Low profile composite antenna device

Abstract

Provided is a low-profile composite antenna device in which the antenna receiving characteristics of a patch antenna are improved even if the housing is low-profile and has a restriction in the height direction. The low-profile composite antenna device is composed of a base (10), a first antenna (20), and a second antenna (30). The first antenna (20) has a patch electrode (21) that can receive signals of a first frequency band. The second antenna (30) that can receive signals of a second frequency band has a top load portion (31) as a capacitive element, the top load portion (31) is disposed in the vicinity of the patch electrode (21) in such a manner as not to cover the patch electrode (21) of the first antenna (20) when viewed from above and the patch electrode (21) is located on an extension axis of the longitudinal direction of the top load portion (31), and has at least one stub (32) that electrically divides the longitudinal direction of the top load portion (31) into front and back, so that the top load portion (31) also functions as a waveguide of the first antenna (20).

Description

Technical Field

[0001] This invention relates to a low-profile composite antenna device, and more particularly to a low-profile composite antenna device capable of receiving signals from multiple frequency bands for use in vehicles. Background Technology

[0002] As vehicle antenna devices, those capable of receiving AM and FM radio broadcasts are commonly used. Vehicle antenna devices utilize rod antennas, membrane antennas, glass antennas, etc., and recently, small and low-profile antenna devices, such as so-called shark fin antennas, have also emerged. Rod antennas, for example, are constructed with an antenna length that is one-quarter the wavelength of the FM band. Furthermore, in vehicle antenna devices, the height protruding from the roof is limited by external protrusions; therefore, helical antennas, which are constructed by winding the antenna element into a spiral shape to achieve a shorter length, are also available. However, in the AM band, this antenna length becomes quite short relative to the wavelength, resulting in a significant decrease in receiving sensitivity. Therefore, by mounting the top load portion of the metal body to the open end of the antenna element to form a capacitive antenna with electrostatic capacitance, a low-profile shark fin type antenna device designed for AM / FM broadcasts has also been developed.

[0003] Furthermore, as a low-profile composite antenna device that combines a patch antenna with such a low-profile antenna device to further receive signals from multiple frequency bands, there exists, for example, Patent Document 1. Patent Document 1 describes a device in which the width dimension of a capacitor plate, which functions as an AM / FM element, is set to approximately 1 / 4 wavelength or less of the receiving frequency of the patch antenna disposed below the AM / FM element, and is configured to be zigzag-shaped extending in the length direction. The polarized wave component of the capacitor plate in the received wave of the patch antenna is orthogonal to the line disposed approximately parallel to the width direction, thus minimizing its impact on the antenna characteristics of the patch antenna.

[0004] However, the low-profile composite antenna device disclosed in Patent Document 1 has a complex shape due to its zigzag capacitor plate. In addition, it is prone to deformation during assembly, making assembly difficult and manufacturing inexpensive.

[0005] As a solution to this problem, there is also a patent document 2 from the same applicant as the applicant of this application. Patent document 2 is a low-profile composite antenna device, which has: a patch antenna; and an AM / FM element configured to cover the patch antenna, having a top load portion that also functions as a waveguide for the patch antenna and has a conductive surface state.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-034226

[0009] Patent Document 2: Japanese Patent Application Publication No. 2018-121143 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] In recent years, further miniaturization has been desired in vehicle antenna devices. For top-mounted sections like those in Patent Documents 1 and 2, maintaining a certain height from the base is necessary to improve performance. However, when reducing the height of the top-mounted section for even greater miniaturization, capacitive coupling with the patch antenna can occur, potentially degrading the antenna reception characteristics of AM / FM components.

[0012] Furthermore, GNSS (Global Navigation Satellite System) to date uses L1 signal carriers. However, in recent years, multi-band GNSS has gradually emerged and is increasingly using L5 signals. Since the frequency bands of L1 and L5 signals are separate, patch antennas designed to handle both frequencies are generally used. Specifically, a dual-frequency patch antenna is, for example, a stacked patch antenna formed by layering an L1 signal patch antenna on top of an L5 signal patch antenna, requiring a certain height. On the other hand, for top load sections like those in Patent Documents 1 and 2, as described above, to improve performance, a certain height from the base is required. However, it is difficult to house the top load section on top of the stacked patch antenna in a way that covers the already tall stacked patch antenna. Therefore, the development of a low-profile composite antenna device that improves the antenna receiving characteristics of the patch antenna even with a lower housing that is limited in the height direction is desirable.

