Antenna device

Abstract

The present invention provides an antenna device that includes multiple antennas in a common housing, can suppress the decrease in antenna gain and achieve miniaturization. The antenna device (1) includes a TEL antenna (2) and a capacitive load element (3) in a common housing. The capacitive load element (3) is located above the TEL antenna (2). The length of the capacitive load element (3) is a natural multiple of 1 / 2 of the wavelength of the PCS band. The TEL antenna (2) is arranged to avoid the maximum voltage point of the standing wave of the PCS band generated by the capacitive load element (3).

Description

[0001] This application is a divisional application of the application with the application date of January 23, 2017, application number 201780005280.7, and invention name "antenna device". Technical Field

[0002] The present invention relates to an antenna device including two or more antennas in a common housing. Background Art

[0003] In recent years, in-vehicle antenna devices called shark fin antennas have been developed. In addition to broadcast receiving antennas such as AM / FM antennas, in-vehicle antenna devices are also being equipped with information communication antennas such as TEL antennas (for example, Patent Document 1 below).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2012-124714 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] If multiple antennas are installed in a limited space within a housing, the distance between the antennas cannot be sufficiently maintained, resulting in a decrease in antenna gain. On the other hand, increasing the distance between the antennas within the housing will increase the size of the housing, preventing miniaturization.

[0009] The present invention has been made in recognition of such a situation, and an object of the present invention is to provide an antenna device that includes a plurality of antennas in a common housing, can suppress a decrease in antenna gain, and can be downsized.

[0010] Solutions to Problems

[0011] One aspect of the present invention is an antenna device comprising a first antenna and a second antenna disposed within a common housing, the second antenna being plate-shaped and positioned above the first antenna, and the first antenna being positioned to avoid a point where the voltage of a standing wave generated by the second antenna in the frequency band of the first antenna reaches a maximum.

[0012] Alternatively, the first antenna may be disposed or extended within a range where a horizontal distance from a point where a voltage of the standing wave generated by the second antenna is minimum is within 1 / 8 of the wavelength of the standing wave.

[0013] Alternatively, the second antenna may include a first plate-shaped portion located above the first antenna, the first antenna may be located below a central portion of the first plate-shaped portion, and a length of the first plate-shaped portion may be an odd multiple of 1 / 2 of a wavelength of a frequency band of the first antenna.

[0014] Alternatively, the second antenna may include a first plate-shaped portion and a second plate-shaped portion, the first plate-shaped portion being located above the first antenna, and the second plate-shaped portion being electrically connected to the first plate-shaped portion via a filter portion that cuts off a frequency band of the first antenna.

[0015] The second antenna may include a first plate-shaped portion and a second plate-shaped portion, the first plate-shaped portion is located above the first antenna, and the second plate-shaped portion is electrically connected to the first plate-shaped portion via a fold line.

[0016] The first plate-shaped portion and the second plate-shaped portion may be arranged spaced apart from each other in the front-rear direction.

[0017] At least a portion of the second antenna located above the first antenna may be divided in the left-right direction.

[0018] The antenna device may include a helical element electrically connected to the second antenna.

[0019] The spiral element may be spiral-shaped and rotate in an elliptical shape when viewed from the direction of its own winding axis.

[0020] The antenna device may include a base that forms a housing space for the first antenna and the second antenna together with the housing.

[0021] The first antenna has a portion substantially perpendicular to the base.

[0022] Alternatively, the first antenna may be a TEL antenna, a TV antenna, a keyless entry antenna, an inter-vehicle communication antenna, or a WiFi antenna, and the second antenna may be an AM / FM antenna or a DAB receiving antenna.

[0023] The antenna device may include a helical element electrically connected to the second antenna, and the helical element may be arranged offset from a left-right center of a housing that holds the second antenna.

[0024] The winding axis of the spiral element may be inclined with respect to the vertical direction.

[0025] The helical element and the second antenna may not overlap in vertical direction.

[0026] The antenna device may include a holder that holds the helical element, and the holder may hold the helical element from an outer peripheral side or an inner peripheral side.

[0027] The stent may include a groove for holding the spiral element.

[0028] Alternatively, the base body may have a step on the lower surface.

[0029] The helical element may include a first helical element and a second helical element grounded via a filter unit that cuts off a frequency band of the first antenna.

[0030] The antenna device may include a conductor leaf spring that sandwiches the first antenna, and a portion of the first antenna sandwiched by the conductor leaf spring or the conductor leaf spring may include a protrusion.

[0031] The antenna device may include a third antenna provided in the housing, and an upper portion of the third antenna may be covered by a passive element.

[0032] The antenna device may include a second filter unit between the first helical element and an amplifier that amplifies a frequency of the second antenna, and the second filter unit may increase impedance of a TEL band.

[0033] One side and the other side of the second antenna divided in the left-right direction may be connected in the left-right direction.

[0034] The first antenna may extend upward from between one side and the other side of the second antenna divided in the left-right direction.

[0035] It should be noted that any combination of the above-mentioned constituent elements and any configuration in which the expression of the present invention is converted into a method, a system, or the like are also effective as aspects of the present invention.

[0036] Effects of the Invention

[0037] According to the present invention, it is possible to provide an antenna device that includes a plurality of antennas in a common housing and can suppress a decrease in antenna gain and achieve miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the antenna device 1 according to the first embodiment of the present invention.

[0039] Figure 2 This is a characteristic diagram based on simulation showing the relationship between frequency and average gain of the TEL antenna 2 of the antenna device 1 (single-dot chain line) and the relationship between frequency and average gain of the TEL antenna 2 alone (without the capacitive load element 3) (solid line).

[0040] Figure 3 This is a characteristic diagram based on simulation, showing the relationship between the total length (length L in the front-to-back direction) of the capacitive load element 3 and the average gain of the TEL antenna 2 at 1900 MHz when the TEL antenna 2 is arranged directly below the center position of the capacitive load element 3 in the front-to-back direction in the antenna device 1.

[0041] Figure 4 This is a characteristic diagram based on simulation, showing the relationship between the front-to-back distance x from the front end of the capacitive load element 3 to the front-to-back center position of the TEL antenna 2 and the average gain of the TEL antenna 2 at 1900 MHz, when the front-to-back length L of the capacitive load element 3 in the antenna device 1 is set to λ / 2.

[0042] Figure 5 This is a characteristic diagram based on simulation, showing the relationship between the front-to-back distance x from the front end of the capacitive load element 3 to the front-to-back center position of the TEL antenna 2 and the average gain of the TEL antenna 2 at 1900 MHz, when the front-to-back length L of the capacitive load element 3 in the antenna device 1 is set to λ.

