Antenna equipment, transmitters, and radar

Abstract

The present invention provides an antenna device capable of suppressing unwanted radiation in the center feed. [Solution] The antenna device comprises a dielectric substrate and a conductor pattern formed on the dielectric substrate, the conductor pattern comprising a series antenna array including a plurality of patch antennas arranged in one direction and a transmission line connecting adjacent patch antennas among the plurality of patch antennas, and an input / output line for feeding power to the series antenna array, the input / output line being connected to the side to which the transmission line is connected of any patch antenna among the plurality of patch antennas, excluding the patch antennas at both ends.

Description

Technical Field

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[0001] The present invention relates to an antenna device, a transmitter, and a radar.

Background Art

[0002] Patent Documents 1 and 2 disclose a patch array antenna in which a plurality of patch antennas are arranged in one direction and connected in series.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0008] To solve the above problems, an antenna device according to one aspect of the present invention comprises a dielectric substrate, a series antenna array including a plurality of patch antennas formed on the dielectric substrate and arranged in one direction, and a transmission line connecting adjacent patch antennas among the plurality of patch antennas, and a conductor pattern comprising an input / output line for feeding power to the series antenna array, the input / output line being connected to the side of any of the plurality of patch antennas, excluding the patch antennas at both ends, to which the transmission line is connected. With this, by directly connecting the input / output line to the patch antennas, it is possible to eliminate the phase shifter and suppress unwanted radiation.

[0009] In the above embodiment, the transmission line may be connected to one side of the center of the side, and the input / output line may be connected to the other side. This makes it possible to suppress the influence of the input / output line on the transmission line.

[0010] In the above embodiment, the input / output line includes a first line section connected to one side of the first patch antenna in the one direction of any of the patch antennas, and a second line section connected to one side of the second patch antenna in the one direction of any of the patch antennas, wherein the length of the first line section and the second line section may be set so that no phase difference occurs in the fundamental waves input to the first and second patch antennas. This makes it possible to suppress some of the unwanted resonances.

[0011] In the above embodiment, the input / output line includes a first line section connected to one side of the first patch antenna in one direction among the patch antennas, and a second line section connected to the other side of the second patch antenna in one direction among the patch antennas, wherein the length of the first line section and the second line section may be set to produce a half-wavelength phase difference in the fundamental waves input to the first and second patch antennas. This makes it possible to suppress some of the unwanted resonances.

[0012] In the above embodiment, a connecting line may be further provided that connects the side of the first patch antenna to which the transmission line is connected to the side of the second patch antenna to which the transmission line is connected. This makes it possible to suppress some of the unwanted resonances.

[0013] In the above embodiment, the input / output lines may be arranged within the widthwise range of the patch antenna to which the input / output lines are connected. This makes it possible to suppress the spread in the widthwise direction.

[0014] In the above embodiment, the width of the patch antenna to which the input / output line is connected may be wider than the width of the patch antennas at both ends. This makes it possible to increase the coupling between the series antenna array and the input / output line.

[0015] Furthermore, another embodiment of the present invention includes the above-described antenna device. This makes it possible to realize a transmitter that includes an antenna device that suppresses unwanted radiation.

[0016] Furthermore, another embodiment of the present invention provides a radar with the above-described antenna device. This makes it possible to realize a radar that includes an antenna device that suppresses unwanted radiation. [Effects of the Invention]

[0017] According to the present invention, it is possible to suppress unwanted radiation in the center feed. [Brief explanation of the drawing]