[0013] In view of this reality, the present invention aims to provide a low-profile composite antenna device that improves the antenna reception characteristics of the patch antenna even with a low-profile housing that is limited in the height direction.

[0014] Solution for solving the problem

[0015] To achieve the aforementioned objective of the present invention, the low-profile composite antenna device of the present invention comprises the following components: a base fixed to a vehicle; a first antenna mounted on the base and having a patch electrode capable of receiving signals in a first frequency band; and a second antenna capable of receiving signals in a second frequency band lower than the first frequency band, having a top load portion as a capacitor element arranged at a distance from the base in the height direction, the top load portion being arranged near the patch electrode in such a way that it does not cover the patch electrode of the first antenna when viewed from above and the patch electrode is located on the extended axis of the longitudinal direction of the top load portion, and having at least one stub electrically dividing the longitudinal direction of the top load portion into front and rear sections, so that the top load portion also functions as a waveguide for the first antenna.

[0016] The second antenna can be an antenna in the following manner: the top load portion is composed of a ridge portion extending in the longitudinal direction of the top load portion and side portions extending from both sides of the ridge portion. The stub includes: two first slits that extend parallel to the middle of the other side portion from the lower end of one side portion through the ridge portion; and a second slit that extends parallel to the first slit from the lower end of the other side portion to the middle between the two first slits.

[0017] Alternatively, the second antenna may be an antenna in the following manner: the top load portion is composed of a ridge portion extending in the longitudinal direction of the top load portion and side portions extending from both sides of the ridge portion, and the stub includes: a wide slit extending from the lower end of one side portion toward the ridge portion; two first slits extending parallel from the two ends of the deepest part of the wide slit to the middle of the other side portion; and a second slit extending parallel to the first slit from the lower end of the other side portion to the middle between the two first slits.

[0018] In addition, the second antenna can be an antenna in which the stub is positioned at a predetermined distance from the end of the patch electrode side in the longitudinal direction of the top load part or from the end of the top load part on the side opposite to the patch electrode side, in a manner that optimizes the signal reception characteristics of the first antenna.

[0019] In addition, the second antenna may be an antenna in which the predetermined distance between the stub and the end of the patch electrode side in the longitudinal direction of the top load portion or the end of the side opposite to the patch electrode side is 2 to 3 times the size of the patch electrode of the first antenna.

[0020] In addition, the first antenna can be constructed from an antenna used in the L1 band of GNSS.

[0021] Alternatively, the first antenna may consist of an antenna for the L1 band and an antenna for the L5 band of GNSS.

[0022] Alternatively, the second antenna may also have a coil connected at one end to the top load portion, so that the top load portion functions as an AM antenna, and the top load portion and the coil function as an FM antenna.

[0023] The effects of the invention

[0024] The low-profile composite antenna device of the present invention has the following advantages: by arranging the top load portion in a manner that does not cover the patch antenna when viewed from above, the antenna reception characteristics of the patch antenna can be improved even in a low-profile housing with limitations in the height direction. Furthermore, it has the advantage that the patch antenna is not placed at the bottom of the top load portion, thus, as a result, the performance of the top load portion is also improved. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the low-profile composite antenna device of the present invention.

[0026] Figure 2 This is a schematic diagram illustrating the low-profile composite antenna device of the present invention.

[0027] Figure 3 This is an unfolded view of the top load portion of the low-profile composite antenna device of the present invention before bending.

[0028] Figure 4 This is a gain variation chart of the first antenna used to illustrate the effect of the stub of the low-profile composite antenna device of the present invention.

[0029] Figure 5 This is a gain variation chart of the first antenna used to illustrate other effects of the stub of the low-profile composite antenna device of the present invention.

[0030] Figure 6 This is an unfolded view of the top load portion of the low-profile composite antenna device of the present invention before bending. Detailed Implementation

[0031] The following describes a method for carrying out the invention, together with the illustrated examples. Figure 1 This is a schematic diagram illustrating the low-profile composite antenna device of the present invention. Figure 1 (a) is a top view. Figure 1(b) is a partial sectional view. The low-profile composite antenna device of the present invention can receive signals from multiple frequency bands used in vehicles. As shown in the figure, it mainly consists of a base 10, a first antenna 20, and a second antenna 30. Furthermore, these components are configured to be covered by an antenna radome 1. The antenna radome 1 has internal space for accommodating components, circuits, etc., and defines the shape of the low-profile composite antenna device. The low-profile composite antenna device of the present invention can be configured, for example, as a composite antenna combining a capacitor antenna capable of receiving AM band signals and a patch antenna for GNSS, SDARS, etc.

