Composite antenna device

Abstract

Provided is a composite antenna device that prevents a reduction in radiation efficiency due to the generation of a reverse current, has good antenna characteristics, and is easy to power. The composite antenna device is composed of a dipole antenna element (10) and a circularly polarized antenna element (20). The dipole antenna element (10) includes: a first hot terminal (11), a ground terminal (12), a first element (13) extending from the first hot terminal (11), and a second element (14) extending from the ground terminal (12). The circularly polarized antenna element (20) includes: a second hot terminal (21) disposed on a straight line connecting the first hot terminal (11) and the ground terminal (12) in a manner sandwiched between the first hot terminal (11) and the ground terminal (12); a third element (22) extending from the second hot terminal (21); and a fourth element (23) extending from the ground terminal (12) in a direction perpendicular to the third element (22).

Description

Technical Field

[0001] The present invention relates to a composite antenna device, and more particularly to a film-type composite antenna device for vehicle mounting. Background Art

[0002] Antennas mounted on vehicles such as automobiles that can receive circularly polarized waves represented by GPS are generally known to be patch antennas composed of microstrip antennas, and film-type antennas in which element patterns are arranged have also been developed.

[0003] As such a circularly polarized wave handling antenna, there is known Patent Document 1 proposed by the same applicant as the applicant of the present application. The circularly polarized wave handling antenna has a first element extending from a hot terminal and a second element extending from a ground terminal in a direction perpendicular to the first element, and has a structure in which these are surrounded by a loop element extending from the ground terminal and returning to the ground terminal.

[0004] In addition, as in Patent Document 2, there is also known a film antenna in which a part of a loop antenna is deformed into a convex shape in order to reduce the mounting area.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-151624

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-37799 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] In recent years, in order to cope with more frequency bands, a film-type composite antenna device equipped with multiple antenna elements has been developed. In the film-type composite antenna device for vehicle use, there are restrictions on the installation area, so the antenna elements and connection terminals become dense. At this time, for example, in Patent Document 1, a reverse current is generated between the hot terminal and the ground terminal, so if the hot terminal and the ground terminal exist nearby, there is a case where the radiation efficiency is reduced. In addition, in the element that is deformed into a convex shape in Patent Document 2, a reverse current is also generated in the opposite part, so there is a case where the radiation efficiency is reduced.

[0011] In view of the above-mentioned actual situation, an object of the present invention is to provide a composite antenna device which prevents a reduction in radiation efficiency due to generation of a reverse current, has good antenna characteristics, and is easy to supply power.

[0012] Solutions for solving problems

[0013] In order to achieve the above-mentioned purpose of the present invention, the composite antenna device of the present invention comprises: a dipole antenna element, which includes: a first hot terminal, a ground terminal, a first element extending from the first hot terminal, and a second element extending from the ground terminal; and a circularly polarized antenna element, which includes: a second hot terminal, which is arranged on a straight line connecting the first hot terminal and the ground terminal in a manner of being sandwiched between the first hot terminal and the ground terminal; a third element, which extends from the second hot terminal; and a fourth element, which extends from the ground terminal in a direction perpendicular to the third element.

[0014] However, the dipole antenna element may be a loop-shaped antenna element connecting the top end of the first element and the top end of the second element.

[0015] Furthermore, the dipole antenna element may include a parasitic element disposed near the tips of the first element and the second element in a capacitive coupling manner.

[0016] In addition, the first hot terminal, the second hot terminal, and the ground terminal may be covered by a module terminal including a transceiver.

[0017] It is also possible to further include a ground loop element, which extends from the ground terminal, passes between the first thermal terminal and the second thermal terminal, and returns to the ground terminal in a manner surrounding the second thermal terminal, the third element, and the fourth element.

[0018] In addition, the ground loop element only needs to have a side extending parallel to the dipole antenna element.

[0019] In addition, the ground loop element can be roughly square.

[0020] The device may further include a second parasitic element, the second parasitic element being arranged in the ground loop element and being arranged near the tips of the third element and the fourth element in a capacitive coupling manner.

[0021] In addition, the second parasitic element only needs to have a side extending parallel to the ground loop element.

