Vehicle antenna device

Abstract

To provide an antenna device for a vehicle, comprising a simple circuit construction for performing a plurality of types of signal processing for an antenna provided to a window glass for the vehicle that receives an electric wave of different frequency bands.SOLUTION: An antenna device 1 for a vehicle comprises: a glass plate 10; an antenna 20; and an amplifier module 30. The antenna 20 includes: a first antenna 20A which can receive an electric wave in a VHF band; and a second antenna 20B which can receive an electric wave in an UHF band. In the amplifier module 30, a first amplifier 30A for amplifying a signal of the electric wave received by the first antenna 20A and a second amplifier 30B for amplifying the signal of the electric wave received by the second antenna 20B are integrally assembled. The antenna 20 includes: one or two power supply parts 21; and an antenna element 22 that is extended from the power supply part(s) 21. The amplifier module 30 includes one or two conductive parts 31 electrically connected to the power supply part(s) 21.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle antenna device. [Background technology]

[0002] Conventionally, vehicle antenna devices mounted on vehicle window glass include antennas capable of receiving radio waves in various frequency bands, such as AM broadcast waves, FM broadcast waves, European standard DAB (Band III) broadcast waves, and terrestrial digital television broadcast waves. These antennas form, for example, a linear antenna pattern in the opening of the vehicle window glass and are connected to an amplifier circuit via a cable or the like connected to a power supply part of the antenna tuned to the frequency band of each broadcast wave.

[0003] When placing an antenna capable of receiving signals in multiple frequency bands in the opening of a vehicle window glass, for example, if the antenna includes one that receives radio waves in a low frequency band such as the VHF band (30 MHz to 300 MHz), such as FM broadcast waves (76 MHz to 108 MHz), the wavelength is longer than that of radio waves in a high frequency band such as the UHF band (300 MHz to 3 GHz), so it is necessary to secure an area in which to place an antenna pattern suitable for reception, i.e., to secure a wide opening in the vehicle window glass.

[0004] The following Patent Document 1 discloses that when an antenna for FM broadcast waves and an antenna for terrestrial digital television broadcast waves (DTV) coexist, a power supply unit (e.g., a monopole) for supplying power to the FM antenna and a power supply unit (particularly a dipole) for supplying power to the DTV antenna are provided on the vehicle window glass, and these power supply units are connected to a receiver via a transmission line (such as a coaxial cable) that supplies power. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 003928 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology disclosed in the above-mentioned Patent Document 1 requires electronic circuits including amplifiers and tuners suitable for each antenna to process signals received from antennas for broadcast waves of different frequency bands, such as an FM antenna and a DTV antenna, which tends to make the circuit configuration complicated.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a vehicle antenna device with a simple circuit configuration for performing signal processing for multiple types of antennas mounted on vehicle window glass that receive radio waves in different frequency bands. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention has the following configuration. [1] A vehicle antenna device comprising: a glass plate for a vehicle; an antenna provided on the glass plate; and an amplifier module that amplifies radio wave signals received by the antenna, wherein the antenna has a first antenna capable of receiving VHF band radio waves and a second antenna capable of receiving UHF band radio waves, the amplifier module integrally incorporates a first amplifier that amplifies the radio wave signals received by the first antenna and a second amplifier that amplifies the radio wave signals received by the second antenna, the antenna has one or two power feed units and an antenna element extending from the power feed units, and the amplifier module has one or two conductor units electrically connected to the power feed units.

[0009] [2] The vehicle antenna device described in [1], wherein the antenna has only a first power supply portion as the power supply portion, and the amplifier module has only a first conductor portion electrically connected to the first power supply portion as the conductor portion, and amplifies a signal received from the antenna via the first conductor portion.

[0010] [3] The vehicle antenna device described in [1], wherein the antenna has a first power supply portion and a second power supply portion as the power supply portion, the amplifier module has a first conductor portion electrically connected to the first power supply portion and a second conductor portion electrically connected to the second power supply portion as the conductor portion, the second power supply portion is electrically grounded, and the amplifier module amplifies a signal received from the antenna via the first conductor portion.

[0011] [4] The vehicle antenna device according to [3], wherein the first antenna and the second antenna are dipole antennas having the first feeding portion and the second feeding portion.

[0012] [5] A vehicle antenna device according to any one of [1] to [4], comprising: a signal processing device that processes the signal amplified by the amplifier module; and a transmission line that transmits the signal amplified by the amplifier module to the signal processing device, wherein the transmission line has an earth portion that is electrically connected to a vehicle on which the glass plate is installed.

[0013] [6] The vehicle antenna device described in [5], wherein the length of the transmission line from the amplifier module to the earth part is within 0.6×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lower limit frequency received by the first antenna to the upper limit frequency received by the second antenna.

[0014] [7] The vehicle antenna device described in [5] or [6], wherein the transmission line has a first transmission line that transmits the signal amplified by the first amplifier to the signal processing device, and a second transmission line that transmits the signal amplified by the second amplifier to the signal processing device.

[0015] [8] The vehicle antenna device according to [7], wherein the earth section is a common earth section that integrates a first earth section of the first transmission line and a second earth section of the second transmission line.

[0016] [9] The vehicle antenna device described in [5] or [6], wherein the transmission line transmits a signal in which both the signal amplified by the first amplifier and the signal amplified by the second amplifier are superimposed to the signal processing device.

[0017]

[10] The vehicle antenna device according to any one of [1] to [9], wherein the amplifier module has a conductive terminal as the conductor portion, and the conductive terminal is fixed to the power supply portion.

[0018]

[11] The vehicle antenna device according to

[10] , wherein the conductive terminal is a spring terminal that protrudes toward the glass plate, and the spring terminal is in elastic contact with the power supply portion.

[0019]

[12] The vehicle antenna device according to

[10] or

[11] , wherein the conductive terminal and the power supply portion are fixed with lead-free solder.

[0020]

[13] A vehicle antenna device described in any one of [1] to [9], wherein the amplifier module has an earth terminal and a connection wire as the conductor portion, the earth terminal is positioned at a position different from the glass plate and is electrically connected to the vehicle in which the glass plate is installed, and the connection wire is electrically connected to the power supply portion.