[0032] The base 10 is fixed to the vehicle. Specifically, the base 10 may be a resin base, for example, made of an insulator such as resin, or a metal base, made of a conductor such as metal. Alternatively, the base 10 may be a composite base of resin and metal. A threaded protrusion 11 is provided on the base 10. The threaded protrusion 11 is inserted into a hole provided in the roof of the vehicle, etc., and a nut is used from inside the vehicle to clamp the roof, etc., thereby fixing the base 10 to the vehicle. Cables connecting the vehicle interior and the antenna device pass through the threaded protrusion 11. Furthermore, the base 10 is configured to be covered by an antenna cover 1. The internal space is sealed by fitting the base 10 into the antenna cover 1.

[0033] The first antenna 20 is mounted on the base 10. Furthermore, the first antenna 20 has a patch electrode 21 capable of receiving signals in the first frequency band. The first antenna 20 can be, for example, a dielectric patch antenna 22 using circularly polarized waves, such as ceramic. For example, it can be a patch antenna used in GNSS applications such as GPS and GLONASS. Alternatively, it can be an XM antenna used in SDARS.

[0034] The second antenna 30 can receive signals from a second frequency band lower than the first frequency band. Specifically, the second antenna 30 can be, for example, an AM antenna using the MF band as its resonant frequency. The second antenna 30 has a top load portion 31 that functions as a capacitor element. That is, the top load portion 31 is made of a conductor, allowing it to function as a capacitive antenna with electrostatic capacitance. The top load portion 31 is arranged with a gap relative to the base 10 in the height direction. The top load portion 31 is arranged near the patch electrode 21 such that it does not cover the patch electrode 21 of the first antenna 20 when viewed from above, and the patch electrode 21 is located on the extended axis of the longitudinal direction of the top load portion 31. That is, the top load portion 31 is not configured to cover the first antenna 20. Furthermore, the top load portion 31 has at least one short stub 32 that electrically divides the longitudinal direction of the top load portion 31 into front and rear sections, so that it also functions as a waveguide for the first antenna 20. The stub 32 is formed by a folded pattern, which is composed of a plurality of slits 33 alternately arranged in the top load portion 31 in such a way that the current flows in directions that cancel each other out.

[0035] In the above-described example, the first antenna 20 is shown as being composed of a single patch antenna. However, the present invention is not limited thereto. In the low-profile composite antenna device of the present invention, the top load portion 31 can be configured such that it does not cover the patch electrode 21 of the first antenna 20 when viewed from above, thus alleviating the limitation in the height direction of the first antenna 20. Therefore, the first antenna 20 can also be a stacked patch antenna with height.

[0036] Figure 2 This is a schematic diagram illustrating another example of the low-profile composite antenna device of the present invention. Figure 2 (a) is a top view. Figure 2 (b) is a partial sectional view. In the figure, labels are attached to... Figure 1 The same reference numerals in the accompanying drawings denote the same objects. This example illustrates that the first antenna 20 is constructed from a stacked patch antenna. Specifically, the first antenna 20 is composed of an L1 signal patch antenna 23 corresponding to the frequency band of the L1 signal carrier used in multi-GNSS and an L5 signal patch antenna 24 corresponding to the frequency band of the L5 signal carrier. The first antenna 20 in the figure example represents an antenna formed by stacking the L1 signal patch antenna 23 on top of the L5 signal patch antenna 24. A stacked patch antenna refers to an antenna formed by stacking multiple patch antennas with different frequency bands. For example, the L1 patch antenna 23 has patch electrodes 25 capable of receiving signals in the L1 frequency band. Additionally, the L5 patch antenna 24 has patch electrodes 26 capable of receiving signals in the L5 frequency band. Such a patch antenna can be, for example, a dielectric patch antenna using ceramic or other materials that uses circularly polarized waves. It can be an antenna formed by stacking these materials, or an antenna formed by combining dielectric patch antennas and gap-type patch antennas and stacking them together.

[0037] Furthermore, the first antenna 20 is not limited to an antenna formed by stacking multiple patch antennas when configured to cope with multiple bands. It can be an antenna formed by arranging multiple patch antennas on a plane, or it can be a double-loop patch antenna.