[0043] Figure 6 It is a schematic diagram of an antenna device 1A according to a second embodiment of the present invention.

[0044] Figure 7 It is an exploded perspective view of the antenna device 1A.

[0045] Figure 8 Yes Figure 7 An enlarged front cross-sectional view of the periphery of the fitting portion between the tongue portion 3 c of the capacitance load element 3 and the groove portion 6 a of the inner case 6 .

[0046] Figure 9 This is an enlarged side sectional view showing the periphery of the fitting portion when the tongue portion 3 c is provided at the rear end portion of the capacitance load element 3 and is fitted into the groove portion 6 a of the inner case 6 .

[0047] Figure 10 (A)~ Figure 10 (F) is a perspective view showing the assembly process of the spiral element 5, the bracket 7 and the TEL antenna substrate 4.

[0048] Figure 11 (A)~ Figure 11 (C) is a schematic plan view showing the relative positional relationship between the TEL antenna 2 and the helical element 5 in each case where the winding shape of the helical element 5 is a circle, an ellipse long in the left-right direction, and an ellipse long in the front-back direction.

[0049] Figure 12 It is an enlarged cross-sectional view showing a state in which the conductor leaf springs 9 a and 9 b hold the TEL antenna substrate 4 .

[0050] Figure 13 It is a right side view of the antenna device 1A.

[0051] Figure 14 It is a right side cross-sectional view of the antenna device 1A.

[0052] Figure 15 yes Figure 14 Magnified front view.

[0053] Figure 16 This is a connection circuit diagram of the antenna device 1A (Part 1).

[0054] Figure 17 This is a connection circuit diagram of the antenna device 1A (part 2).

[0055] Figure 18 It is a schematic diagram of an antenna device 1B according to a third embodiment of the present invention.

[0056] Figure 19 This is a characteristic diagram based on simulation that shows the relationship between the frequency and average gain of the TEL antenna 2 of the antenna device 1A according to embodiment 2 and the antenna device 1B according to embodiment 3 (dashed line and single-dot chain line), and the relationship between the frequency and average gain of the TEL antenna 2 alone (when there is no capacitive load element 3) (solid line).

[0057] Figure 20 This is a characteristic diagram based on actual measurement showing the relationship between the frequency and the average gain of the TEL antenna 2 in each case where the capacitance load element 3 is divided front-to-back into the first plate-shaped portion 3a and the second plate-shaped portion 3b and when it is not divided front-to-back.

[0058] Figure 21 Schematic diagram of the antenna device of Comparative Example 1.

[0059] Figure 22 Schematic diagram of an antenna device according to Comparative Example 2.

[0060] Figure 23 This is a characteristic diagram based on simulation that shows the relationship between the frequency and average gain of the TEL antenna 2 of the antenna devices of Comparative Examples 1 and 2 (dashed line and single-dot chain line) and the relationship between the frequency and average gain of the TEL antenna 2 alone (when there is no capacitive load element 3) (solid line).

[0061] Figure 24 This is a characteristic diagram based on simulation showing the relationship between the distance from the capacitive load element 3 (inter-antenna distance) and the average gain in the TEL antenna 2 of the comparative example.

[0062] Figure 25 It is a perspective view of an antenna device 1C according to a fourth embodiment of the present invention.

[0063] Figure 26 is Figure 25 The three-dimensional diagram of the inner shell 6 is omitted.

[0064] Figure 27 3 : is a characteristic diagram based on simulation showing the relationship between the frequency and the average gain in the FM band of the AM / FM antenna in each case where the capacitance load element 3 has the notch portion 3 d and when the capacitance load element 3 does not have the notch.

[0065] Figure 28 It is a front cross-sectional view of an antenna device 1D according to a fifth embodiment of the present invention.

[0066] Figure 29 This is a characteristic diagram based on simulation showing the relationship between the frequency and average gain of the FM band of the AM / FM antenna when the capacitance load element 3 is divided into the left plate-shaped portion 3e and the right plate-shaped portion 3f and when it is not divided into the left plate-shaped portion 3e and the right plate-shaped portion 3f. DETAILED DESCRIPTION

[0067] The following describes in detail preferred embodiments of the present invention with reference to the accompanying drawings. It should be noted that identical or equivalent components and members shown in the various drawings are denoted by the same reference numerals, and duplicate descriptions are omitted as appropriate. Furthermore, the embodiments are illustrative rather than limiting of the invention, and not all features or combinations thereof described in the embodiments are necessarily essential features of the invention.

[0068] (Implementation 1)

[0069] Reference Figures 1 to 5 , describing embodiment 1 of the present invention. Figure 1 Schematic diagram of the antenna device 1 according to the first embodiment. Figure 1 , the front and back, up and down, left and right directions of the antenna device 1 are defined. The direction perpendicular to the up and down direction is the horizontal direction. It should be noted that the front and back direction is the length direction of the antenna device 1, and the left and right direction is the width direction of the antenna device 1. Moreover, the front is the forward direction when the antenna device 1 is installed on the vehicle, and the left and right directions are determined based on the state of observing the forward direction, that is, the front. The antenna device 1 is for vehicle-mounted use and is installed on the roof of the vehicle, etc. The antenna device 1 is equipped with an AM / FM antenna in a housing (not shown), and the AM / FM antenna has a TEL antenna 2 as a first antenna, a capacitive load element 3 as a second antenna, and a helical element (AM / FM coil) 5. The capacitive load element 3 and the helical element 5 enable AM / FM broadcast reception.

[0070] The TEL (Telephone) antenna 2 is, for example, a conductor pattern on a substrate. The frequency band of the TEL antenna 2 is the PCS (Personal Communications Service) band. The PCS band has a frequency range of 1850 to 1990 MHz, but 1900 MHz, the center frequency of the PCS band, is used as a representative value here. The TEL antenna 2 exists within a plane parallel to the front-to-back and up-to-down directions. The TEL antenna 2 is preferably a wideband antenna capable of transmitting and receiving in the AMPS (Advanced Mobile Phone System) / PCS band. The AMPS band has a frequency range of 824 to 894 MHz.

