveguide-MSL converter 4 and is vertically symmetric with respect to the center line 5. The number of waveguide-MSL converters 4 and the shape of the radiation pattern are determined according to the performance, directivity, and number of channels required for the planar antenna 2.

  In this example, the waveguides connected by the first and second waveguide-MSL converters 4 from the left and the third to fifth waveguide-MSL converters 4 from the left. The tube size is different. In the first waveguide-MSL converter 4 from the left, the short-circuit plate 24 has one upper notch having a downward concave shape and one lower notch having an upward concave shape. A radiation pattern extending upward from the upper notch and a radiation pattern extending downward from the lower notch are formed. In the upper and lower radiation patterns, the MSL 23 branches into three in the middle, and each is connected to the radiation element 22.

  In the second waveguide-MSL converter 4 from the left, the short-circuit plate 24 has one upper notch made of a concave shape downward and one lower notch made of a concave shape upward. One radiating element 22 is connected to the MSL 23 extending upward from the upper notch, and one radiating element 22 is connected to the MSL 23 extending downward from the lower notch. In the third to fifth waveguide-MSL converters 4 from the left, each of the short-circuit plates 24 has two upper cutouts having a concave shape downward and two concave shapes having an upward concave shape. It has a lower notch. A radiation pattern is formed for each notch, and one radiating element 22 is connected to the MSL 23 extending upward from the upper notch, and one radiating element 22 is connected to the MSL 23 extending downward from the lower notch. Has been.

  Such circuit patterns 21 and 25 are manufactured by attaching a metal thin film, for example, copper foil, to the dielectric substrate 20 and patterning the metal thin film on the dielectric substrate 20 by etching or the like. The line width and the like of the MSL 23 are determined according to the frequency, bandwidth and radiation characteristics of electromagnetic waves to be transmitted / received. The line width of the MSL 23 is sufficiently shorter than the in-tube wavelength λg of the electromagnetic wave to be transmitted / received. The guide wavelength λg here is the wavelength of the electromagnetic wave propagating through the MSL 23 formed on the dielectric substrate 20.

  The inspection pattern set 30 is a symbol pair for detecting front / back deviation, which includes a front surface inspection pattern 31 provided on the surface of the dielectric substrate 20 and a back surface inspection pattern 32 provided on the back surface of the dielectric substrate 20. .

  The surface inspection pattern 31 is a positioning symbol made up of a figure whose center can be easily identified, and is formed on the dielectric substrate 20 simultaneously with the circuit pattern 21. For example, the surface inspection pattern 31 is a pattern made of the same metal material as the circuit pattern 21 and is formed in a patterning process common to the circuit pattern 21.

  The back surface inspection pattern 32 is an alignment symbol arranged in association with the front surface inspection pattern 31 and is formed on the dielectric substrate 20 simultaneously with the circuit pattern 25. For example, the back surface inspection pattern 32 is a conductor layer extraction pattern made of a through hole formed in the same metal material pattern as the circuit pattern 25, and is formed in a patterning process common to the circuit pattern 25. The back surface inspection pattern 32 is formed of a figure having the same shape (similar shape) different in size from the surface inspection pattern 31 and is arranged substantially concentrically with the surface inspection pattern 31.

  The shape and size of the front surface inspection pattern 31 and the back surface inspection pattern 32 are not particularly limited, but are geometric figures that can easily identify the center from the viewpoint of increasing the accuracy of detecting misalignment. Is desirable. Examples of the figure whose center can be easily specified include point-symmetric figures such as a circle, a rectangle, and a regular hexagon. Further, the size of the front surface inspection pattern 31 and the back surface inspection pattern 32 may be larger than the resolution of the camera 11.

  Further, the magnitude relationship between the front surface inspection pattern 31 and the back surface inspection pattern 32 is not particularly limited, but when the surface inspection pattern 31 and the back surface inspection pattern 32 are identified by analyzing a captured image using transmitted illumination. From the viewpoint of improving the identification accuracy, it is desirable that the front surface inspection pattern 31 is included in the back surface inspection pattern 32.

  In this example, a back surface inspection pattern 32 is formed by forming a circular through hole having a diameter larger than that of the surface inspection pattern 31 in the ground plate 29 so as to face the circular surface inspection pattern 31. And the back surface inspection pattern 32 is arranged concentrically.

  Since the inspection patterns 31 and 32 are patterns formed simultaneously with the circuit patterns 21 and 25, respectively, the positional deviation of the circuit patterns 21 and 25 is determined by analyzing the inspection pattern image obtained by photographing the inspection pattern set 30. be able to.

  The inspection pattern set 30 is formed at a position facing the short side 27 b of the through hole 27. Preferably, the inspection pattern set 30 is formed on the center line 5 formed by a straight line connecting the midpoints of the short sides 27b and at positions facing the short sides 27b. Specifically, the inspection pattern set 30 is arranged away from the short-circuit plate 24 so that the distance d between the surface inspection pattern 31 and the short-circuit plate 24 is ¼ or more of the guide wavelength λg.