[0038] In this invention, the top load portion 31 of the second antenna 30 is configured, for example, as a capacitive antenna in the MF band (AM band) to receive signals from the second band, but the invention is not limited thereto. In the low-profile composite antenna device of the present invention, the second antenna 30 may also be configured as an AM / FM antenna. That is, as... Figure 2As shown, the second antenna 30 may also have a coil 40 connected to the top load portion 31. One end of the coil 40 is connected to the top load portion 31, and the other end is connected to the power supply portion. Thus, the second antenna 30 can be configured such that the top load portion 31 becomes a capacitor antenna and functions as an AM antenna, and it can also be configured such that the top load portion 31 and the coil 40 become a capacitor antenna and function as an FM antenna with a shortened element length.

[0039] use Figure 3 The details of the top load portion of the low-profile composite antenna device of the present invention will be explained. Figure 3 This is a unfolded view of the top load portion of the low-profile composite antenna device of the present invention before bending. In the figure, [the following text is incomplete and likely refers to a different topic:] ...and... Figure 1 The same reference numerals in the accompanying drawings denote the same object. Specifically, the second antenna 30 indicates an antenna with a streamlined shape formed by a ridge portion 31a extending in the longitudinal direction of the top load portion 31 and side portions 31b, 31b' extending from both sides of the ridge portion 31a. The top load portion 31 can be formed by bending in a shape corresponding to the shape of the radome 1, such as a shark fin shape. For such a top load portion 31, the stub 32 includes: two first slits 33a that extend parallel to each other from the lower end of one side portion 31b through the ridge portion 31a to the middle of the other side portion 31b'; and a second slit 33b that extends parallel to each other from the lower end of the other side portion 31b' to the middle of the two first slits 33a. By placing such a short stub 32 in the middle of the top load portion 31, the longitudinal direction of the top load portion 31 can be electrically divided into front and back.

[0040] The top load portion 31 can be easily formed, for example, by cutting it from a flat plate into a predetermined shape as shown in the example, or by bending it into a peak using sheet metal processing. Alternatively, notches, fins, or the like can be used to form the screw fixing portion.

[0041] The stub 32 of the top load portion 31 is positioned at a predetermined distance D from the end of the patch electrodes 25 and 26 in the longitudinal direction of the top load portion 31, in a manner that optimizes the signal reception characteristics of the first antenna 20. In other words, the position of the stub 32 is adjusted so that the top load portion 31 functions as a waveguide relative to the first antenna 20. The position of the stub 32 is determined to improve the antenna reception characteristics, such as the antenna gain of the first antenna 20. For example, if the first antenna 20 is a patch antenna for GNSS, the distance D from the end of the patch electrodes 25 and 26 to the stub 32 is 2 to 3 times the electrode size of the patch electrodes 25 and 26 of the first antenna 20. That is, in the attached figures, the distance D from the left end (top of the top load portion) of the top load portion 31 to the stub 32 is 2 to 3 times the electrode size of the patch electrodes 25 and 26. More specifically, for example, if the longitudinal dimension of the top load portion 31 is 100mm, and the electrode size of the patch electrode 25 for the L1 signal is 21mm on one side, and the electrode size of the patch electrode 26 for the L5 signal is 28mm on one side, then the distance D from the top of the top load portion 31 to the stub 32 can be about 67mm.

[0042] Furthermore, if the first antenna 20 is a patch antenna operating at a higher frequency band, such as an MX antenna for SDARS, a stub 32 can be positioned at a predetermined distance D' from the end of the top load portion 31 on the side opposite to the patch electrode side (the rear end of the top load portion). That is, the distance D' from the rear end of the top load portion 31 to the stub 32 should be 2 to 3 times the electrode size of the patch electrode. In this way, the placement of the stub 32 on the second antenna 30 can be appropriately adjusted according to the frequency band of the first antenna 20 to improve the antenna reception characteristics of the first antenna 20.