[0071] The capacitive load element 3 is a plate-shaped component formed by processing a metal plate (conductor plate) such as stainless steel. The capacitive load element 3 is located above the TEL antenna 2. In the case where the TEL antenna 2 is located below a position that is an odd multiple of 1 / 4 of the wavelength λ from the end of the capacitive load element 3, the front-to-back length L of the capacitive load element 3 is preferably a natural number multiple of 1 / 2 of the wavelength λ. Here, the wavelength λ is the wavelength of the PCS band (TEL band). In the case where the TEL antenna 2 is located below the central part of the capacitive load element 3, the front-to-back length L of the capacitive load element 3 is preferably an odd multiple of 1 / 2 of the wavelength λ. Figure 1 In the example, the front-to-back length L of the capacitance load element 3 is L=λ / 2. Figure 1 In the figure, the current distribution of the PCS frequency band generated by the capacitive load element 3 is represented by the dotted line. The position where the current distribution is the smallest, that is, Figure 1 In the example, the front and rear ends of the capacitive load element 3 are the points of maximum voltage. Moreover, the position where the current distribution is the largest, i.e. Figure 1 In the example, the center position of the capacitive loading element 3 in the front-to-back direction is the point of minimum voltage. It should be noted that if the TEL antenna 2 is a wideband antenna capable of transmitting and receiving AMPS and PCS bands, the capacitive loading element 3 has an electrical length that is non-resonant with respect to the AMPS band. It should be noted that if the capacitive loading element 3 has an electrical length that is non-resonant with respect to the AMPS band (for example, approximately λ / 4 or less of the AMPS band), then, as long as transmission and reception of the AMPS band is concerned, no matter where the TEL antenna 2 is positioned below the capacitive loading element 3, there will be no adverse effects due to electrical coupling with the capacitive loading element 3.

[0072] The distance x in the front-to-back direction from the front end of the capacitive load element 3 to the front-to-back center of the TEL antenna 2 is determined to avoid the maximum voltage point of the standing wave in the PCS frequency band generated by the capacitive load element 3. Preferably, the front-to-back center of the TEL antenna 2 is located at the minimum voltage point of the capacitive load element 3 or within a range of λ / 8 from the minimum voltage point, or the TEL antenna 2 extends at the minimum voltage point of the capacitive load element 3 or within a range of λ / 8 from the minimum voltage point.

[0073] Figure 2 This is a characteristic diagram based on simulation showing the relationship between frequency and average gain of the TEL antenna 2 of the antenna device 1 (single-dot chain line) and the relationship between frequency and average gain of the TEL antenna 2 alone (without the capacitive load element 3) (solid line). Figure 2 The characteristic shown by the single-dot chain line is the characteristic when the TEL antenna 2 is arranged so that its center position in the front-back direction is located directly below the voltage minimum point of the capacitive load element 3. Figure 2 As shown, although the TEL antenna 2 of the antenna device 1 is located below the capacitive load element 3, substantially the same antenna gain characteristics as those in the case of the TEL antenna 2 alone can be obtained.

[0074] Figure 3 This is a characteristic diagram based on simulation showing the relationship between the total length (length L in the front-to-back direction) of the capacitive load element 3 and the average gain of the TEL antenna 2 at 1900 MHz when the TEL antenna 2 is arranged directly below the center position of the capacitive load element 3 in the front-to-back direction in the antenna device 1. Figure 3 The reason why the average gain drops significantly near the longitudinal length L of the capacitive loading element 3 of λ and 2λ is that when the longitudinal length L of the capacitive loading element 3 is λ and 2λ, the longitudinal center of the TEL antenna 2 is directly below the maximum voltage point of the capacitive loading element 3. Figure 5 As described later, when the front-to-back length L of the capacitive load element 3 is λ / 2 or 3λ / 2, good gain can be obtained by positioning the front-to-back center of the TEL antenna 2 at the minimum voltage point of the capacitive load element 3 or within λ / 8 of the minimum voltage point.

[0075] Figure 4 This is a characteristic diagram based on simulation showing the relationship between the front-to-back distance x from the tip of the capacitive loading element 3 to the front-to-back center of the TEL antenna 2 and the average gain of the TEL antenna 2 at 1900 MHz when the front-to-back length L of the capacitive loading element 3 in the antenna device 1 is set to λ / 2. Figure 4 In the figure, λ / 4 on the horizontal axis corresponds to the minimum voltage point of the capacitive load element 3. Figure 4By setting the front-to-back distance x from the front end of the capacitive load element 3 to the front-to-back center of the TEL antenna 2 to λ / 8≤x≤3λ / 8, a good antenna gain of 3 dBi or more can be achieved.

[0076] Figure 5 This is a characteristic diagram based on simulation showing the relationship between the front-to-back distance x from the tip of the capacitive loading element 3 to the front-to-back center of the TEL antenna 2 and the average gain of the TEL antenna 2 at 1900 MHz when the front-to-back length L of the capacitive loading element 3 in the antenna device 1 is set to λ. Figure 5 In the figure, λ / 4 and 3λ / 4 on the horizontal axis correspond to the minimum voltage points of the capacitive load element 3. Figure 5 By setting the front-to-back distance x from the front end of the capacitive load element 3 to the front-to-back center of the TEL antenna 2 to λ / 8≤x≤3λ / 8 or 5λ / 8≤x≤7λ / 8, a good antenna gain of approximately 3dBi or more can be achieved.

[0077] According to this embodiment, in the antenna device 1, the TEL antenna 2 is located below the capacitive loading element 3. This allows for greater miniaturization compared to a case where the TEL antenna 2 avoids the capacitive loading element 3 and moves away from it in the front-to-back direction (Comparative Example 1, described below). Furthermore, since the front-to-back center of the TEL antenna 2 is positioned away from the vicinity of the maximum voltage point of the capacitive loading element 3, a decrease in antenna gain can be suppressed. In particular, when the front-to-back center of the TEL antenna 2 is located near the minimum voltage point of the capacitive loading element 3 (for example, within a range of λ / 8 from the minimum voltage point), an antenna gain comparable to that of the TEL antenna 2 alone is achieved.

[0078] (Implementation Method 2)

[0079] Reference Figures 6 to 17 、 Figure 19 、 Figure 20 , describing embodiment 2 of the present invention. Figure 6 It is a schematic diagram of an antenna device 1A according to a second embodiment of the present invention. Figure 6 The structure of the antenna device 1A shown is similar to Figure 1 In contrast, the capacitance load element 3 includes the second plate-shaped portion 3b and the first plate-shaped portion 3a (equivalent to Figure 1 The capacitance load element 3 as a whole) and the second plate-shaped portion 3b are connected to each other via the filter 16, but are identical in other points. Figure 6 The relative positional relationship between the TEL antenna 2 and the first plate-shaped portion 3a is shown in FIG. Figure 1The relative positional relationship between the TEL antenna 2 and the capacitive load element 3 is the same as in the embodiment. The second plate-shaped portion 3b is located behind the first plate-shaped portion 3a. Filter 16 is a band elimination filter (BEF). In this embodiment, it blocks frequencies near the transmit / receive band of the TEL antenna 2. In this embodiment, the inclusion of the second plate-shaped portion 3b increases the overall size of the capacitive load element 3, improving performance in the AM / FM band.