[0021]

[14] The vehicle antenna device described in

[13] , wherein the length of the connecting line is within 0.35×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lower limit frequency received by the first antenna to the upper limit frequency received by the second antenna.

[0022]

[15] The vehicle antenna device according to any one of [1] to

[14] , wherein the first antenna receives radio waves in the frequency band of FM broadcast waves.

[0023]

[16] The vehicle antenna device according to

[15] , wherein the first antenna further receives radio waves in the frequency band of AM broadcast waves.

[0024]

[17] The vehicle antenna device according to any one of [1] to

[16] , wherein the second antenna receives radio waves in the frequency band of terrestrial digital television broadcast waves.

[0025]

[18] The vehicle antenna device according to any one of [1] to

[17] , wherein the glass plate is a windshield, a rear glass, or a side glass. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a vehicle antenna device having a simple circuit configuration for performing signal processing for multiple types of antennas provided on a vehicle window glass that receive radio waves in different frequency bands. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view of an upper rear portion of a vehicle equipped with a vehicle antenna device according to a first embodiment of the present invention. [Figure 2] 1 is a configuration diagram of a vehicle antenna device according to a first embodiment of the present invention. [Figure 3] 1 is a circuit diagram of an amplifier module according to a first embodiment of the present invention. [Figure 4] 1 is a configuration diagram of a test device for a vehicle antenna device according to a first embodiment of the present invention. [Figure 5] 4 is a table summarizing test results of the vehicle antenna device according to the first embodiment of the present invention. [Figure 6] 5 is a graph showing changes in gain of FM horizontally polarized waves of the vehicle antenna device according to the first embodiment of the present invention. [Figure 7] 4 is a graph showing changes in gain of FM vertically polarized waves of the vehicle antenna device according to the first embodiment of the present invention. [Figure 8] FIG. 6 is a configuration diagram of a vehicle antenna device according to a second embodiment of the present invention. [Figure 9] FIG. 10 is a perspective view of the upper rear part of a vehicle equipped with a vehicle antenna device according to a third embodiment of the present invention. [Figure 10]FIG. 10 is a configuration diagram of a vehicle antenna device according to a third embodiment of the present invention. [Figure 11] FIG. 10 is a configuration diagram of a vehicle antenna device according to a fourth embodiment of the present invention. [Figure 12] FIG. 10 is a circuit diagram of an amplifier module according to a fourth embodiment of the present invention. [Figure 13] FIG. 10 is a circuit diagram of an amplifier module according to a fifth embodiment of the present invention. [Figure 14] FIG. 10 is a configuration diagram of a vehicle antenna device according to a sixth embodiment of the present invention. [Figure 15] FIG. 10 is a circuit diagram of an amplifier module according to a sixth embodiment of the present invention. [Figure 16] FIG. 10 is a configuration diagram showing a modified example of the vehicle antenna device according to the sixth embodiment of the present invention. [Figure 17] FIG. 13 is a configuration diagram showing another modified example of the vehicle antenna device according to the sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, a vehicle antenna device according to an embodiment of the present invention will be described in detail with reference to the drawings. For ease of understanding, the scale of each part in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up-down, left-right, and the like are allowed to have deviations to the extent that they do not impair the effects of the embodiment. The shape of the corners is not limited to right angles, and may be rounded in an arched shape. Parallel, right-angled, orthogonal, horizontal, and vertical may include substantially parallel, substantially right-angled, substantially orthogonal, substantially horizontal, and substantially vertical.

[0029] Furthermore, "~" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, " / " inserted between two frequency bands means a combination of receiving radio waves of different frequency bands. Furthermore, front, rear, left, right, and top and bottom refer to the front, rear, left, right, top and bottom of the vehicle on which the vehicle antenna device is installed.

[0030] [First embodiment] FIG. 1 is a perspective view of the upper rear part of a vehicle 100 equipped with a vehicle antenna device 1 according to a first embodiment of the present invention. 1, the vehicle antenna device 1 is illustrated as being attached to a rear window 11 and a back door 102 of a vehicle 100. The back door 102 is attached to the rear of a vehicle body 110 so as to be able to open and close. Note that the vehicle 100 equipped with the vehicle antenna device 1 is just one example, and the portion on which the vehicle antenna device 1 is mounted may include the rear window of a sedan-type vehicle that does not have an openable back door 102.

[0031] The vehicle 100 is equipped with a windshield (front glass) (not shown), a rear window 11, and side windows 12. The windshield and side windows 12 are attached to the vehicle body 110 side. The rear window 11 is attached to the back door 102 side. The vehicle body 110 is equipped with a roof 111 (roof portion) and a plurality of pillars 112 (pillar portions) that support the roof 111.

[0032] The back door 102 rotates up and down by means of hinges 113 attached to the rear of the roof 111. The left and right sides of the back door 102 are connected to two pillars 112 arranged at the rear of the vehicle body 110 via gas springs 114. The gas springs 114 assist in opening and closing the back door 102.

[0033] The vehicle antenna device 1 includes a glass plate 10 for the vehicle, an antenna 20 provided on the glass plate 10, and an amplifier module 30 that amplifies radio wave signals received by the antenna 20. The antenna 20 is provided on a rear window 11, which is one of the glass plates 10 for the vehicle. The antenna 20 is not limited to being provided on the rear window 11, and may also be provided on a side window 12 or a windshield (not shown), but unless otherwise specified, the following description will be given assuming that the antenna 20 is provided on the rear window.

[0034] The amplifier module 30 is connected to a signal processing device 60 (see FIG. 2 ), which will be described later, via a transmission line 40. The transmission line 40 is, for example, a coaxial cable, but a microstrip line, a strip line, a coplanar line, a slot line, etc. can also be used. Unless otherwise specified, the transmission line 40 will hereinafter be described as a coaxial cable. The transmission line 40 is routed to the vehicle body 110 side via a grommet 115 and connected to the signal processing device 60. The signal processing device 60 processes the signal amplified by the amplifier module 30 and outputs the signal to a speaker or a display (not shown) provided on the vehicle body 110 side.