  In this way, the inspection pattern set 30 is formed at a position facing the short side 27b of the through hole 27, so that the deterioration of the radiation characteristic is suppressed and the circuit pattern constituting the waveguide-MSL converter 4 is suppressed. Misalignment can be detected. In addition, since the test pattern set 30 is arranged at a distance of ¼ or more of the in-tube wavelength λg from the short-circuit plate 24, the radiation characteristics of the planar antenna 2 and the conversion characteristics of the waveguide-MSL converter 4 are not deteriorated. An inspection pattern set 30 can be formed.

  Each inspection pattern set 30 is formed on the same straight line (preferably on the center line 5) parallel to the long side 27a, and the first and fourth inspection pattern sets 30 from the left are the center line 5 They are arranged with a converter row composed of waveguide-MSL converters 4 arranged on the top. By configuring in this way, it is possible to detect the positional deviation of the waveguide-MSL converter 4 in the arrangement direction and the rotational deviation of the transducer array with high accuracy.

  FIG. 5 is a cross-sectional view showing a usage state of the planar antenna 2 of FIG. 2, and shows a state where the waveguide 6 is attached to the connection circuit 26 of the planar antenna 2. The waveguide 6 is formed of a hollow structure that transmits microwave or millimeter wave band electromagnetic waves in the tube axis direction. The waveguide 6 is attached to the planar antenna 2 with the upper end of the narrow wall 6 a aligned with the short side 27 b of the through hole 27.

  The tube axis of the waveguide 6 is perpendicular to the substrate surface of the dielectric substrate 20, and each waveguide 6 is disposed so as to protrude from the back surface of the dielectric substrate 20. The radiation characteristic of the planar antenna 2 is measured in such a use state.

<Inspection pattern image 7>
FIG. 6 is a diagram illustrating an example of the operation of the front / back displacement inspection apparatus 1 of FIG. 1, and shows an inspection pattern image 7 obtained by photographing the planar antenna 2 with transmitted illumination. In this inspection pattern image 7, an inspection pattern set 30 including a front surface inspection pattern 31 and a back surface inspection pattern 32 is imaged as a subject.

  In the front / back deviation detection process, first, by analyzing the inspection pattern image 7, a circle indicating the front surface inspection pattern 31 and a circle indicating the back surface inspection pattern 32 are extracted as edges. Next, the positions of the centers 31a and 32a of these circles are obtained, and the front / back deviation is determined from the change ΔZ of the center position.

  FIG. 7 is a diagram showing an example of the radiation characteristics of the planar antenna 2, and shows the amount of decrease in front gain measured while changing the positional deviation between the circuit patterns 21 and 25. In this figure, the horizontal axis represents the positional deviation (mm), the vertical axis represents the front gain reduction amount (dB), and the radiation characteristics in the case of transmitting and receiving millimeter-wave radio waves are shown.

  The front gain of the planar antenna 2 is decreased by 0 dB when the positional deviation is 0 mm, and monotonously decreases as the positional deviation increases. For example, when the positional deviation is 0.1 mm, the reduction amount is about −0.7 dB, and when the positional deviation is 0.2 mm, the reduction amount is about −2.6 dB. By preparing a table showing such radiation characteristics in advance, the radiation characteristics can be estimated from the positional deviation without actually measuring the radiation characteristics of the planar antenna 2. Inspection can be facilitated.

  According to the present embodiment, it is possible to detect a positional shift between the circuit patterns 21 and 25 formed on the dielectric substrate 20 without measuring the radiation characteristics. In addition, since the inspection pattern image 7 is obtained by receiving the transmitted light 3a when the detection light 3 is applied to the dielectric substrate 20, detection of misalignment is detected compared to the inspection method in which reflected light is received and misalignment is detected. Accuracy can be improved.

  FIG. 8 is a diagram showing another configuration example of the planar antenna 2, and shows a case where six waveguide-MSL converters 4 and four inspection pattern sets 30 are formed on the dielectric substrate 20. Has been. A radiation pattern composed of one or more radiation elements 22 and the MSL 23 is formed for each waveguide-MSL converter 4 and is asymmetrical with respect to the center line 5.

  The first to fifth waveguide-MSL converter 4 from the left and the sixth waveguide-MSL converter 4 from the left have different waveguide sizes. In the first to fourth waveguide-MSL converters 4 from the left, the short-circuit plate 24 has one lower notch having a concave shape upward, and the MSL 23 extends downward from the lower notch. One radiating element 22 is connected.

  In the fifth waveguide-MSL converter 4 from the left, the short-circuit plate 24 has one lower notch having a concave shape upward, and a radiation pattern extending downward from the lower notch is formed. Yes. In this radiation pattern, the MSL 23 branches into three in the middle, and each is connected to the radiation element 22.

  In the sixth waveguide-MSL converter 4 from the left, the short-circuit plate 24 has two lower notches that are concave upward. A radiation pattern is formed for each of these notches, and one radiation element 22 is connected to the MSL 23 extending downward from the lower notch.

  Each waveguide-MSL converter 4 and each inspection pattern set 30 are formed on the center line 5. Even with such a planar antenna 2, it is possible to detect a front-back deviation between the circuit patterns 21 and 25 by analyzing the inspection pattern image 7 obtained by photographing the inspection pattern set 30.