[0043] Here, the effect of the stub of the low-profile composite antenna device of the present invention will be explained. Figure 4 The graph shows the gain variation of the first antenna, used to illustrate the effect of the stub in the low-profile composite antenna device of the present invention. The horizontal axis represents frequency, and the vertical axis represents the gain of the first antenna. In the graph, the solid line represents... Figure 2 The graph shows the gain variation of the first antenna 20 in the low-profile composite antenna device of the present invention. Additionally, as a comparative example, the graph shows the gain variation of the first antenna when the second antenna 30 is not used, indicated by dashed lines. As shown, it can be seen that when the second antenna 30 of the present invention, which is composed of a top load portion 31 with a stub 32, is used, the gain is improved in the frequency band of either the L1 or L5 signal compared to the case where it is not used.

[0044] In addition, Figure 5 The graph shows the gain variation of the first antenna, used to illustrate other effects of the stub in the low-profile composite antenna device of the present invention. The horizontal axis represents frequency, and the vertical axis represents the gain of the first antenna. Figure 5 (a) is a graph showing the gain change of the first antenna in the case where the distance between the first antenna and the second antenna is changed in the low-profile composite antenna device of the present invention. Figure 5 (b) is a graph showing the gain variation of the stacked patch antenna when the distance between the top load portion without the stub and the stacked patch antenna is changed as a comparative example. Furthermore, the distance between the first antenna and the second antenna is... Figure 3 The symbol "D" indicates the antenna configuration. As shown in the figure, in the case of the low-profile composite antenna device of the present invention, due to the presence of the stub 32, the second antenna 30 also functions as a waveguide. Therefore, the gain variation is minimal regardless of whether the first antenna 20 and the second antenna 30 are brought closer or further apart. That is, it can be seen that the configuration of the first antenna 20 and the second antenna 30 has a high degree of freedom. On the other hand, in the case where the top load portion without the stub is not used, the gain variation increases with distance, and the further away the antenna is, the higher the gain. That is, in the absence of the stub, the closer the antennas are, the worse the antenna reception characteristics of the stacked patch antenna become. Therefore, it can be seen that the configuration has a low degree of freedom. In addition, regarding the achievable gain, it can also be seen that the achievable gain of the present invention is generally higher compared to the comparative example.

[0045] Thus, in the low-profile composite antenna device of the present invention, the top load portion 31 of the second antenna 30 can be configured in a manner that does not cover the first antenna 20 when viewed from above, while being close to the first antenna 20. As a result, even with a low-profile housing that is limited in the height direction, the antenna reception characteristics of the first antenna 20 can be improved.

[0046] Furthermore, in the low-profile composite antenna device of the present invention, the first antenna 20, which is a patch antenna, is not positioned below the top load portion 31 of the second antenna 30. Therefore, the metal body such as the patch electrode of the first antenna 20 is not positioned near the lower part of the top load portion 31. Consequently, there is no concern about the coupling of the top load portion 31 relative to the metal body, which improves the antenna reception characteristics of the second antenna 30. In addition, the height of the top load portion 31 of the second antenna 30 can be suppressed, thus allowing for a lower profile.

[0047] Among them, in the above-mentioned figure example, the following example is shown: the stub 32 of the second antenna 30 extends from the side surface portion 31b on one side through the ridge line portion 31a to the side surface portion 31b' on the other side. However, the present invention is not limited thereto, and the stub 32 can electrically divide the longitudinal direction of the top load portion 31 into front and back in a manner that also functions as a waveguide of the first antenna 20. For example, it may also be that the stub 32 is only arranged on one side surface portion, and the other side surface portion is composed of a wide slit. Hereinafter, use Figure 6 will be described in detail.

[0048] Figure 6 is an unfolded view before bending of an example of another stub of the top load portion of the low-profile composite antenna device of the present invention. In the figure, the parts marked with the same reference numerals as Figure 1 represent the same thing. As shown in the figure, the top load portion 31 is composed of a ridge line portion 31a and side surface portions 31b, 31b', and the stub 32 is composed of a wide slit 33c, two first slits 33a, and a second slit 33b. The top load portion 31 is composed of a planar plate-like body before bending. It is cut out from the planar plate-like body in a predetermined shape as shown in the figure and bent into a peak fold at a predetermined position to form the top load portion 31.

[0049] Among them, the wide slit 33c of the stub 32 extends from the lower end of the side surface portion 31b on one side toward the ridge line portion 31a. The wide slit 33c is not for canceling out the direction of the current, but is a slit having a certain width that can prevent the front and back of the top load portion 31 from being strongly combined. And the two first slits 33a extend parallel from both ends of the deepest part of the wide slit 33c to the middle of the side surface portion 31b' on the other side. In addition, the second slit 33b extends parallel to the first slit 33a from the lower end of the side surface portion 31b' on the other side to the middle between the two first slits 33a. That is, for example, the slits in which the direction of the current of the stub 32 flows in a direction of mutual cancellation may also extend only to one side surface portion.