[0035] FIG. 2 is a configuration diagram of a vehicle antenna device 1 according to a first embodiment of the present invention. As shown in FIG. 2, the vehicle antenna device 1 includes a glass plate 10 (rear glass 11), an antenna 20, an amplifier module 30, a transmission line 40, a grounding section 50, and a signal processing device 60.

[0036] Antenna 20 has one power supply portion 21 formed on glass plate 10 and antenna element 22 extending from power supply portion 21 along glass plate 10. In other words, antenna 20 is a monopole antenna having only one power supply portion, namely, first power supply portion 21a, as power supply portion 21. First power supply portion 21a is a planar conductor pattern. Note that the shape of first power supply portion 21a is not limited to a rectangle in plan view as shown in FIG. 2.

[0037] The antenna 20 has a first antenna element 22a extending from the first power supply portion 21a as the antenna element 22. The first antenna element 22a is a linear conductor pattern extending from the first power supply portion 21a. The shape of the first antenna element 22a is not limited to a linear shape, and may be a strip shape or a flat shape.

[0038] The first antenna element 22a is capable of receiving radio waves in a plurality of different frequency bands, and includes, for example, an antenna pattern capable of receiving radio waves in the VHF band (30 MHz to 300 MHz) and an antenna pattern capable of receiving radio waves in the UHF band (300 MHz to 3 GHz). Therefore, in this case, the antenna 20 has a first antenna 20A capable of receiving radio waves in the VHF band and a second antenna 20B capable of receiving radio waves in the UHF band.

[0039] The amplifier module 30 has one conductor 31 exposed on the glass plate 10. That is, the amplifier module 30 has only the first conductor 31a as the conductor 31, which is electrically connected to the first power supply 21a. The first conductor 31a is a conductive terminal fixed to the first power supply 21a. An example of the conductive terminal is a spring terminal that protrudes toward the glass plate 10. The spring terminal has a convex shape on the outside of the amplifier module 30 and is in elastic contact with the first power supply 21a. Note that the conductive terminal is not limited to a spring terminal and may be, for example, a conductor having any shape that does not undergo elastic deformation like a spring, as long as it can be electrically connected to the power supply 21.

[0040] The first conductor 31a shown in FIG. 2 is provided on the bottom surface of the rectangular box-shaped housing of the amplifier module 30, facing the glass plate 10. When the first conductor 31a is a spring terminal, the first conductor 31a and the first power supply 21a can be connected and fixed without using solder. Furthermore, the amplifier module 30 is preferably configured to be fixed to any part of the vehicle body 110 so that the first conductor 31a, which is a spring terminal, and the first power supply 21a can be stably connected without misalignment. The first conductor 31a and the first power supply 21a may be connected by solder, particularly lead-free solder for environmental reasons. The amplifier module 30 is mounted on the glass plate 10. The amplifier module 30 amplifies a signal received from the antenna 20 via the first conductor 31a.

[0041] The amplifier module 30 integrally incorporates a first amplifier 30A that amplifies the radio wave signal received by the first antenna 20A and a second amplifier 30B that amplifies the radio wave signal received by the second antenna 20B. Here, "integrally incorporated" means that the first amplifier 30A and the second amplifier 30B are contained in a single housing of the amplifier module 30.

[0042] FIG. 3 is a circuit diagram of an amplifier module 30 according to a first embodiment of the present invention. As shown in FIG. 3, the amplifier module 30 receives a signal from one first conductor portion 31a and outputs the signal from two output portions 32 (a first output portion 32a and a second output portion 32b).

[0043] The first output unit 32a outputs a signal in the frequency band (76 MHz to 108 MHz) of FM broadcast waves amplified by the first amplifier 30A, and the second output unit 32b outputs a signal in the frequency band (470 MHz to 710 MHz) of terrestrial digital television broadcast waves (DTV) amplified by the second amplifier 30B.

[0044] The first amplifier 30A has an FM band-pass filter circuit 71, an automatic gain control circuit 72, an FM amplifier circuit 73, an FM band-pass filter matching circuit 74, and a power supply noise filter 75. The FM band-pass filter circuit 71 passes only signals in the frequency band of FM broadcast waves contained in the signal from the first conductor portion 31a, and cuts off other frequency components.

[0045] The automatic gain control circuit 72 feeds back the peak signal level output from the FM amplifier circuit 73, thereby adjusting the gain so that it is within an appropriate range for the input signal level from the FM bandpass filter circuit 71. The FM amplifier circuit 73 amplifies the signal from the automatic gain control circuit 72, thereby compensating for distribution loss and cable loss and maintaining the signal level within the recommended level value.

[0046] The FM bandpass filter matching circuit 74 cuts out frequency components outside the frequency band of the FM broadcast wave contained in the signal amplified by the FM amplifier circuit 73, and obtains good amplification characteristics with little reflection loss by matching the output impedance of the FM amplifier circuit 73 to the impedance (e.g., 50Ω) of the first output part 32a. The power supply noise filter 75 prevents noise from other electronic devices installed in the vehicle 100 from being introduced into each circuit through the power supply.

[0047] The second amplifier 30B has a first DTV band-pass filter circuit 81, a DTV amplifier circuit 82, a matching circuit 83, a second DTV band-pass filter circuit 84, and a power supply noise filter 85. The first DTV band-pass filter circuit 81 passes only signals in the frequency band of DTV broadcast waves contained in the signal from the first conductor portion 31a, and cuts signal components in other frequency bands.

[0048] DTV amplifier circuit 82 compensates for distribution loss and cable loss and maintains the signal level within recommended levels by amplifying the signal from first DTV bandpass filter circuit 81. Matching circuit 83 matches the output impedance of DTV amplifier circuit 82 to the impedance of second output section 32b (e.g., 50Ω), thereby achieving good amplification characteristics with little return loss.

[0049] The second DTV bandpass filter circuit 84 cuts out frequency components outside the frequency band of the DTV broadcast waves that are contained in the signal output from the matching circuit 83 and amplified by the DTV amplifier circuit 82. The power supply noise filter 85 prevents noise from other electronic devices installed in the vehicle 100 from being mixed into each circuit through the power supply.