[0080] Figure 7 It is an exploded perspective view of the antenna device 1A. Figure 13 It is a right side view of the antenna device 1A. Figure 14 : is a right side cross-sectional view of the antenna device 1A. Figure 7 and Figure 14 middle, Figure 13 Illustration of the outer housing 20 is omitted. The first plate portion 3a and the second plate portion 3b of the capacitance load element 3 are attached to the upper portion of the inner housing 6 by screws 101 and 102, respectively (threaded fastening).

[0081] The capacitive load element 3 is made of SUS (stainless steel) for rust prevention, but a conductive body sandwiched between insulating films can also be attached to the inner housing 6 as the capacitive load element 3. The capacitive load element 3 can also be a structure formed by printing a conductive pattern on a flexible substrate. In addition, metal powder can be evaporated on the inner housing 6 to form the capacitive load element 3. The capacitive load element 3 is formed into a shape with a cross-section convex upward, and is arranged approximately parallel to the top of the base 10 described later, with the longitudinal direction as the front-to-back direction.

[0082] In order to prevent the capacitive load element 3 from expanding in the left-right direction from the inner housing 6, the lower portion of the capacitive load element 3 has a plurality of substantially vertical tongue portions 3c (four on each side). Figure 8 As shown, each tongue portion 3c is inserted into a groove portion 6a provided in the inner case 6, thereby retaining the capacitive loading element 3 on the inner case 6. By providing the substantially vertical tongue portion 3c at the bottom of the capacitive loading element 3, the surface area facing the ground can be reduced compared to a configuration in which tongue portions are provided in the left-right direction. This reduces parasitic capacitance and prevents a decrease in the gain of the AM / FM antenna.

[0083] like Figure 9As shown, the capacitive loading element 3 can be configured to include a tongue portion 3c at the rear end of the upper portion, which is clamped into a groove portion 6a of the inner housing 6 provided at a corresponding position. Furthermore, although not shown, a configuration can also be configured to include a tongue portion 3c at the front end of the upper portion of the capacitive loading element 3, which is also clamped into the groove portion 6a of the inner housing 6. When the tongue portion 3c is provided at the front or rear end of the upper portion of the capacitive loading element 3, the upper portion of the capacitive loading element 3 is extended in the front-to-back direction by the length of the tongue portion 3c. This further enhances the capacitive loading effect without increasing the size of the inner housing 6, thereby improving the gain of the AM / FM antenna.

[0084] It should be noted that the capacitive load element 3 may also be mounted on the inner housing 6 by welding, bonding, or the like. Furthermore, the capacitive load element 3 may have one of the first plate-shaped portion 3a and the second plate-shaped portion 3b screwed to the upper portion of the inner housing 6, while the other may be integrally formed and retained in the inner housing 6 without screw fastening. Alternatively, both the first plate-shaped portion 3a and the second plate-shaped portion 3b may be integrally formed and retained in the inner housing 6 without screw fastening.

[0085] The inner shell 6 is made of radio wave transparent synthetic resin (a molded product made of resin such as ABS resin). The inner shell 6 is mounted on the base 10 by six screws 103. Figure 13 As shown, the inner case 6 is covered by the outer case 20. That is, the antenna device 1A includes the TEL antenna 2 and the capacitive load element 3 in the common outer case 20.

[0086] The TEL antenna 2 is a conductor pattern provided on the TEL antenna substrate 4 and is capable of transmitting and receiving AMPS and PCS bands. The TEL antenna substrate 4 is mounted upright on the amplifier substrate 9, approximately perpendicular to the substrate 10 and approximately parallel to the longitudinal direction of the capacitive load element 3. In other words, the TEL antenna 2 is approximately perpendicular to the substrate 10. The TEL antenna substrate 4 is provided with a spiral element 5, a filter 16, and terminals 17 and 18. A pair of connecting plates 13 are attached to the inner housing 6 using screws 104, electrically connecting the first plate-shaped portion 3a and the second plate-shaped portion 3b of the capacitive load element 3 to the pair of terminals 17. The pair of terminals 18 are held and electrically connected by a pair of conductive leaf springs (terminals) 9a provided on the amplifier substrate 9. The lower end of the TEL antenna 2 is held and electrically connected by a conductive leaf spring 9b on the amplifier substrate 9. The bracket 7, while holding the TEL antenna substrate 4, is attached to the inner housing 6 using two screws 105. The TEL antenna 2 is located approximately in the left-right center of the antenna device 1A, which can suppress interference with the capacitive load element 3 and improve AM / FM performance. In addition, the upper portion of the outer shell 20 can be made thinner to improve the design. Figure 7The spiral element 5 is offset (deviation) to the right, and the winding axis (central axis) of the spiral element 5 is substantially parallel to the up-down direction and substantially perpendicular to the left-right direction.

[0087] The amplifier substrate 9 is mounted on the base 10 by nine screws 106. Conductor leaf springs 9a and 9b, a GPS (Global Positioning System) antenna 21, an XM (satellite radio) antenna 22, and an AM / FM / XM / GPS amplifier and a TEL matching circuit (not shown) are provided on the amplifier substrate 9. A waterproof gasket (water-tightening fastener) 8 is an annular elastic member made of elastomer or rubber, and is provided on the base 10. The waterproof gasket 8 is pressed against the base 10 over the entire circumference by the lower end of the inner housing 6 fixed by screw fastening, etc., thereby watertightly sealing the space between the base 10 and the inner housing 6. The sealing member 15 is an annular elastic member made of elastomer, polyurethane, or rubber, and is clamped between the lower surface of the base 10 and the vehicle body (e.g., the roof of a vehicle) where the antenna device 1A is installed, thereby watertightly sealing the space between the two. Bolts (vehicle body mounting screws) 11 are screwed to the base 10 via washers 12 and brackets 14 to fix the antenna device 1A to the roof of the vehicle or the like.

[0088] The connector 9c provided on the lower surface of the amplifier substrate 9 is connected to the connector hole 10b ( Figure 7 By exposing the connector 9c from the connector hole 10b of the base body 10, it is not necessary to prepare various cables according to the shape of the vehicle, which can achieve cost reduction.