[0018] [Figure 1] This is a diagram showing an example of radar. [Figure 2] This figure shows an example of an antenna device. [Figure 3] This figure shows an example of a conductor pattern according to the first embodiment. [Figure 4] This figure shows another example of the conductor pattern of the first embodiment. [Figure 5]It is a diagram showing a characteristic example of the conductor pattern of the first embodiment. [Figure 6] It is a diagram showing an example of the conductor pattern of the second embodiment. [Figure 7] It is a diagram showing an example of the conductor pattern of the third embodiment. [Figure 8] It is a diagram showing an example of the conductor pattern of the fourth embodiment. [Figure 9] It is a diagram showing an example of the conductor pattern of the fifth embodiment. [Figure 10] It is a diagram showing an example of the conductor pattern of the sixth embodiment. [Figure 11] It is a diagram showing another example of the conductor pattern of the sixth embodiment. [Figure 12] It is a diagram showing a characteristic example of the conductor pattern of the first embodiment. [Figure 13] It is a diagram showing a characteristic example of the conductor pattern of the third embodiment. [Figure 14] It is a diagram showing a characteristic example of the conductor pattern of the fifth embodiment. [Figure 15] It is a diagram showing a conventional conductor pattern.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and each figure, elements that are the same as those described above with respect to the already shown figures may be assigned the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0020] [Radar] FIG. 1 is a block diagram showing a configuration example of a radar 100. The radar 100 is an example of a transmitter. The radar 100 includes an antenna device 10, a transceiver unit 11, a signal processing unit 12, and a control unit 13.

[0021] The transmitting / receiving unit 11 includes a modulation unit and a magnetron. It intermittently drives the magnetron with a pulse voltage generated by the modulation unit in response to a trigger signal from the signal processing unit 12, thereby generating a transmission signal. The antenna device 10 transmits the transmission signal from the transmitting / receiving unit 11 as a radio wave pulse.

[0022] Furthermore, the antenna device 10 converts the received reflected wave into a received signal. The received signal from the antenna device 10 passes through the frequency conversion / amplification circuit and detection circuit included in the transmitting / receiving unit 11, is processed by the signal processing unit 12, and sent as a digital signal to the control unit 13.

[0023] The radar 100 is applied, for example, to an in-vehicle radar for obstacle detection or collision avoidance that transmits and receives millimeter waves. However, it is not limited to this, and the radar 100 may also be applied, for example, to a marine radar that transmits and receives microwaves.

[0024] [Antenna equipment] Figure 2 is a plan view showing an example of the configuration of the antenna device 10. The antenna device 10 comprises a dielectric substrate 2, a conductor pattern 3 formed on the first main surface 21 (the surface visible in the figure) of the dielectric substrate 2, and a ground pattern (not shown) formed on the second main surface of the dielectric substrate 2 opposite to the first main surface.

[0025] Conductor pattern 3 comprises a series antenna array 4 and input / output lines 5 for supplying power to the series antenna array 4. "Conductor pattern 3" is a general term for the conductor patterns 3A to 3F of each embodiment described later.

[0026] The series antenna array 4 is a series-fed patch array antenna and comprises a plurality of patch antennas 41-45 (also called antenna elements) arranged in one direction, and a plurality of transmission lines 46-49 connecting two adjacent patch antennas 41-45. The number of patch antennas 41-45 is not limited to the example shown.

[0027] In other words, in the series antenna array 4, patch antennas 41-45 are arranged alternately in one direction. As a result, the antenna device 10 as a whole has strong directivity. Transmission lines 46-49 are high-impedance lines with higher impedance than patch antennas 41-45.

[0028] The X1-X2 directions shown in the diagram represent the arrangement direction of patch antennas 41-45, the extension direction of transmission lines 46-49, and the transmission direction of radio waves in series antenna array 4. Hereafter, the X1-X2 directions will also be simply referred to as the "X direction." Furthermore, one side of the X direction (left in the diagram) will be referred to as the "X1 side," and the other side (right in the diagram) will be referred to as the "X2 side."

[0029] The Y1-Y2 direction, perpendicular to the X direction, corresponds to the width direction of the patch antennas 41-45 and the transmission lines 46-49. Hereafter, the Y1-Y2 direction will also simply be referred to as the "Y direction." Furthermore, one side of the Y direction (upward in the diagram) will be referred to as the "Y1 side," and the other side (downward in the diagram) will be referred to as the "Y2 side."

[0030] The patch antennas 41-45 are formed in a rectangular shape and have a transmission direction length X that corresponds to half a wavelength of the fundamental frequency used. That is, the transmission direction length X of the patch antennas 41-45 is approximately equal to half a wavelength of the fundamental frequency.