[0050] 2, the transmission line 40 transmits the signal amplified by the amplifier module 30 to the signal processing device 60. The transmission line 40 has a first transmission line 41 connected to the first output unit 32a and transmitting the signal amplified by the first amplifier 30A to the signal processing device 60, and a second transmission line 42 connected to the second output unit 32b and transmitting the signal amplified by the second amplifier 30B to the signal processing device 60.

[0051] As shown in Fig. 3, the transmission line 40 is a coaxial cable including an inner conductor 40a and an outer conductor 40b that covers the outside of the inner conductor 40a via an insulator. As shown in Fig. 1, the transmission line 40 is routed from the back door 102 to the vehicle body 110 side via a grommet 115 and connected to a signal processing device 60 provided on the vehicle body 110 side.

[0052] The outer conductor 40b of the transmission line 40 is connected to a metal part of the vehicle body 110 by a grounding unit 50. The grounding unit 50 is a midpoint ground terminal that electrically grounds the amplifier module 30 and the signal processing device 60. The grounding unit 50 is fixed to a metal part of the vehicle body 110, for example, by screwing. The grounding unit 50 has a first grounding unit 51 that connects the outer conductor 40b of the coaxial cable used as the first transmission line 41 to a metal part of the vehicle body 110, and a second grounding unit 52 that connects the outer conductor 40b of the coaxial cable used as the second transmission line 42 to a metal part of the vehicle body 110. Note that if a cable other than a coaxial cable is used for each transmission line 40, the ground potential of each transmission line 40 may be connected to a metal part of the vehicle body 110.

[0053] In the present embodiment, since the back door 102 is made of resin, the outer conductor 40b of the transmission line 40 routed to the vehicle body 110 side via the grommet 115 is electrically grounded by connecting it to a metal part of the vehicle body 110 via the earth part 50. The metal part of the vehicle body 110 to which the earth part 50 is connected is preferably, for example, a metal part of the roof 111 or a pillar 112. If the back door 102 is made of metal, the earth part 50 may be connected to a metal part of the back door 102. The first earth part 51 and the second earth part 52 correspond to midpoint earth terminals.

[0054] In the transmission line 40, the length L (see FIG. 4 described later) from the amplifier module 30 to the ground section 50 (midpoint ground terminal) is preferably within 0.6×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This can suppress a decrease in the gain of the antenna 20. Note that L is preferably within 0.4×k×λ, and more preferably 0.3×k×λ.

[0055] Fig. 4 is a configuration diagram of a test device for the vehicle antenna device 1 according to the first embodiment of the present invention. Fig. 5 is a table summarizing test results for the vehicle antenna device 1 according to the first embodiment of the present invention. As shown in Fig. 4, in this test, the length L from the amplifier module 30 to the earth part 50 in the transmission line 40 was changed, and the change in the gain of the antenna 20 was measured. As shown in Fig. 5, the combination of radio waves of different frequency bands received by the antenna 20 is an FM / DTV pattern.

[0056] The test results showed that in the case of FM / DTV, when the length L (the longest length [m] to the earth in Figure 5) from the amplifier module 30 to the earth section 50 (midpoint earth terminal) in the transmission line 40 was within 0.45 m, the decrease in gain of the antenna 20 could be suppressed.

[0057] For FM / DTV, the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B is 76 MHz to 710 MHz. The wavelength in air at the center frequency (393 MHz) is λ = 0.72. The wavelength shortening rate, calculated assuming the surrounding medium of a typical cable (air: k = 1), satisfies the following relationship: 0.6 × k × λ (wavelength of the center frequency: 0.76 m) ≦ length to the earth (midpoint earth terminal) (0.45 m). Specifically, when the maximum length to the earth [m] is 0.45 m and the coefficient is 0.590, the gain reduction suppression effect of the antenna 20 was achieved. Furthermore, when the maximum length to the earth [m] is 0.30 m and the coefficient is 0.393, the desirable gain reduction suppression effect of the antenna 20 was achieved. Furthermore, when the longest length [m] to the earth was 0.20 m and the coefficient at that time was 0.262, a more preferable effect of suppressing the decrease in gain of the antenna 20 was obtained.

[0058] Fig. 6 is a graph showing changes in gain of FM horizontally polarized waves in the vehicle antenna device 1 according to the first embodiment of the present invention. Fig. 7 is a graph showing changes in gain of FM vertically polarized waves in the vehicle antenna device 1 according to the first embodiment of the present invention. The vertical axis in Fig. 6 and Fig. 7 represents gain [dB], and the horizontal axis represents frequency [MHz]. Fig. 6 and Fig. 7 are supplementary tests for FM / DTV, and show changes in FM band gain when the length L from the amplifier module 30 to the earth section 50 (midpoint earth terminal) in the transmission line 40 is changed.

[0059] As shown in Figures 6 and 7, when L = 150 mm and L = 200 mm, a gain improvement of approximately the amplifier gain (8 dB) is observed compared to when there is no amplifier module 30 (no amplifier (reference)). Furthermore, when L = 400 mm, the gain begins to decrease slightly. Furthermore, when L = 500 mm, the gain begins to decrease slightly. Therefore, in the FM band, it is recommended that L ≦ 450 mm, i.e., L ≦ 0.6 × k × λ (k = 1, λ = 0.72).

[0060] As described above, the vehicle antenna device 1 of this embodiment includes a vehicle glass plate 10, an antenna 20 provided on the glass plate 10, and an amplifier module 30 that amplifies radio wave signals received by the antenna 20. The antenna 20 includes a first antenna 20A capable of receiving VHF radio waves and a second antenna 20B capable of receiving UHF radio waves. The amplifier module 30 includes a first amplifier 30A that amplifies the radio wave signals received by the first antenna 20A and a second amplifier 30B that amplifies the radio wave signals received by the second antenna 20B. The antenna 20 includes one or two power feeders 21 and an antenna element 22 extending from the power feeders 21. The amplifier module 30 includes one or two conductors 31 electrically connected to the power feeders 21. This allows the first amplifier 30A and the second amplifier 30B to be integrated into a single amplifier module 30, resulting in a compact design. Therefore, it is possible to provide a vehicle antenna device 1 having a simple circuit configuration for performing signal processing for a plurality of types of antennas 20 provided on vehicle window glasses that receive radio waves in different frequency bands.