  FIG. 9 is a diagram showing another configuration example of the planar antenna 2, and shows a case where one waveguide-MSL converter 4 and two inspection pattern sets 30 are formed on the dielectric substrate 20. Has been. The waveguide-MSL converter 4 is disposed on the center line 8 with the short side 27b of the through hole 27 intersecting the center line 8 extending in the vertical direction. The center line 8 is a straight line connecting the midpoints of the short sides 27b.

  A radiation pattern composed of two or more radiation elements 22 and the MSL 23 is formed on the left and right of the waveguide-MSL converter 4. In the waveguide-MSL converter 4, the short-circuit plate 24 has one left cutout having a concave shape to the right and one right cutout having a concave shape to the left. A radiation pattern extending leftward from the notch and a radiation pattern extending rightward from the right notch are formed. In the left and right radiation patterns, a number of radiation elements 22 are connected to the MSL 23.

  Each inspection pattern set 30 is formed on the center line 8 and arranged with the waveguide-MSL converter 4 interposed therebetween. Even with such a planar antenna 2, it is possible to detect a front-back deviation between the circuit patterns 21 and 25 by analyzing the inspection pattern image 7 obtained by photographing the inspection pattern set 30.

  In the present embodiment, the detection light 3 is irradiated from the back side of the dielectric substrate 20 (side on which the back side inspection pattern 32 is formed), and on the front side (side on which the front side inspection pattern 31 is formed). The example in which the transmitted light 3a is received and the inspection pattern image of the inspection pattern set 30 is acquired has been described. However, the present invention irradiates the detection light 3 from the front side and the transmitted light 3a on the back side. A configuration in which an inspection pattern image is acquired by receiving light may be used. Further, in the present embodiment, an example in which the transmitted light 3a when the detection light 3 is irradiated onto the dielectric substrate 20 is received and the positional deviation is detected has been described. The present invention can also be applied to an inspection method in which reflected light when irradiated onto the body substrate 20 is received to detect misalignment.

DESCRIPTION OF SYMBOLS 1 Planar antenna inspection apparatus 10 Stage 11 Camera 12 Imaging control part 13 Inspection pattern image memory | storage part 14 Front and back deviation determination part 15 Illumination device 2 Planar antenna 20 Dielectric board | substrates 21 and 25 Circuit pattern 22 Radiation element 23 MSL
24 Shorting plate 26 Connection circuit 27 Through hole 27a Long side 27b Short side 28 Matching element 29 Grounding plate 30 Inspection pattern set 31 Surface inspection pattern 32 Back surface inspection pattern 3 Detection light 3a Transmission light 4 Waveguide-MSL converters 5, 8 Center line 6 Waveguide 6a Narrow wall 7 Inspection pattern image SA Detection region

Claims (5)

A method for inspecting a planar antenna on which a waveguide microstrip line converter is formed,
The waveguide microstrip line converter includes a first circuit pattern and a second circuit pattern formed on a first surface and a second surface of a dielectric substrate, respectively, and the second circuit pattern is associated with the waveguide. Including a rectangular through hole provided in the ground plate, the first circuit pattern including a short circuit plate provided in association with the through hole,
A first circuit pattern forming step of forming a first circuit pattern including a first inspection pattern for alignment on the first surface of the dielectric substrate;
A second circuit pattern forming step of forming a second circuit pattern including a second inspection pattern arranged in correspondence with the first inspection pattern on the second surface of the dielectric substrate;
A test pattern imaging step of receiving transmitted light when the dielectric substrate is irradiated with detection light and generating a test pattern image including a test pattern set including a first test pattern and a second test pattern;
A displacement determination step for determining displacement between the first circuit pattern and the second circuit pattern based on the inspection pattern image;
The planar antenna inspection method, wherein the inspection pattern set is formed at a position facing a short side of the through hole. In a planar antenna in which a waveguide microstrip line converter is formed,
A second circuit pattern formed on the second surface of the dielectric substrate and including a rectangular through hole provided in the ground plate in association with the waveguide;
A first circuit pattern including a short-circuit plate formed on the first surface of the dielectric substrate and provided in association with the through hole;
The first circuit pattern includes a first inspection pattern for alignment,
The second circuit pattern includes a second inspection pattern arranged in association with the first inspection pattern,
A planar antenna, wherein an inspection pattern set including a first inspection pattern and a second inspection pattern is formed at a position facing the short side of the through hole.   The planar antenna according to claim 2, wherein the two inspection pattern sets are arranged with the waveguide microstrip line converter interposed therebetween. Two or more waveguide microstrip line converters are arranged on a straight line with the short sides of the through holes facing each other,
The planar antenna according to claim 2 or 3, wherein the two inspection pattern sets are arranged with a converter row including the waveguide microstrip line converters interposed therebetween.   The planar antenna according to any one of claims 2 to 4, wherein the inspection pattern set is disposed at a distance of ¼ or more of the wavelength in the tube from the short-circuit plate.

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