[0031] The input / output line 5 is connected to the feed point 9 and supplies power from the feed point 9 to the middle of the series antenna array 4 (so-called center feed). The feed point 9 is formed by a through-hole formed in the dielectric substrate 2.

[0032] The conductor pattern 3 is formed by patterning a metal foil provided on the first main surface 21 of the dielectric substrate 2 using photolithography technology. Therefore, the patch antennas 41-45, transmission lines 46-49, and input / output lines 5 are formed integrally.

[0033] Although only one series antenna array 4 is shown in the example in Figure 2, the antenna device 10 may be provided with multiple series antenna arrays 4 arranged in the width direction Y. Furthermore, some of the series antenna arrays 4 may be used for transmission and the others for reception.

[0034] Incidentally, in conventional examples, as shown in Figure 15, a phase shifter S, which is made up of a meander line, is installed between the feed point P of the transmission line L and one of the patch antennas B, thereby feeding power from the transmission line L to the patch antennas A and B on both sides with a 180-degree phase difference. As a result, the potentials of each patch antenna are aligned so that one end is positive and the other end is negative, and the radiated power from each patch antenna is combined.

[0035] However, the phase shifter S, which is composed of meandering lines, is prone to unwanted radiation due to the bends in the lines.

[0036] Therefore, in the embodiment described below, based on the idea that not only the antenna element but also the transmission line itself is in a resonant state, power is supplied directly from the radiating edge of the antenna element, which is easier to feed, rather than supplying power to the transmission line and disrupting the resonant state. This makes it possible to omit the phase shifter and suppress unwanted radiation, and to realize a standing wave-excited array antenna with a simple structure.

[0037] [First Embodiment] Figure 3 shows an example of a conductor pattern 3A in the first embodiment. In conductor pattern 3A, the input / output line 5 is directly connected to the side to which the transmission lines 46-49 are connected of any patch antenna 42-44, excluding the two end patch antennas 41 and 45 of the patch antennas 41-45. The side of the patch antennas 41-45 that is perpendicular to the transmission direction X and extends in the width direction Y is also called the radiation edge.

[0038] In the illustrated example, the input / output line 5 is connected to the X1 side edge 431 of the central patch antenna 43, to which the transmission line 47 is connected. In other words, two lines, the transmission line 47 and the input / output line 5, are connected to the X1 side edge 431 of the patch antenna 43. The patch antenna 43 is a 1-input, 2-output antenna element, with the input / output line 5 as the input and the transmission lines 47 and 48 as the outputs.

[0039] As a result, even without using the conventional phase shifter S (see Figure 15), the potentials of all patch antennas 41-45 can be aligned so that, for example, the X1 side is at a positive potential and the X2 side is at a negative potential, or vice versa.

[0040] In particular, a 180-degree phase difference can be introduced such that the X1 side 431 of the patch antenna 43 to which the input / output line 5 is connected is at a positive potential, and the X2 side 422 of the opposing patch antenna 42 is at a negative potential, or vice versa.

[0041] This makes it possible to suppress unwanted radiation while combining the radiated power from each patch antenna 41-45 to achieve the desired amount of radiation.

[0042] Figure 4 shows another example of the conductor pattern 3A of the first embodiment. In this example, a 41-stage patch array antenna is provided on the conductor pattern 1A. Figure 5 shows an example of the characteristics of this conductor pattern 3A. The horizontal axis represents the angle θ (deg), and the vertical axis represents the total gain (dB). From this, it can be seen that relatively high directivity is achieved.

[0043] As shown in Figures 3 and 4, in the series antenna array 4, patch antennas closer to the center are wider, and those further from the center are narrower, in order to increase the radiation amount and improve directivity. The input / output line 5 is connected to the relatively wide patch antennas.

[0044] For example, as shown in Figure 3, the width of the central patch antenna 43 is wider than the widths of the adjacent patch antennas 42 and 44, and even wider than the widths of the patch antennas 41 and 45 at both ends. The input / output line 5 is connected to the widest central patch antenna 43.