[0061] In addition, in the vehicle antenna device 1 of this embodiment, the antenna 20 is a so-called monopole antenna having only the first power supply portion 21a as the power supply portion 21, and the amplifier module 30 has only the first conductor portion 31a electrically connected to the first power supply portion 21a as the conductor portion 31, and amplifies the signal received from the antenna 20 via the first conductor portion 31a.

[0062] The vehicle antenna device 1 of this embodiment also includes a signal processing device 60 that processes the signal amplified by the amplifier module 30, and a transmission line 40 that transmits the signal amplified by the amplifier module 30 to the signal processing device 60, and the transmission line 40 has a grounding part 50 that is electrically connected to the vehicle 100 on which the glass plate 10 is provided. This makes it possible to suppress a decrease in the gain of the antenna 20.

[0063] In the vehicle antenna device 1 of this embodiment, the length L of the transmission line 40 from the amplifier module 30 to the grounding section 50 (midpoint grounding terminal) is within 0.6×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This further suppresses the reduction in gain of the antenna 20.

[0064] Furthermore, in the vehicle antenna device 1 of this embodiment, the transmission line 40 has a first transmission line 41 that transmits the signal amplified by the first amplifier 30A to the signal processing device 60, and a second transmission line 42 that transmits the signal amplified by the second amplifier 30B to the signal processing device 60. This allows signals of different frequency bands to be transmitted to the signal processing device 60 via different lines.

[0065] Furthermore, in the vehicle antenna device 1 of this embodiment, the amplifier module 30 has a conductive terminal as the conductor portion 31, and the conductive terminal is fixed to the power supply portion 21. As a result, the amplifier module 30 is disposed on the glass plate 10, making it easier to ensure installation space for the amplifier module 30.

[0066] In addition, in the vehicle antenna device 1 of this embodiment, spring terminals can be used as a means for connecting the conductive terminal and the power supply portion 21 without using solder, and further, as a conductive terminal different from the spring terminal, lead-free solder can be used to connect and fix the terminal in consideration of the environment.

[0067] Furthermore, in the vehicle antenna device 1 of this embodiment, the conductive terminal is a spring terminal that protrudes toward the glass plate 10, and the spring terminal is in elastic contact with the power supply part 21. This makes it possible to reduce vibrations that the amplifier module 30 arranged on the glass plate 10 receives.

[0068] In the vehicle antenna device 1 of this embodiment, the first antenna 20A may receive radio waves in the frequency band of FM broadcast waves. Furthermore, in the vehicle antenna device 1 of this embodiment, the second antenna 20B may receive radio waves in the frequency band of terrestrial digital television broadcast waves.

[0069] In the vehicle antenna device 1 of this embodiment, the glass plate 10 can be applied to a windshield, rear glass 11, or side glass 12, but is not limited to these and can also be applied to a roof glass, front bench glass, rear quarter glass, etc.

[0070] Second Embodiment Fig. 8 is a configuration diagram of a vehicle antenna device 1 according to a second embodiment of the present invention. In Fig. 8, the same components as those in the above-described embodiment are denoted by the same reference numerals. As shown in Figure 8, the vehicle antenna device 1 of the second embodiment differs from the above-mentioned embodiments in that the earth section 50 has a common earth section 53 (midpoint earth terminal) that integrates the first earth section 51 (see Figure 2) of the first transmission line 41 and the second earth section 52 (see Figure 2) of the second transmission line 42.

[0071] The common ground part 53 connects the outer conductor 40b of the first transmission line 41 and the outer conductor 40b of the second transmission line 42 together to a metal part of the vehicle body 110. In the transmission line 40, the length D from the amplifier module 30 to the common ground part 53 is preferably within 0.6×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This prevents a decrease in the gain of the first antenna 20A and the second antenna 20B. Note that D is preferably within 0.4×k×λ, and more preferably 0.3×k×λ.

[0072] The signal processing device 60 includes an FM band bias tee 61 that processes the signal from the first transmission line 41, and a DTV combining unit bias tee 62 that processes the signal from the second transmission line 42. The DTV combining unit bias tee 62 is connected to the signal lines 40c of each channel included in the internal conductor 40a of the second transmission line 42.

[0073] As described above, the vehicle antenna device 1 of the second embodiment has, as the grounding section 50 (midpoint grounding terminal), the common grounding section 53 that integrates the first grounding section 51 of the first transmission line 41 and the second grounding section 52 of the second transmission line 42. This allows the first transmission line 41 and the second transmission line 42 to be bundled together for midpoint grounding, thereby reducing the number of components of the grounding section 50 and making it more compact.

[0074] Third Embodiment Fig. 9 is a perspective view of the upper rear of a vehicle 100 equipped with a vehicle antenna device 1 according to a third embodiment of the present invention. Fig. 10 is a configuration diagram of a vehicle antenna device 1 according to the third embodiment of the present invention. In Figs. 9 and 10, the same components as those in the above-described embodiments are denoted by the same reference numerals. As shown in FIG. 9, the vehicle antenna device 1 of the third embodiment differs from the above-described embodiments in that the amplifier module 30 is disposed at a position different from the glass plate 10.

[0075] The amplifier module 30 is attached, for example, to (the interior side of) the roof 111 of the vehicle body 110. The amplifier module 30 may also be attached to a pillar 112 or other part (such as a hatchback) of the vehicle body 110. The amplifier module 30 has a connection line 34 as the conductor portion 31. The connection line 34 is routed from the vehicle body 110 to the back door 102 side through a grommet 115 and connected to the power supply portion 21 of the antenna 20.

[0076] 10, the antenna 20 has a connection terminal 24 connected to the first power supply part 21a. A connector 36 provided at the tip of a connection line 34 extending from the amplifier module 30 is connected to the connection terminal 24. In addition to the connection line 34, the amplifier module 30 has a ground terminal 35 as the conductor part 31. The ground terminal 35 protrudes from a part of the housing of the amplifier module 30 and is connected to a metal part of the vehicle body 110.