[0089] The base 10 has a structure with a step downward near the catch portion (gasket 12) of the base 10 for obtaining a press-fit connection with the vehicle (near the left-right center of the base 10 in this embodiment). Figure 14As shown, the lower surface of the base 10 has a convex portion 10a on the inner side of the sealing member 15 that protrudes downward compared to the outer side. This structure reduces the gap between the base 10 and the vehicle near the catch portion of the base 10, thereby increasing capacitive coupling. This suppresses the occurrence of unnecessary resonance caused by the size of the base 10 (reducing the amplitude of the unnecessary resonant frequency), thereby minimizing the gain drop of the TEL antenna 2. Furthermore, in the high-frequency band, the gap between the base 10 and the vehicle is small near the catch portion of the base 10. Therefore, when achieving a press-fit connection between the catch portion and the vehicle, the length of the catch portion's path can be ignored, further minimizing the gain drop of the TEL antenna 2. Furthermore, the convex portion 10a on the lower surface of the base 10 increases the gap between the base 10 and the vehicle outside the catch portion, reducing capacitive coupling between the base 10 and the vehicle. This allows for the adaptation of vehicle roofs with various curvatures. The reasons for this are explained below. Outside the vicinity of the capture portion, the curvature of the vehicle's roof changes away from the fastening base point, so the change in the gap between the vehicle roof and the base 10 increases, and the change in capacitive coupling also increases. If the gap between the base 10 and the vehicle is reduced in the same manner as in the vicinity of the capture portion, the capacitive coupling increases, and the change in capacitive coupling is also large, so the change in the frequency of occurrence of unnecessary resonance increases, sometimes causing adverse effects on the required frequency band. Due to the structure of the convex portion 10a, the gap between the base 10 and the vehicle is large outside the vicinity of the capture portion, so the capacitive coupling is reduced, and even if the change in capacitive coupling is large, the change in the frequency of occurrence of unnecessary resonance is not too large. Therefore, it is possible to cope with vehicle roofs of various curvatures. It should be noted that the convex portion 10a can extend to the outside of the sealing member 15. It is preferred to have a structure that can avoid unnecessary resonance from occurring in the band of 700MHz to 960MHz.

[0090] The following describes the reason why the XM antenna 22, GPS antenna 21, TEL antenna 2, and helical element 5 (part of the AM / FM antenna) are arranged in this order from front to back in antenna device 1A. Regarding the bandwidths of the antennas, the XM antenna 22 operates in the 2.3 GHz band, the GPS antenna 21 operates in the 1.5 GHz band, the TEL antenna 2 operates in the 700 MHz to 900 MHz band, the 1.7 GHz to 2.1 GHz band, and the 2.5 GHz to 2.6 GHz band, and the helical element 5 operates in the 522 kHz to 1710 kHz band (for AM) and the 76 MHz to 108 MHz band (for FM).

[0091] 1. The bandwidths of the GPS antenna 21 and XM antenna 22 are close to the bandwidth of the TEL antenna 2. Therefore, to ensure mutual isolation, the distance between the GPS antenna 21 and XM antenna 22 and the TEL antenna 2 must be increased. Therefore, by placing a connector 9c between the placement space for the GPS antenna 21 and XM antenna 22 and the placement space for the TEL antenna 2, mutual isolation can be ensured and the placement space can be reduced. The XM antenna 22 is positioned forward of the GPS antenna 21 to minimize interference between nearby antennas by placing them forward in descending order of frequency. This is because, for example, if an XM antenna 22, operating at a higher frequency than the GPS antenna 21, is positioned near the TEL antenna 2, the wavelength of the XM antenna 22 is smaller than that of the GPS antenna 21. Therefore, the size of the TEL antenna 2 cannot be ignored, resulting in greater interference than if the GPS antenna 21 is positioned near the TEL antenna 2.

[0092] 2. To secure the antenna device 1A so as to avoid increasing the gap between the antenna device 1A and the vehicle roof, a bolt 11 is screwed into the base 10 near the center of the antenna device 1A in the front-to-back and left-to-right directions, so that the claw tip of the washer (catch) 12 achieves a voltage-tight connection with the vehicle. The TEL antenna 2 is connected to the vehicle equipment via a connector 9c, which is directly exposed from a hole in the base 10 near the bolt 11, and a cable (not shown). As the distance between the TEL antenna 2 and the bolt 11 increases, the path between the TEL antenna 2 and the bolt 11 increases in electrical length, causing the current generated in the base 10 to cancel out the current generated in the vehicle roof (current that should be excited in the TEL antenna 2 flows toward the vehicle), which may reduce the gain of the TEL antenna 2. Therefore, the power supply position for the TEL antenna 2 is preferably located near the center of the antenna device 1A in the front-to-back and left-to-right directions.

[0093] 3. Considering the aerodynamic forces of the vehicle where the antenna device 1A is mounted, the antenna device 1A preferably rises vertically from the front toward the rear. Therefore, the XM antenna 22 and GPS antenna 21, which are relatively low in the vertical direction, are preferably located in the front. The XM antenna 22 and GPS antenna 21 are relatively low in the vertical direction because they require high frequencies and short wavelengths, allowing for miniaturization.

[0094] For the above three reasons, the XM antenna 22, the GPS antenna 21, the TEL antenna 2, and the helical element 5 are arranged in this order from the front.

[0095] Figure 11 (A)~ Figure 11(C) is a schematic top view showing the relative positional relationship between the TEL antenna 2 and the helical element 5 in each case where the winding shape of the helical element 5 is a circle, an ellipse long in the left-right direction, and an ellipse long in the front-back direction. The helical element 5 is wound in a spiral shape, and when viewed from the top and bottom direction (winding axis direction), the helical element 5 is wound in a spiral shape. Figure 7 In the example, it is roughly circular ( Figure 11 (A)) but can also be rotated as Figure 11 (B) and Figure 11 (C) shows an elliptical shape and rotates. The elliptical shape has the following two effects.

[0096] 1. When the distance between the TEL antenna 2 and the helical element 5 is short, parasitic capacitance may occur between them. To prevent this phenomenon, it is desirable to increase the distance between the TEL antenna 2 and the helical element 5. However, it is difficult to increase the distance within the narrow inner housing 6. Therefore, Figure 11 As shown in (B), by making the helical element 5 rotate in an elliptical shape that is long in the left-right direction, the distance between the TEL antenna 2 and the helical element 5 is increased, thereby improving the insulation and suppressing the occurrence of parasitic capacitance between the two. Figure 11 As shown in (C), when the helical element 5 is rotated in an elliptical shape that is long in the front-back direction, the surface of the helical element 5 facing the TEL antenna 2 is reduced. Therefore, even if the distance between the TEL antenna 2 and the helical element 5 is greater than Figure 11 The TEL antenna 2 shown in (A) has the same separation distance from the helical element 5 , and can also improve the insulation between the two, thereby suppressing the occurrence of parasitic capacitance between the two.