[0045] Since the total radiation amount of the series antenna array 4 depends on the coupling amount of the input / output structure to the series antenna array 4, by connecting the input / output line 5 to the relatively wide patch antennas in the series antenna array 4 and increasing the coupling amount, it is possible to increase the total radiation amount of the series antenna array 4 and achieve wider coverage.

[0046] [Second Embodiment] Figure 6 shows an example of the conductor pattern 3B of the second embodiment. In the conductor pattern 3B, the transmission line 47 is connected to the Y1 side in the width direction Y, and the input / output line 5 is connected to the Y2 side, with respect to the center of the X1 side edge 431 of the patch antenna 43. This makes it possible to suppress the influence of the input / output line 5 on the transmission line 47.

[0047] Of the transmission lines 46-49, transmission lines 46 and 48-49 are connected to the center of the Y-width of patch antennas 41-45, whereas transmission line 47, which is connected to the X1 side 431 of patch antenna 43 along with input / output line 5, is connected to a position offset from the center of the Y-width of patch antennas 42 and 43. In other words, neither transmission line 47 nor input / output line 5 is located on the center of the Y-width of patch antenna 43.

[0048] [Third Embodiment] Figure 7 shows an example of a conductor pattern 3C in the third embodiment. In the conductor pattern 3C, the input / output line 5 includes a plurality of line sections 52, 53 branched from the common section 51. Line section 52 is connected to the X1 side edge 421 of the patch antenna 42, and line section 52 is connected to the X1 side edge 441 of the patch antenna 44.

[0049] The lengths of the transmission lines 52 and 53 are set so that no phase difference occurs in the fundamental waves input to the patch antennas 42 and 44. For example, the transmission lines 52 and 53 are the same length. However, there may be a difference between them equal to an integer multiple of the wavelength of the fundamental wave.

[0050] As a result, the fundamental wave input from the transmission line 51 to the X1 side edge 421 of the patch antenna 42 and the fundamental wave input from the transmission line 52 to the X1 side edge 441 of the patch antenna 44 are in phase.

[0051] The diagram is not limited to the illustrated example; for example, the line section 52 may be connected to the X2 side edge 422 of the patch antenna 42, and the line section 53 may be connected to the X2 side edge 442 of the patch antenna 44. Furthermore, the line sections 52 and 53 may be connected to other patch antennas. Also, the number of line sections 52 and 53 may be three or more.

[0052] In standing wave-excited array antennas, increasing the number of elements leads to the generation of many unwanted resonances and a narrowing of the bandwidth. This is because unwanted resonances are frequency multipliers that resonate along the entire length of the antenna, and the number of resonant modes increases as the antenna length increases. This embodiment was made in view of this problem, and by feeding power to multiple elements, it is possible to suppress some of the unwanted resonances.

[0053] Figure 12 shows an example of the reflection characteristics of the 41-element patch array antenna of the first embodiment (a type in which power is supplied to only one central element). Figure 13 shows an example of the reflection characteristics of the 41-element patch array antenna of the third embodiment (a type in which power is supplied in phase to the same side of multiple elements). The horizontal axis represents frequency (MHz), and the vertical axis represents gain (dB).

[0054] In the first embodiment shown in Figure 12, large resonance modes are observed at 23.5 GHz and 24.5 GHz in addition to 24 GHz, whereas in the third embodiment shown in Figure 13, unwanted resonances at 23.5 GHz and 24.5 GHz are suppressed. In this way, desired antenna characteristics can be obtained over a wide frequency range.

[0055] [Fourth Embodiment] Figure 8 shows an example of a conductor pattern 3D in the fourth embodiment. In the conductor pattern 3C, the line portion 52 is connected to the X1 side edge 421 of the patch antenna 42, and the line portion 53 is connected to the X2 side edge 432 of the patch antenna 43.

[0056] The transmission lines 52 and 53 are set to a length such that a half-wavelength phase difference occurs in the fundamental wave input to the patch antennas 42 and 43. For example, there is a half-wavelength difference between the transmission lines 52 and 53. However, the difference between them may be an integer multiple of the fundamental wave wavelength or a half-wavelength.