[0077] The length E of the connecting line 34 is preferably within 0.35×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This numerical range was derived from tests similar to those shown in FIGS. 4 to 7 above. This makes it possible to suppress a decrease in the gain of the antenna 20. Note that E is preferably within 0.26×k×λ, and more preferably 0.2×k×λ.

[0078] As described above, in the vehicle antenna device 1 of the third embodiment, the amplifier module 30 has the ground terminal 35 and the connection wire 34 as the conductor portion 31, the ground terminal 35 is disposed at a position different from the glass plate 10 and is electrically connected to the vehicle 100 on which the glass plate 10 is provided, and the connection wire 34 is electrically connected to the power supply portion 21. This increases the versatility of the layout of the amplifier module 30.

[0079] In the vehicle antenna device 1 of this embodiment, the length of the connection line 34 is within 0.35×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of the frequency band from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This makes it possible to suppress a decrease in the gain of the antenna 20.

[0080] [Fourth embodiment] Fig. 11 is a configuration diagram of a vehicle antenna device 1 according to a fourth embodiment of the present invention. Fig. 12 is a circuit diagram of an amplifier module 30 according to the fourth embodiment of the present invention. In Fig. 11 and Fig. 12, the same components as those in the above-described embodiments are denoted by the same reference numerals. As shown in FIG. 11, the vehicle antenna device 1 of the fourth embodiment differs from the above-described embodiments in that the transmission line 40 transmits to the signal processing device 60 a signal in which both the signal amplified by the first amplifier 30A and the signal amplified by the second amplifier 30B are superimposed.

[0081] The vehicle antenna device 1 has only one transmission line 40. As shown in Fig. 12, the amplifier module 30 receives a signal from one first conductor portion 31a and outputs the signal from one output portion 32. The output portion 32 outputs a signal in which a signal in the frequency band (76 MHz to 108 MHz) of FM broadcast waves amplified by the first amplifier 30A and a signal in the frequency band (470 MHz to 710 MHz) of terrestrial digital television broadcast waves (DTV) amplified by the second amplifier 30B are superimposed.

[0082] 12, the first amplifier 30A has an FM band-pass filter circuit 71, an automatic gain control circuit 72, an FM amplifier circuit 73, an FM band-pass filter matching circuit 74, and a power supply noise filter 75. The second amplifier 30B has a first DTV band-pass filter circuit 81, a DTV amplifier circuit 82, a matching circuit 83, and a second DTV band-pass filter circuit 84. In the fourth embodiment, the power supply noise filter 75 of the first amplifier 30A is also used as the power supply noise filter of the second amplifier 30B.

[0083] 11, signal processing device 60 has an FM band bias tee 61, a DTV combining unit bias tee 62, and a branching circuit 63. Branching circuit 63 processes signals from transmission line 40, branching FM band signals to FM band bias tee 61 and DTV band signals to DTV combining unit bias tee 62. DTV combining unit bias tee 62 is connected to signal lines 64 that output the combined signals of each channel.

[0084] As described above, in the vehicle antenna device 1 of the fourth embodiment, the transmission line 40 transmits a signal in which both the signal amplified by the first amplifier 30A and the signal amplified by the second amplifier 30B are superimposed to the signal processing device 60. This allows for only one transmission line 40 and only one earth part 50 to be required, thereby reducing the number of parts of the vehicle antenna device 1 and simplifying the device.

[0085] Fifth Embodiment Fig. 13 is a circuit diagram of an amplifier module 30 according to a fifth embodiment of the present invention. In Fig. 13, the same components as those in the above-described embodiments are denoted by the same reference numerals. As shown in FIG. 13, the vehicle antenna device 1 of the fifth embodiment differs from the above-described embodiments in that the first antenna 20A further receives radio waves in the frequency band (522 kHz to 1710 kHz) of AM broadcast waves.

[0086] The first amplifier 30A has an AM band-pass filter circuit 76, an AM amplifier circuit 77, a matching circuit 78, and an FM blocking circuit 79 in addition to the above-mentioned FM band-pass filter circuit 71, automatic gain control circuit 72, FM amplifier circuit 73, FM band-pass filter matching circuit 74, and power supply noise filter 75.

[0087] The AM bandpass filter circuit 76 passes only the signal in the frequency band of the AM broadcast wave contained in the signal from the first conductor portion 31a, and cuts off other frequency components. The AM amplifier circuit 77 amplifies the signal from the AM bandpass filter circuit 76 to compensate for distribution loss and cable loss and maintain the signal level within the recommended level value.

[0088] The matching circuit 78 matches the output impedance of the AM amplifier circuit 77 to the impedance (e.g., 50Ω) of the first output port 32a, thereby achieving good amplification characteristics with little return loss. The FM blocking circuit 79 blocks the output signal from the FM bandpass filter matching circuit 74 from flowing into the matching circuit 78 (AM side). The signal processing device 60 that receives the signal from the first output part 32a via the first transmission line 41 may preferably include a bias tee for FM / AM bands that can process signals in not only the FM band but also the AM band.

[0089] As described above, in the vehicle antenna device 1 of the fifth embodiment, the first antenna 20A further receives radio waves in the frequency band of AM broadcast waves. This allows reception of not only radio waves in the frequency band of FM broadcast waves but also radio waves in the frequency band of AM broadcast waves.

[0090] Sixth Embodiment Fig. 14 is a configuration diagram of a vehicle antenna device 1 according to a sixth embodiment of the present invention. Fig. 15 is a circuit diagram of an amplifier module 30 according to the sixth embodiment of the present invention. In Fig. 14 and Fig. 15, the same components as those in the above-mentioned embodiments are denoted by the same reference numerals. 14, the vehicle antenna device 1 of the sixth embodiment differs from the above-described embodiments in that the antenna 20 has a first power supply portion 21a and a second power supply portion 21b as the power supply portion 21. Although not shown in FIG. 14, the vehicle antenna device 1 includes a transmission line 40, a ground portion 50, and a signal processing device 60 in addition to the glass plate 10, the antenna 20, and the amplifier module 30.