[0097] 2. By rotating the spiral element 5 in an elliptical shape, when the minor diameter of the ellipse is equal to the diameter of a perfect circle, the projected area of ​​the spiral element 5 when viewed from above is larger than that of a perfect circle. This allows for greater electrical length than a perfect circle, thereby increasing the degree of freedom in the front-to-back arrangement within the inner housing 6. Furthermore, the increased projected area of ​​the spiral element 5 when viewed from above can suppress high-frequency losses.

[0098] The above is the effect when the spiral element 5 is elliptical and rotates. It should be noted that the spiral element 5 can be in a polygonal shape such as a rectangle.

[0099] Helical element 5 Figure 7In the example, it is offset (deviated) to the right from the left-right center of the antenna device 1A, but it can also be located at the left-right center. The winding axis (center axis) of the helical element 5 can be tilted in the front-to-back direction (the winding axis of the helical element 5 is not approximately parallel to the up-down direction). As a result, the distance between the helical element 5 and the TEL antenna 2 can be extended, and the electrical length of the helical element 5 can also be extended. Moreover, the winding axis of the helical element 5 can also be tilted in the left-to-right direction (the winding axis of the helical element 5 is not approximately perpendicular to the left-to-right direction). The effect produced by this is the same as when it is tilted in the front-to-back direction. The helical element 5 is constructed so as to avoid overlapping with the capacitive load element 3 and the components on the amplifier substrate 9 in the up-down direction. As a result, the occurrence of parasitic capacitance between the helical element 5 and the capacitive load element 3 or between the helical element 5 and the components on the amplifier substrate 9 can be suppressed.

[0100] Figure 10 (A)~ Figure 10 (F) is an exploded perspective view of the helical element 5, the bracket 7, and the TEL antenna substrate 4. The helical element 5 is held by the bracket 7 from the outside. Specifically, the bracket 7 has a helical element holding portion 7a that accommodates the helical element 5, and the helical element holding portion 7a holds the helical element 5 from the outside. The lead portions 5a of the helical element 5 are inserted into the helical element connection holes 4a of the TEL antenna substrate 4. Since more high-frequency current flows on the inner circumference of the helical element 5 than on the outer circumference, high-frequency loss is less likely to occur when the helical element 5 is held by the bracket 7 from the outside than when it is held by the bracket 7 from the inside. Furthermore, by holding the helical element 5 by the helical element holding portion 7a from the outside, the maximum outer diameter of the helical element 5 does not exceed the inner diameter of the bracket 7, thereby suppressing fluctuations in the electrical length of the helical element 5. Furthermore, a groove (not shown) can be excavated on the inner surface of the helical element holding portion 7a of the bracket 7, and the helical element 5 can be arranged so as to be accommodated in the groove. In this case, the effect of suppressing the variation in the electrical length of the spiral element 5 and maintaining the spacing between the conductors of the spiral element 5 is achieved. It should be noted that the spiral element 5 can also be held by the bracket 7 from the inside. That is, the spiral element 5 can be in a shape that is wound around the bracket 7. In addition, a groove can be dug in the bracket 7 and the spiral element 5 can be accommodated in the groove. The effect produced thereby is the same as when it is accommodated in the groove on the inner surface of the spiral element holding portion 7a. The bracket 7 is mounted on the TEL antenna substrate 4. The bracket 7 holds the spiral element 5 and is mounted on the TEL antenna substrate 4, so the positional relationship between the TEL antenna 2 and the spiral element 5 is determined, and performance changes caused by mutual positional deviation can be avoided. It should be noted that the bracket 7 can also be omitted if there is no adverse effect on use due to vibration, etc.

[0101] The feed point (terminal 18) of helical element 5 is located close to helical element 5. This positions helical element 5 behind antenna device 1A, allowing an amplifier (not shown) to be installed on amplifier substrate 9. Furthermore, conductor loss and parasitic capacitance of the feed line from the feed point to helical element 5 can be reduced. Furthermore, by limiting the length of the feed line to approximately 32 mm or less, which is one-quarter the wavelength of XM antenna 22, any reduction in the gain of XM antenna 22 due to the length of the feed line can be suppressed. Furthermore, since the connection point (terminal 17) between capacitive load element 3 and helical element 5 is located close to helical element 5, the same effects as described above can be achieved.

[0102] like Figure 13 As shown, the front-to-back dimension of the first plate-shaped portion 3a of the capacitive loading element 3 is approximately 50 mm, which is an electrical length of approximately half the wavelength of the PCS band and an electrical length that does not resonate in the PCS band. Furthermore, the front-to-back dimension of the second plate-shaped portion 3b of the capacitive loading element 3 is approximately 23 mm, an electrical length that does not resonate in the PCS band. Furthermore, the combined total length of the first and second plate-shaped portions 3a, 3b of the capacitive loading element 3 is approximately 80 mm, an electrical length that does not resonate in the AMPS band.

[0103] like Figure 14 and Figure 15 As shown, the passive element 25 covers the XM antenna 22 from above, leaving a space therebetween. The passive element 25 is attached to the lower surface of the inner case 6 by, for example, welding. Covering the XM antenna 22 with the passive element 25 increases the gain in the vertex direction of the XM antenna 22. The GPS antenna 21 may also be covered with the passive element 25.

[0104] Filter 16 electrically separates the first and second planar portions 3a, 3b of the capacitive load element 3 at high frequencies (above the frequency band of the TEL antenna 2) and electrically connects them at low frequencies (below the AM / FM band). Filter 16 is located between the first planar portion 3a, which is closer to the TEL antenna 2, and the helical element 5. It is not located between the second planar portion 3b, which is farther away from the TEL antenna 2, and the helical element 5. Because the TEL antenna 2 is closer to the first planar portion 3a, high-frequency currents may flow from the first planar portion 3a through the helical element 5 and into the AM / FM amplifier during transmission. Filter 16 blocks this current. Since the TEL antenna 2 is farther away from the second planar portion 3b, this current is less likely to flow. Therefore, filter 16 is not provided to reduce costs. If the attenuation provided by filter 16 is insufficient, an additional filter can be added between the capacitive load element 3 and the helical element 5.