[0057] As a result, the fundamental wave input from the transmission line 51 to the X1 side side 421 of the patch antenna 42 and the fundamental wave input from the transmission line 52 to the X2 side side 432 of the patch antenna 44 are in opposite phase. In this embodiment as well, similar to the third embodiment described above, it is possible to suppress some of the unwanted resonances.

[0058] [Fifth Embodiment] Figure 9 shows an example of a conductor pattern 3E according to the fifth embodiment. The conductor pattern 3E further includes a connecting line 6 that connects side 422 to which the transmission line 47 of patch antenna 42 (one of the patch antennas 41-45) is connected, and side 442 to which the transmission line 49 of patch antenna 44 is connected.

[0059] Specifically, the connecting line 6 connects the X2-side side 422 of patch antenna 42 and the X2-side side 442 of patch antenna 44, and has a length that is an integer multiple of the wavelength of the fundamental wave. This makes it possible to align the potential of the X2-side side 422 of patch antenna 42 and the X2-side side 442 of patch antenna 44.

[0060] As a result, in this embodiment as well, it is possible to suppress some of the unwanted resonances, similar to the third and fourth embodiments described above.

[0061] In addition to the illustrated example, the connecting line 6 may connect the X1 side 421 of patch antenna 42 and the X1 side 441 of patch antenna 44, and may have a length that is an integer multiple of the wavelength of the fundamental wave. Furthermore, the connecting line 6 may be connected to other patch antennas.

[0062] Furthermore, the connecting line 6 is formed between the X1 side 421 of the patch antenna 42 and the X2 side 442 of the patch antenna 44, and may have a length that is an integer multiple of the wavelength of the fundamental wave and half a wavelength. This also makes it possible to suppress some of the unwanted resonances.

[0063] Figure 14 shows an example of the reflection characteristics of a 41-element patch array antenna (a type in which multiple elements are linked together) according to the fifth embodiment. In the fifth embodiment shown in Figure 14, it can be seen that unwanted resonances at 23.5 GHz and 24.5 GHz are suppressed. This also makes it possible to obtain the desired antenna characteristics over a wide frequency range.

[0064] [Sixth Embodiment] Figure 10 shows an example of a conductor pattern 3F according to the sixth embodiment. In the conductor pattern 3F, the input / output line 5 and the feed point 9 are arranged within the width Y range of the series antenna array 4.

[0065] Specifically, the input / output line 5 and the feed point 9 are formed within the width Y range of the widest patch antenna 43 to which the input / output line 5 is connected. More precisely, the positions of the input / output line 5 and the feed point 9 in the width Y direction are located inward relative to the sides 433 and 434 that are opposite the width Y direction of the patch antenna 43 and extend in the array direction X.

[0066] The input / output line 5 extends linearly from the feed point 9 to the X1 side edge 431 of the patch antenna 43. Furthermore, the input / output line 5 is formed parallel to the transmission line 47 connected to the same X1 side edge 431 of the patch antenna 43.

[0067] By arranging the input / output lines 5 and the feed point 9 within the width Y range of the series antenna array 4 in this way, it becomes possible to make the series antenna array 4 more compact in the width Y direction and save space. In particular, as shown in Figure 11, when arranging multiple series antenna arrays 4 in the width Y direction, it becomes possible to reduce the spacing between them.

[0068] Of the multiple series antenna arrays 4 shown in Figure 11, some series antenna arrays 4 are used as transmitting antennas 40T, and the other series antenna arrays 4 are used as receiving antennas 40R. This allows the antenna device 10 to function as a MIMO (Multi Input Multi Output) antenna.

[0069] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are of course possible for those skilled in the art.

[0070] The following lists representative embodiments of the present invention.