[0022] Effects of the Invention

[0023] The composite antenna device of the present invention has the advantages that a decrease in radiation efficiency due to the generation of a reverse current is prevented, antenna characteristics are improved, and power supply is easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic plan view for explaining the composite antenna device of the present invention.

[0025] Figure 2 It is a schematic plan view for explaining another example of the composite antenna device of the present invention.

[0026] Figure 3 It is a schematic plan view for explaining another example of the composite antenna device of the present invention.

[0027] Figure 4 It is a schematic plan view for explaining another example of the composite antenna device of the present invention.

[0028] Figure 5 It is a schematic plan view for explaining another example of the composite antenna device of the present invention. DETAILED DESCRIPTION

[0029] Hereinafter, specific embodiments will be described together with illustration examples. Figure 1 1 is a schematic top view for explaining the composite antenna device of the present invention. As shown in the figure, the composite antenna device of the present invention is mainly composed of a dipole antenna element 10 and a circularly polarized antenna element 20. The dipole antenna element 10 and the circularly polarized antenna element 20 can be formed using conductive members such as conductive metal thin wires and conductive metal foils. These elements are arranged on a transparent film 1 of a dielectric, and the film 1 is pasted on a car window. In addition, when the antenna is embedded in a resin body, the element can also be directly arranged in the resin of the body.

[0030] The dipole antenna element 10 is composed of a first hot terminal 11 , a ground terminal 12 , a first element 13 , and a second element 14 .

[0031] The first element 13 extends from the first thermal terminal 11. In the example shown in the figure, the first element 13 extends from the thermal terminal 11 in an inverted L shape toward the bottom of the figure. More specifically, the first element 13 extends from the upper right corner of the first thermal terminal 11 to the right side in the horizontal direction, bends 90 degrees in the middle and extends downward. In addition, in the present invention, the first element 13 is not limited to the case of being bent into an inverted L shape, and can also extend only to the right side in the horizontal direction from the first thermal terminal 11. For example, the length of the first element 13 can be adjusted based on λ / 4 of the target frequency. Specifically, for example, the frequency band used for LPWA (Low Power Wide Area) can be adjusted as the target frequency.

[0032] The second element 14 extends from the ground terminal 12. In the example shown in the figure, the second element 14 extends to the left from the ground terminal 12. More specifically, the second element 14 extends to the left in the horizontal direction from the upper left corner of the ground terminal 12. For example, the length of the second element 14 may be adjusted based on λ / 4 of the target frequency. Specifically, for example, the frequency band used for LPWA (Low Power Wide Area) may be adjusted as the target frequency.

[0033] The dipole antenna element 10 is composed of two elements using the first element 13 and the second element 14 .

[0034] The circularly polarized antenna element 20 is composed of a second hot terminal 21 , a third element 22 , and a fourth element 23 .

[0035] The second thermal terminal 21 is arranged on a straight line connecting the first thermal terminal 11 and the ground terminal 12 in a manner sandwiched between the first thermal terminal 11 and the ground terminal 12. That is, the second thermal terminal 21 is interposed between the first thermal terminal 11 and the ground terminal 12. Therefore, even if a reverse current ( Figure 1 The current flowing in the direction indicated by the arrow is also abolished due to the shielding effect brought about by the presence of the second thermal terminal 21, thereby preventing the radiation efficiency from being reduced.

[0036] The third element 22 extends from the second thermal terminal 21. In the example shown in the figure, the third element 22 extends from the second thermal terminal 21 to the bottom of the figure. More specifically, the third element 22 extends downward from the lower right corner of the second thermal terminal 21. For example, the third element 22 may be adjusted based on λ / 4 of the target frequency so that the length of the third element 22 is shorter than the target frequency. Specifically, for example, the frequency band used for GNSS may be adjusted as the target frequency.

[0037] The fourth element 23 extends from the ground terminal 12 in a direction perpendicular to the third element 22. That is, the ground terminal 12 becomes a common terminal common to the second element 14 and the fourth element 23. The third element 22 and the fourth element 23 are arranged so as to form an angle of 90 degrees. More specifically, the fourth element 23 extends from the lower left corner of the ground terminal 12 to the left. In addition, for example, the length of the fourth element 23 may be adjusted based on λ / 4 of the target frequency so as to be longer than the reference.