[0105] The TEL antenna substrate 4 and the amplifier substrate 9 are electrically connected at the power supply point by the elasticity of the conductor leaf springs 9a and 9b as M-shaped springs ( Figure 12 ). When the number of power supply points increases, the shape of the conductor leaf springs 9a and 9b (M-shaped spring) often causes unstable fixation and unstable contact resistance. In addition, the contact resistance of the conductor leaf springs 9a and 9b may vary due to cross assembly. Therefore, it is possible to Figure 12 As shown, protrusions 9d facing each other are provided on the inner sides of the conductor leaf springs 9a and 9b, which serve as M-shaped springs. These protrusions 9d sandwich the TEL antenna substrate 4, thereby stabilizing the contact resistance of the conductor leaf springs 9a and 9b. It should be noted that protrusions can be provided on the TEL antenna substrate 4 side instead of the conductor leaf springs 9a and 9b. Furthermore, protrusions can be provided on both. This also applies to the connection point between the capacitive load element 3 and the TEL antenna substrate 4 (the portion where the connection plate 13 and the TEL antenna substrate 4 are connected).

[0106] Figure 16It is the connection circuit diagram (Part 1) of the antenna device 1A. The first plate-like portion 3a and the second plate-like portion 3b of the capacitive load element 3, and the helical element 5 constitute a vertex capacitive load type inverted F antenna. The AM / FM broadcast waves received by this inverted F antenna are transmitted to the amplifier substrate 9. One end of the helical element L1 among the helical elements 5 (L1 to L3) constituting the inverted F antenna is connected to the second plate-like portion 3b and is also connected to one end of the filter 16. The other end of the helical element L1 is connected to one ends of the helical elements L2 and L3. The other end of the helical element L2 is connected to the power supply point. The other end of the helical element L3 is connected to one end of the filter 19. The other end of the filter 19 is connected to the ground. The impedance and resonance frequency of the antenna can be adjusted by varying the inductance relationship of the helical elements 5 (L1 to L3) constituting the inverted F antenna. Specifically, the impedance of the antenna can be adjusted by the inductance of the helical element 5 (L3) connected to the ground. When the inductance is increased, the impedance decreases, and when the inductance is decreased, the impedance increases. Moreover, the resonance frequency can be adjusted by adjusting the inductances of the other two helical elements 5 (L1, L2). Here, the inductances of the respective helical elements 5 have a relationship of L1 < L2 < L3. If an example of specific values is given, it is L1: 127 nH, L2: 425 nH, L3: 929 nH. The antenna mode for AM / FM can be an inverted L or a front-end short Braun, but by using an inverted F antenna, the impedance in the FM band can be increased, the impedance variation when adding the TEL antenna 2 can be reduced, and the influence of the TEL antenna 2 can be alleviated. The filter 19 is a band-pass filter (BPF: Band Pass Filter) in the FM band. Since the AM band is no longer received when grounded by using an inverted F antenna, the filter 19 that only allows the FM band to pass is loaded to reduce the degradation of the AM band.

[0107] Figure 17 It is the connection circuit diagram (Part 2) of the antenna device 1A. In the Figure 17 circuit, the different point from Figure 16 is that a filter 26 as a second filter is provided between the helical element 5 and the amplifier substrate 9. The filter 26 is provided on the TEL antenna substrate 4 side instead of on the amplifier substrate 9 side. As a result, the impedance of the TEL band on the helical element 5 side is increased compared to the power supply point of the helical element 5, the high-order harmonics of the FM resonance generated in the helical element 5 can be suppressed, and the gain drop of the TEL antenna 2 can be suppressed. The filter 26 can be a parallel resonance circuit of a chip inductor and a chip capacitor, or can be a chip inductor whose self-resonance frequency is close to the required frequency band of the TEL antenna 2. Instead of chip components, the helical element 5 itself can also have this function. It should be noted that a structure that can avoid the occurrence of high-order harmonics in the band range of 700 MHz to 960 MHz is preferred.

[0108] Figure 19 This is a characteristic diagram based on simulations showing the relationship between frequency and average gain (dashed line and dashed line) of the TEL antenna 2 of the antenna device 1A of the second embodiment and the antenna device 1B of the third embodiment described later, together with the relationship between frequency and average gain (solid line) of the TEL antenna 2 alone (without the capacitive load element 3). Figure 19 The antenna gain of the TEL antenna 2 of the antenna device 1A of this embodiment is also the same as the antenna gain of the TEL antenna 2 of the antenna device 1 of the first embodiment ( Figure 2 ) Similarly, the same good characteristics as those of the TEL antenna 2 alone are achieved.

[0109] Figure 20 This is a characteristic diagram based on actual measurement showing the relationship between the frequency and the average gain of the TEL antenna 2 when the capacitance load element 3 is divided into the first plate-shaped portion 3a and the second plate-shaped portion 3b and when it is not divided into the first plate-shaped portion 3a and the second plate-shaped portion 3b. Figure 20 As can be seen, by dividing the capacitive loading element 3 into the first plate-shaped portion 3a and the second plate-shaped portion 3b along the front-to-back direction, interference between the capacitive loading element 3 and the TEL antenna 2 can be suppressed, thereby ensuring the average gain of the TEL antenna 2. Further dividing the capacitive loading element 3 along the front-to-back direction can further suppress interference, but this division reduces manufacturing efficiency and complicates the circuit, leading to increased costs. Therefore, it is preferable to divide the capacitive loading element 3 into two parts along the front-to-back direction, as in antenna device 1A.

[0110] (Implementation 3)

[0111] Figure 18 It is a schematic diagram of an antenna device 1B according to a third embodiment of the present invention. Figure 18 The antenna device 1B shown has a meander line 23 instead of Figure 6 The filter 16 of the antenna device 1A shown in FIG. The bending line 23 connects the first plate-shaped portion 3a and the second plate-shaped portion 3b of the capacitive load element 3. The other points of this embodiment are the same as those of the second embodiment. Figure 19 As shown, the antenna gain of the TEL antenna 2 of the antenna device 1B of this embodiment is also similar to the antenna gain of the TEL antenna 2 of the antenna device 1A of the second embodiment, and has good characteristics substantially the same as those of the TEL antenna 2 alone.

[0112] (Comparative Example 1)

[0113] Figure 21 is a schematic diagram of an antenna device according to Comparative Example 1. Figure 1Compared with the structure of the first embodiment shown, the structure is different in that the TEL antenna 2 is separated from the capacitive load element 3 in the front-to-back direction. Specifically, the center position of the TEL antenna 2 in the front-to-back direction is separated from the front end of the capacitive load element 3 by 30 mm. Other points are the same.