[0091] The antenna 20 is a dipole antenna having two power feed portions: a first power feed portion 21a and a second power feed portion 21b. The first power feed portion 21a and the second power feed portion 21b are arranged side by side with a fixed interval between them. The second power feed portion 21b is a planar conductor pattern. The shapes of the first power feed portion 21a and the second power feed portion 21b are not limited to a rectangular shape in plan view as shown in FIG. 14. The second power feed portion 21b is electrically grounded.

[0092] The antenna 20 has a second antenna element 22b extending from the second power supply portion 21b as the antenna element 22. The second antenna element 22b is a linear conductor pattern extending from the second power supply portion 21b. The shape of the second antenna element 22b is not limited to a linear shape, and may be a strip shape or a flat shape.

[0093] The amplifier module 30 has two conductors 31 exposed on the glass plate 10. That is, the amplifier module 30 has, as the conductors 31, a first conductor 31a electrically connected to the second power supply portion 21b and a second conductor 31b electrically connected to the second power supply portion 21b. The second conductor 31b is a conductive terminal fixed to the second power supply portion 21b. The conductive terminal can be, for example, a spring terminal protruding toward the glass plate 10. The spring terminal has a convex shape on the outside of the amplifier module 30 and is in elastic contact with the first power supply portion 21a and the second power supply portion 21b, respectively. Note that, in this embodiment, the conductive terminal is not limited to a spring terminal and may be, for example, a conductor having any shape that does not undergo elastic deformation like a spring, as long as it can be electrically connected to the first power supply portion 21a and the second power supply portion 21b.

[0094] As shown in FIG. 14 , the first conductor 31a and the second conductor 31b are provided on the bottom surface of the rectangular box-shaped housing of the amplifier module 30, facing the glass plate 10. When the first conductor 31a and the second conductor 31b are spring terminals, the first conductor 31a and the first power supply 21a, and the second conductor 31b and the second power supply 21b, can be connected and fixed without using solder. In this embodiment, too, the amplifier module is preferably fixed to any part of the vehicle body, and the first conductor 31a and the first power supply 21a, which are spring terminals, and the second conductor 31b and the second power supply 21b can be stably connected without misalignment. Note that the first conductor 31a and the first power supply 21a, and the second conductor 31b and the second power supply 21b may be connected and fixed by solder, particularly lead-free solder for environmental considerations. The amplifier module 30 is attached to the glass plate 10. The amplifier module 30 is electrically grounded via the second conductor portion 31b, and amplifies the signal received from the first conductor portion 31a.

[0095] 15, the amplifier module 30 receives a signal from the first conductor portion 31a (HOT side) of the two conductor portions 31 and outputs a signal from two output portions 32 (the first output portion 32a and the second output portion 32b). The amplifier module 30 is electrically grounded by the second conductor portion 31b (earth side) of the two conductor portions 31.

[0096] As described above, the first amplifier 30A has an FM band-pass filter circuit 71, an automatic gain control circuit 72, an FM amplifier circuit 73, an FM band-pass filter matching circuit 74, a power supply noise filter 75, an AM band-pass filter circuit 76, an AM amplifier circuit 77, a matching circuit 78, and an FM blocking circuit 79.

[0097] As described above, the second amplifier 30B has a first DTV band-pass filter circuit 81, a DTV amplifier circuit 82, a matching circuit 83, a second DTV band-pass filter circuit 84, and a power supply noise filter 85. Description of each circuit will be omitted to avoid redundancy. The circuit shown in Fig. 15 is an example, and a configuration in which a second conductor portion 31b (earth side) is added to the circuits shown in Figs. 3 and 12 above may also be used.

[0098] As described above, in the vehicle antenna device 1 of the sixth embodiment, the antenna 20 has, as the power supply section 21, the first power supply section 21a and the second power supply section 21b, and the amplifier module 30 has, as the conductor section 31, the first conductor section 31a electrically connected to the first power supply section 21a and the second conductor section 31b electrically connected to the second power supply section 21b, the second power supply section 21b being electrically grounded, and the amplifier module 30 amplifies the signal received from the antenna 20 via the first conductor section 31a.

[0099] In the vehicle antenna device 1 of the sixth embodiment, the first antenna 20A and the second antenna 20B are so-called dipole antennas having a first power feeding portion 21a and a second power feeding portion 21b.

[0100] <Variations> Fig. 16 is a configuration diagram showing a modified example of the vehicle antenna device 1 according to the sixth embodiment of the present invention. In Fig. 16, the same components as those in the above-described embodiments are denoted by the same reference numerals. In the vehicle antenna device 1 (dipole) of the sixth embodiment, the amplifier module 30 may be arranged at a position different from the glass plate 10, as in the vehicle antenna device 1 (monopole) of the third embodiment shown in Figure 10 described above.

[0101] The amplifier module 30 is attached, for example, to (the interior side of) the roof 111 of the vehicle body 110. The amplifier module 30 may also be attached to a pillar 112 or other part (such as a hatchback) of the vehicle body 110. The amplifier module 30 has a first connection line 34a and a second connection line 34b as the conductor portion 31. The first connection line 34a and the second connection line 34b are not coaxial cables but are general electric wires in which automotive electric wires are covered with vinyl (insulator).

[0102] The antenna 20 has connection terminals 24 at the first power feed portion 21a and the second power feed portion 21b. The first connection line 34a has a connector 36 connected to the first power feed portion 21a via the connection terminals 24. The second connection line 34b has a connector 36 connected to the second power feed portion 21b via the connection terminals 24.

[0103] The amplifier module 30 includes a ground terminal 35 as a conductor portion 31 in addition to the first connection line 34a and the second connection line 34b. The ground terminal 35 protrudes from a portion of the housing of the amplifier module 30 and is connected to a metal portion of the vehicle body 110. The lengths of the first connection line 34a and the second connection line 34b (corresponding to E shown in FIG. 10 ) are preferably within 0.35×k×λ, where λ is the wavelength in air and k is the wavelength shortening rate of the surrounding medium at the center frequency of a frequency band ranging from the lowest frequency received by the first antenna 20A to the highest frequency received by the second antenna 20B. This prevents a decrease in the gain of the first antenna 20A and the second antenna 20B. E is preferably within 0.26×k×λ, and more preferably 0.2×k×λ.