[0050] Thus, the stub 32 of the low-profile composite antenna device of the present invention does not need to electrically completely divide the longitudinal direction of the top load portion 31 into front and back, and can also be composed in combination with the wide slit 33c as long as it functions as a waveguide of the first antenna 20.

[0051] Moreover, the top load portion 31 showing the above-mentioned figure example is an example of a top load portion having a streamline shape such as a shark fin shape. However, the present invention is not limited thereto, and it may also be a planar plate-like conductor. That is, it may also be a top load portion in which a stub for dividing the longitudinal direction of the planar plate-like body arranged in the horizontal direction and the vertical direction into front and back is arranged at a predetermined position.

[0052] Furthermore, the low-profile composite antenna device of the present invention is not limited to the examples shown in the figures above, and various modifications can be made without departing from the spirit of the present invention.

[0053] Explanation of reference numerals in the attached figures

[0054] 1. Radome; 10. Base; 11. Protrusion; 20. First antenna; 21, 25, 26. Patch electrode; 22. Dielectric patch antenna; 23. Patch antenna for L1 signal; 24. Patch antenna for L5 signal; 30. Second antenna; 31. Top load section; 31a. Ridge section; 31b. Side section; 32. Short stub; 33. Slit; 33a. First slit; 33b. Second slit; 33c. Wide slit; 40. Coil.

Claims

1. A low-profile composite antenna device, characterized in that it is capable of receiving signals from multiple frequency bands used in vehicles, and is further characterized in that... This low-profile composite antenna device features: The base, which is fixed to the vehicle; The first antenna, which is mounted on the base, has patch electrodes capable of receiving signals in the first frequency band; as well as The second antenna, which is capable of receiving signals in a second frequency band lower than the first frequency band, has a top load portion that serves as a capacitor element and is arranged at intervals relative to the base in the height direction. The top load portion integrally includes a ridge portion extending in the longitudinal direction of the top load portion and side portions extending from both sides of the ridge portion. The top load portion is arranged near the patch electrode in such a way that it does not cover the patch electrode of the first antenna when viewed from above and the patch electrode is located on the extended axis of the longitudinal direction of the top load portion. Furthermore, it has at least one stub that electrically divides the longitudinal direction of the top load portion into front and back sections, so that the top load portion also functions as a waveguide for the first antenna.

2. The low-profile composite antenna device according to claim 1, characterized in that, For the second antenna The stub includes: two first slits extending parallel to each other from the lower end of the side portion of one side through the ridge portion to the middle of the side portion of the other side; and a second slit extending parallel to each other from the lower end of the side portion of the other side to the middle of the two first slits.

3. The low-profile composite antenna device according to claim 1, characterized in that, For the second antenna The stub includes: a wide slit extending from the lower end of one side portion toward the ridge portion; two first slits extending parallel to each other from the deepest ends of the wide slit to the middle of the other side portion; and a second slit extending parallel to the first slits from the lower end of the other side portion to the middle of the two first slits.

4. The low-profile composite antenna device according to any one of claims 1 to 3, characterized in that, For the second antenna, the stub is positioned at a predetermined distance from the end of the patch electrode side in the longitudinal direction of the top load portion or from the end of the top load portion on the side opposite to the patch electrode side, in a manner that optimizes the signal reception characteristics of the first antenna.

5. The low-profile composite antenna device according to claim 4, characterized in that, For the second antenna, the predetermined distance between the stub and the end of the patch electrode side in the longitudinal direction of the configured top load portion or the end on the side opposite to the patch electrode side is 2 to 3 times the patch electrode size of the first antenna.

6. The low-profile composite antenna device according to any one of claims 1 to 3, characterized in that, The first antenna is composed of an antenna for the L1 band of GNSS.

7. The low-profile composite antenna device according to any one of claims 1 to 3, characterized in that, The first antenna consists of an antenna for the L1 band and an antenna for the L5 band of GNSS.

8. The low-profile composite antenna device according to any one of claims 1 to 3, characterized in that, The second antenna also has a coil connected at one end to the top load portion, configured such that the top load portion functions as an AM antenna, and the top load portion and the coil function as an FM antenna.

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