[0038] By adjusting the lengths of the third element 22 and the fourth element 23 so that the current phase of the third element 22 is delayed by 45 degrees and the current phase of the fourth element 23 is advanced by 45 degrees, the current phase difference between the two elements becomes 90 degrees, and circularly polarized waves can be handled.

[0039] In addition, the lengths of the third element 22 and the fourth element 23 may be opposite to the above-mentioned structure, and the length of the third element 22 may be adjusted based on λ / 4 of the target frequency so that the length is longer than the reference, and the length of the fourth element 23 may be adjusted based on λ / 4 of the target frequency so that the length is shorter than the reference. The circularly polarized antenna element 20 of the composite antenna device of the present invention may also cope with either the left circularly polarized wave or the right circularly polarized wave in this way. In addition, the lengths of the third element 22 and the fourth element 23 may be set to the same length, in which case a phase shifter may be provided so that the current phase difference of the two elements is 90 degrees.

[0040] Among them, the first hot terminal 11, the second hot terminal 21 and the ground terminal 12 are connected to the equipment in the vehicle by means of a pickup, a cable, a module terminal, etc. In the composite antenna device of the present invention, as described above, the first hot terminal 11, the second hot terminal 21 and the ground terminal 12 are arranged on a straight line. Therefore, for example, in the case of using a module terminal 30 with a built-in transceiver, it can be easily designed so that the connection terminals can be arranged on the first hot terminal 11, the second hot terminal 21 and the ground terminal 12. That is, the first hot terminal 11, the second hot terminal 21 and the ground terminal 12 can be arranged in a manner covered by the module terminal 30 including the transceiver.

[0041] Next, use Figure 2 Another example of the composite antenna device of the present invention will be described. Figure 2 1 is a schematic top view for explaining another example of the composite antenna device of the present invention. Figure 1 Parts with the same reference numerals as those in the figure represent the same objects. In this example, the dipole antenna element 10 is composed of a ring-shaped antenna element 15 connecting the top of the first element 13 and the top of the second element 14. The ring-shaped antenna element 15 is configured to surround the third element 22 and the fourth element 23. As shown in the figure, the approximately square ring-shaped antenna element 15 is configured to surround the outermost periphery of the composite antenna device of the present invention. Depending on the target frequency of the dipole antenna element 10, it may sometimes be set to such a structure. In addition, the present invention is not limited to this, and it may also be rectangular or circular.

[0042] Next, use Figure 3 Another example of the composite antenna device of the present invention will be described. Figure 3 1 is a schematic top view for explaining another example of the composite antenna device of the present invention. Figure 1 The parts with the same reference numerals as those in the reference numerals in the figure represent the same items. In this example, the dipole antenna element 10 has a parasitic element 16. The parasitic element 16 is arranged near the top of the first element 13 and the second element 14 in a capacitive coupling manner. The parasitic element 16 is arranged so as to surround the third element 22 and the fourth element 23 together with the first element 13 and the second element 14. That is, in terms of electricity, the top of the first element 13 and the top of the second element 14 are connected by the parasitic element 16 to form a loop antenna element. Figure 2 The electrical performance of the dipole antenna element 10 is the same as the electrical performance of the dipole antenna element 10.

[0043] If the composite antenna device of the present invention is attached to a vehicle window, etc., the performance of the dipole antenna element 10 is affected by the size and position of the vehicle in which it is installed. Figure 2 Such a structure of the loop-shaped antenna element 15 or Figure 3 Such a structure using the parasitic element 16 may be affected by the metal part of the vehicle due to a difference in the installation position, and the performance at low elevation angles in the horizontal plane may be improved in the structure using the parasitic element 16 .