[0071] (1) Dielectric substrate and Formed on the dielectric substrate, A series antenna array including a plurality of patch antennas arranged in one direction and a transmission line connecting adjacent patch antennas among the plurality of patch antennas, An input / output line for supplying power to the series antenna array, wherein the input / output line is connected to the side to which the transmission line is connected of any of the patch antennas among the plurality of patch antennas, excluding the patch antennas at both ends, A conductor pattern comprising, An antenna device equipped with the following features.

[0072] (2) The transmission line is connected to one side of the center of the aforementioned side, and the input / output line is connected to the other side. (1) The antenna device described above.

[0073] (3) The aforementioned input / output line is A first line section connected to one side of the first patch antenna in the aforementioned direction, A second line section connected to one side of the aforementioned one-way direction of the second patch antenna among the aforementioned patch antennas, Includes, The first line section and the second line section are set to a length such that no phase difference occurs in the fundamental waves input to the first and second patch antennas. The antenna device described in (1) or (2).

[0074] (4) The aforementioned input / output line is A first line section connected to one side of the first patch antenna in the aforementioned direction, A second line section connected to the other side of the one direction of the second patch antenna among the aforementioned patch antennas, Includes, The first line section and the second line section are set to a length such that a half-wavelength phase difference occurs in the fundamental waves input to the first and second patch antennas. The antenna device described in (1) or (2).

[0075] (5) The system further includes a connecting line that connects the side of the first patch antenna to which the transmission line is connected and the side of the second patch antenna to which the transmission line is connected. An antenna device as described in any of (1) through (4).

[0076] (6) The input / output lines are arranged within the widthwise range of the patch antenna to which the input / output lines are connected. An antenna device as described in any of (1) through (5).

[0077] (7) The width of the patch antenna to which the input / output line is connected is wider than the width of the patch antennas at both ends. An antenna device as described in any of (1) through (6).

[0078] (8) A transmitter equipped with an antenna device as described in any of (1) through (7).

[0079] (9) A radar equipped with an antenna device as described in any of (1) through (7). [Explanation of symbols]

[0080] 2 Dielectric substrate, 21 First main surface, 3 Conductor pattern, 4 Series antenna array, 41-45 Patch antennas, 46-49 Transmission lines, 5 Input / output lines, 9 Feed point, 10 Antenna device, 11 Transceiver unit, 12 Signal processing unit, 13 Control unit, 100 Radar

Claims

1. Dielectric substrate and Formed on the dielectric substrate, A series antenna array including a plurality of patch antennas arranged in one direction and a transmission line connecting adjacent patch antennas among the plurality of patch antennas, An input / output line for supplying power to the series antenna array, wherein the input / output line is connected to the side to which the transmission line is connected of any of the patch antennas among the plurality of patch antennas, excluding the patch antennas at both ends, A conductor pattern comprising, An antenna device equipped with the following features.

2. The transmission line is connected to one side of the center of the aforementioned side, and the input / output line is connected to the other side. The antenna device according to claim 1.

3. The aforementioned input / output line is A first line section connected to one side of the first patch antenna in the aforementioned direction, A second line section connected to one side of the aforementioned one-way direction of the second patch antenna among the aforementioned patch antennas, Includes, The first line section and the second line section are set to a length such that no phase difference occurs in the fundamental waves input to the first and second patch antennas. The antenna device according to claim 1.

4. The aforementioned input / output line is A first line section connected to one side of the first patch antenna in the aforementioned direction, A second line section connected to the other side of the one direction of the second patch antenna among the aforementioned patch antennas, Includes, The first line section and the second line section are set to a length such that a half-wavelength phase difference occurs in the fundamental waves input to the first and second patch antennas. The antenna device according to claim 1.

5. The system further includes a connecting line that connects the side of the first patch antenna to which the transmission line is connected and the side of the second patch antenna to which the transmission line is connected. The antenna device according to claim 1.

6. The input / output lines are arranged within the widthwise range of the patch antenna to which the input / output lines are connected. The antenna device according to claim 1.

7. The width of the patch antenna to which the input / output line is connected is wider than the width of the patch antennas at both ends. The antenna device according to claim 1.

8. A transmitter comprising the antenna device described in claim 1.

9. A radar comprising the antenna device described in claim 1.

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