[0104] Fig. 17 is a configuration diagram showing another modified example of the vehicle antenna device 1 according to the sixth embodiment of the present invention. In Fig. 17, the same components as those in the above-described embodiments are denoted by the same reference numerals. Furthermore, in another modification of the sixth embodiment, the bipolar amplifier module 30 may be connected to the first power supply portion 21a and the second power supply portion 21b by a single connection line 34 (coaxial cable).

[0105] A coaxial connector 25 is attached to the glass plate 10. The coaxial connector 25 has two connection terminals 26 and is connected to the first power feed portion 21a and the second power feed portion 21b. The connection line 34 has an inner conductor and an outer conductor that covers the outside of the inner conductor via an insulator. The inner conductor of the connection line 34 is connected to the first power feed portion 21a via the coaxial connector 25. The outer conductor of the connection line 34 is connected to the second power feed portion 21b via the coaxial connector 25. This allows only one connection line 34 to be required, making the vehicle antenna device 1 more compact.

[0106] Although the vehicle antenna device according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be freely modified within the scope of the present invention. For example, some or all of the embodiments may be combined. Furthermore, the shape and arrangement of the antenna are not limited to the embodiment and may be modified within the scope of the present invention. [Explanation of symbols]

[0107] 1 Vehicle antenna device 10 Glass Plate 11 Rear window 12 Side glass 20 Antenna 20A First Antenna 20B Second antenna 21 Power supply unit 21a First power supply 21b Second power supply section 22 Antenna Element 30 Amplifier Module 30A 1st amplifier 30B Second Amplifier 31 Conductor 31a First conductor part 31b Second conductor part 34 connecting wire 35 Ground terminal 40 Transmission Line 41 First transmission line 42 Second transmission line 50 Earth section 51 First Earth Section 52 Second Earth Section 53 Common ground part 60 Signal Processing Device 100 vehicles

Claims

1. Glass plates for vehicles; an antenna provided on the glass plate; an amplifier module that amplifies the radio wave signal received by the antenna; a signal processing device that processes the signal amplified by the amplifier module; a transmission line for transmitting the signal amplified by the amplifier module to the signal processing device, The antenna includes a first antenna capable of receiving radio waves in the VHF band and a second antenna capable of receiving radio waves in the UHF band, a first amplifier that amplifies the radio wave signal received by the first antenna and a second amplifier that amplifies the radio wave signal received by the second antenna are integrally incorporated in the amplifier module; The antenna has one or two feed points and an antenna element extending from the feed points, the amplifier module has one or two conductor parts electrically connected to the power supply part, the transmission line has a ground portion electrically connected to a vehicle on which the glass plate is provided, The transmission line transmits to the signal processing device a signal in which both the signal amplified by the first amplifier and the signal amplified by the second amplifier are superimposed.

2. The first amplifier includes a power supply noise filter; 2. The vehicle antenna device according to claim 1, wherein the power supply noise filter is also used as a power supply noise filter for the second amplifier.

3. A vehicle antenna device as described in claim 1 or 2, wherein the amplifier module is mounted on the glass plate.

4. the antenna has only a first feed portion as the feed portion, 3. The vehicle antenna device according to claim 1, wherein the amplifier module has only a first conductor portion electrically connected to the first power supply portion as the conductor portion, and amplifies a signal received from the antenna via the first conductor portion.

5. the antenna has a first feed portion and a second feed portion as the feed portion, the amplifier module includes, as the conductor portion, a first conductor portion electrically connected to the first power supply portion and a second conductor portion electrically connected to the second power supply portion; the second power supply unit is electrically grounded, The vehicle antenna device according to claim 1 or 2, wherein the amplifier module amplifies a signal received from the antenna via the first conductor portion.

6. 6. The vehicle antenna device according to claim 5, wherein the first antenna and the second antenna are dipole antennas having the first feeding portion and the second feeding portion.

7. 7. The vehicle antenna device according to claim 6, wherein a length of the transmission line from the amplifier module to the earth portion is within 0.6×k×λ, where λ is a wavelength in air and k is a wavelength shortening rate of a surrounding medium at a center frequency of a frequency band ranging from a lower limit frequency received by the first antenna to an upper limit frequency received by the second antenna.

8. the amplifier module has a conductive terminal as the conductor portion, The vehicle antenna device according to claim 1 or 2, wherein the conductive terminal is fixed to the power supply portion.

9. the conductive terminal is a spring terminal that protrudes toward the glass plate; 9. The vehicle antenna device according to claim 8, wherein the spring terminal is in elastic contact with the power supply portion.

10. 9. The vehicle antenna device according to claim 8, wherein the conductive terminal and the power supply portion are fixed together with lead-free solder.

11. the amplifier module has a ground terminal and a connection line as the conductor portion, the ground terminal is disposed at a position different from the glass plate and is electrically connected to a vehicle in which the glass plate is installed; The vehicle antenna device according to claim 1 , wherein the connection line is electrically connected to the power supply portion.

12. 12. The vehicle antenna device according to claim 11, wherein a length of the connecting line is within 0.35 × k × λ, where λ is a wavelength in air and k is a wavelength shortening rate of a surrounding medium at a center frequency of a frequency band ranging from a lower limit frequency received by the first antenna to an upper limit frequency received by the second antenna.

13. 3. The vehicle antenna device according to claim 1, wherein the first antenna receives radio waves in an FM broadcast wave frequency band.

14. 14. The vehicle antenna device according to claim 13, wherein the first antenna further receives radio waves in a frequency band for AM broadcast waves.

15. The vehicle antenna device according to claim 1 or 2, wherein the second antenna receives radio waves in a frequency band for terrestrial digital television broadcast waves.

16. 3. The vehicle antenna device according to claim 1, wherein the glass plate is a windshield, a rear glass, or a side glass.

Images