[0044] Next, use Figure 4 Another example of the composite antenna device of the present invention will be described. Figure 4 1 is a schematic top view for explaining another example of the composite antenna device of the present invention. Figure 1 The parts with the same reference numerals as those in the figure represent the same objects. In this example, the composite antenna device of the present invention further has a ground loop element 24. The ground loop element 24 extends in a ring shape from the ground terminal 12. Specifically, the ground loop element 24 is configured as follows: starting from the ground terminal 12, passing between the first hot terminal 11 and the second hot terminal 21, surrounding the second hot terminal 21, the third element 22 and the fourth element 23 and returning to the ground terminal 12. That is, all the terminals and elements of the circularly polarized antenna element 20 are configured in a manner surrounded by the ground loop element 24. In the example shown in the figure, an example in which the ground loop element 24 is roughly square is shown. In addition, the ground loop element 24 is configured in a manner having sides extending parallel to the third element 22 and the fourth element 23.

[0045] In addition, the first thermal terminal 11, the second thermal terminal 21 and the ground terminal 12 do not all need to be the same size. As shown in the figure, the second thermal terminal 21 can be lowered as long as it is arranged on the straight line connecting the first thermal terminal 11 and the ground terminal 12. In the example shown in the figure, the ground loop element 24 passes through the portion where its height is lowered.

[0046] Among them, Figure 1 to Figure 3 In the example shown, the dipole antenna element 10 and the circularly polarized antenna element 20 are preferably arranged separately, and the separation distance is such that the reception of the circularly polarized wave signal is not adversely affected by the mutual interference between the dipole antenna element 10 and the circularly polarized antenna element 20. Specifically, when the dipole antenna element 10 is used for LPWA, LPWA is mainly vertically polarized waves, and therefore the antenna characteristics of vertically polarized waves are emphasized. Therefore, there is a case where the first element 13 is not as Figure 1 As shown in the figure, it is better to be bent into an inverted L shape and extend downward from the first thermal terminal 11. However, when the first element 13 is extended directly downward from the first thermal terminal 11, the distance between the first element 13 and the circularly polarized antenna element 20 becomes closer, which may have an adverse effect on the circularly polarized antenna element 20. Figure 4In the example shown, the ground loop element 24 is arranged to pass between the first hot terminal 11 and the second hot terminal 21, so that a shielding effect can be obtained between the dipole antenna element 10 and the circularly polarized antenna element 20. Therefore, the dipole antenna element 10 and the circularly polarized antenna element 20 can be arranged close to each other to a certain extent. Figure 4 In the illustrated example, the first element 13 extends directly downward from the lower right corner of the first thermal terminal 11 .

[0047] In addition, the length of one side of the ground loop element 24 is adjusted, for example, based on twice the length of one of the third element 22 and the fourth element 23, so that the length of one side of the ground loop element 24 is shorter than twice the length of the third element 22 and the fourth element 23. By configuring the ground loop element 24 in this way, a reverse current is generated in the ground loop element 24 so that the currents generated in the third element 22 and the fourth element 23 cancel each other. As a result, the current generated in the third element 22 and the fourth element 23 is unlikely to enter the cable connected to the second hot terminal 21 and the ground terminal 12. That is, it is possible to obtain an effect substantially the same as that of the case where the circularly polarized antenna element 20 is grounded. Therefore, the composite antenna device of the present invention does not need to be grounded to the roof of a vehicle, etc., and the installability is improved.

[0048] According to such a structure, the impedance becomes low (for example, about 60Ω), so a balun for impedance adjustment is not required in the circularly polarized antenna element 20 of the composite antenna device of the present invention. Therefore, the module terminal 30 connected to the circularly polarized antenna element 20 of the composite antenna device of the present invention can be configured to be smaller, and the cost can also be reduced.

[0049] In the example shown in the figure, the ground loop element 24 is shown to be substantially square in shape, but the composite antenna device of the present invention is not limited thereto and may be rectangular or may have a curved shape such as a circle.

[0050] Next, use Figure 5 Another example of the composite antenna device of the present invention will be described. Figure 5 1 is a schematic top view for explaining another example of the composite antenna device of the present invention. Figure 1 The parts with the same reference numerals as those in the figure represent the same objects. In this example, the composite antenna device of the present invention further includes a second parasitic element 25. In addition, in the example shown in the figure, the dipole antenna element 10 includes Figure 3 An example of such a parasitic element 16 is shown, but the present invention is not limited thereto. Figure 1 As shown, the parasitic element 16 may not be provided. Figure 2 As shown, it can also be composed of a ring-shaped antenna element 15.

[0051] The second parasitic element 25 is arranged in the ground loop element 24. And, the second parasitic element 25 is arranged near the top of the third element 22 and the fourth element 23 in a capacitive coupling manner. In the example shown in the figure, the second parasitic element 25 is arranged with sides facing each other near the top in order to more strongly perform capacitive coupling with the third element 22. In addition, the second parasitic element 25 is arranged along the ground loop element 24. In addition, in the example shown in the figure, the second parasitic element 25 is arranged along three sides of the ground loop element 24 in consideration of design, but the present invention is not limited to this, and as long as it is arranged near the top of the third element 22 or the fourth element 23 in a capacitive coupling manner, it can also be arranged along only one side of the ground loop element 24.

[0052] Furthermore, the impedance can be adjusted by using the length of the portions where the second parasitic element 25 and the third element 22 are facing each other near their top ends or the distance between them.

[0053] In the circularly polarized antenna element 20 of the composite antenna device of the present invention, with such a configuration, it is possible to adjust the impedance, improve the gain, and improve the bandwidth.

[0054] According to such a structure, the composite antenna device of the present invention can improve the performance of the circularly polarized antenna element 20 while preventing the radiation efficiency of the dipole antenna element 10 from being reduced, so that both the dipole antenna element 10 and the circularly polarized antenna element 20 have good antenna characteristics. In addition, the first hot terminal 11, the second hot terminal 21, and the ground terminal 12 are concentrated on a straight line, so it is also easy to supply power.

[0055] Furthermore, the composite antenna device of the present invention is not limited to the above-described illustrated example, and various modifications can be made without departing from the spirit and scope of the present invention.

[0056] Description of Reference Numerals

[0057] 1. Membrane; 10. Dipole antenna element; 11. 1st hot terminal; 12. Ground terminal; 13. 1st element; 14. 2nd element; 15. Ring antenna element; 16. Parasitic element; 20. Circularly polarized antenna element; 21. 2nd hot terminal; 22. 3rd element; 23. 4th element; 24. Ground loop element; 25. 2nd parasitic element; 30. Module terminal.

Claims

1. A composite antenna device, which is a film-type composite antenna device for vehicle mounting, It is characterized in that The composite antenna device comprises: A dipole antenna element comprising: a first hot terminal, a ground terminal, a first element extending from the first hot terminal, and a second element extending from the ground terminal; and A circularly polarized antenna element comprises: a second hot terminal, which is arranged on a straight line connecting the first hot terminal and the ground terminal in a manner of being sandwiched between the first hot terminal and the ground terminal; a third element, which extends from the second hot terminal; and a fourth element, which extends from the ground terminal in a direction perpendicular to the third element.

2. The composite antenna device according to claim 1, It is characterized in that The dipole antenna element is a loop-shaped antenna element connecting the top end of a first element and the top end of a second element.

3. The composite antenna device according to claim 1, It is characterized in that The dipole antenna element has a parasitic element disposed near the tips of the first element and the second element in a capacitive coupling manner.

4. The composite antenna device according to any one of claims 1 to 3, It is characterized in that The first hot terminal, the second hot terminal and the ground terminal are covered by a module terminal including a transceiver.

5. The composite antenna device according to any one of claims 1 to 3, It is characterized in that The composite antenna device further includes a ground loop element extending from the ground terminal, passing between the first hot terminal and the second hot terminal, and returning to the ground terminal so as to surround the second hot terminal, the third element, and the fourth element.

6. The composite antenna device according to claim 5, It is characterized in that The ground loop element has sides extending parallel to the dipole antenna element.

7. The composite antenna device according to claim 5, It is characterized in that The ground loop element is substantially square in shape.

8. The composite antenna device according to claim 5, It is characterized in that The composite antenna device further includes a second parasitic element, which is disposed in the ground loop element and is disposed near the tips of the third element and the fourth element in a capacitively coupled manner.

9. The composite antenna device according to claim 8, It is characterized in that The second parasitic element has a side extending parallel to the ground loop element.

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