[0114] Figure 23 This is a characteristic diagram based on simulations showing the relationship between frequency and average gain (dashed line and dashed line) of the TEL antenna 2 of the antenna apparatus of Comparative Example 1 and Comparative Example 2 described later, and the relationship between frequency and average gain (solid line) of the TEL antenna 2 alone (without the capacitive load element 3). Figure 23 The antenna gain of the TEL antenna 2 of the antenna device of Comparative Example 1 is substantially the same as that of the TEL antenna 2 alone. However, since the TEL antenna 2 is spaced forward from the capacitive load element 3, the antenna device becomes larger.

[0115] (Comparative Example 2)

[0116] Figure 22 is a schematic diagram of an antenna device according to Comparative Example 2. Figure 1 Compared to the structure of the embodiment 1 shown in FIG. 1 , the center position of the TEL antenna 2 in the front-back direction is aligned with the front end of the capacitive loading element 3, but the other points are aligned. Comparative Example 2 is an example in which the distance between the TEL antenna 2 and the front end of the capacitive loading element 3 in the center position in the front-back direction is set to 0 mm in Comparative Example 1. In the case of Comparative Example 2, the TEL antenna 2 and the capacitive loading element 3 are close in the front-back direction, so the antenna device can be made small. However, due to the influence of the capacitive loading element 3, as shown in FIG. Figure 23 As shown, the antenna gain of the TEL antenna 2 is significantly deteriorated compared to the case of the TEL antenna 2 alone.

[0117] Figure 24 This is a characteristic diagram based on simulation showing the relationship between the distance from the capacitive load element 3 and the average gain in the TEL antenna 2 of the comparative example. 30 mm on the horizontal axis corresponds to the comparative example 1, and 0 mm corresponds to the comparative example 2. Figure 24 In the technical concept of placing the TEL antenna 2 away from the capacitive load element 3 to avoid the influence of the capacitive load element 3, the TEL antenna 2 needs to be separated from the capacitive load element 3 in order to improve the antenna gain of the TEL antenna 2. In contrast, in the above-mentioned first to third embodiments, the TEL antenna 2 can be placed below the capacitive load element 3 to improve the antenna gain of the TEL antenna 2, thereby suppressing the reduction in antenna gain and achieving miniaturization.

[0118] (Implementation 4)

[0119] Figure 25 It is a perspective view of an antenna device 1C according to a fourth embodiment of the present invention. Figure 26 is Figure 25 The perspective view of the inner housing 6 is omitted. The antenna device 1C of this embodiment differs from the antenna device 1A of Embodiment 2 in that the first plate-shaped portion 3a of the capacitance load element 3 is provided with a cutout portion 3d. The antenna device 1C is identical in other respects. The cutout portion 3d gives the first plate-shaped portion 3a a square shape with one side missing when viewed from above ( The first plate-shaped portion 3a is formed in a truncated or U-shaped configuration and is divided in the left-right direction except for the rear end. This configuration provides a pair of sides that face each other across the notch 3d. High-frequency currents tend to flow in opposite directions along these sides, facilitating cancellation of harmonic components with frequencies higher than the FM band excited in the capacitive load element 3. This allows antennas with different resonant frequencies (capacitive load element 3 and TEL antenna 2) to be spaced closer together.

[0120] Figure 27 This is a characteristic diagram based on simulation showing the relationship between the frequency and average gain of the FM band of the AM / FM antenna in each case where the capacitance load element 3 has the notch portion 3d and when the capacitance load element 3 does not have the notch portion 3d. Figure 27 By forming the first plate-shaped portion 3a of the capacitance load element 3 into a square shape with one side missing as described above ( The average gain of the TEL antenna 2 can be increased by increasing the distance between the capacitance load element 3 and the TEL antenna 2. This is because the parasitic capacitance can be reduced. Furthermore, the first plate-shaped portion 3a is formed into a square with one side missing ( The first plate-shaped portion 3a is formed into a U-shaped portion, thereby improving the efficiency of mounting the first plate-shaped portion 3a on the inner housing 6 compared to the case where the first plate-shaped portion 3a is composed of two plate-shaped portions separated left and right. In addition, the number of screws can be reduced, which can lead to cost reduction.

[0121] Figure 28This is a front cross-sectional view of an antenna device 1D according to a fifth embodiment of the present invention. Antenna device 1D of this embodiment differs from antenna device 1A of the second embodiment in that the capacitive load element 3 is split left and right into a left plate-shaped portion 3e and a right plate-shaped portion 3f, and that the TEL antenna substrate 4 and the TEL antenna mounted on the TEL antenna substrate 4 protrude upward from between the left and right plate-shaped portions 3e and 3f. The antenna device 1D is identical in all other respects. Splitting the capacitive load element 3 left and right suppresses parasitic capacitance between the capacitive load element 3 and the TEL antenna 2, improving AM / FM performance. Furthermore, the TEL antenna substrate 4 and the TEL antenna mounted on the TEL antenna substrate 4 protrude upward from between the left and right plate-shaped portions 3e and 3f, improving TEL antenna performance. Figure 29 This is a characteristic diagram based on simulation showing the relationship between the frequency and average gain of the FM band of the AM / FM antenna when the capacitive load element 3 is divided into the left plate-shaped portion 3e and the right plate-shaped portion 3f and when it is not divided into the left and right. Figure 29 In the case of left and right division, the TEL antenna does not protrude upward from between the left plate upper portion 3e and the right plate upper portion 3f. Figure 29 By dividing the capacitive load element 3 into left and right parts, the average gain of the FM band of the AM / FM antenna can be improved.

[0122] While the present invention has been described above using embodiments as examples, those skilled in the art will appreciate that various modifications may be made to the various components and processes of the embodiments within the scope of the claimed invention. Modifications are described below.

[0123] The first antenna can replace the TEL antenna 2 and be a TV antenna, a keyless entry antenna, an inter-vehicle communication antenna, or a WiFi antenna. The second antenna can replace the AM / FM antenna and be a DAB (Digital Audio Broadcast) receiving antenna. Figure 18 In addition to the addition of the bending line 23 shown, the shape can be changed by adding a slit or forming a folded shape.

[0124] Description of Reference Numerals

[0125] 1. 1A to 1D antenna device, 2. TEL antenna (first antenna), 3. Capacitive load element (second antenna), 3a. First plate-shaped portion, 3b. Second plate-shaped portion, 3c. Tongue portion, 3d. Notch portion, 3e. Left plate-shaped portion, 3f. Right plate-shaped portion, 4. TEL antenna substrate, 4a. Helical element connection hole, 5. Helical element (AM / FM coil), 5a. Lead portion, 6. Inner housing, 6a. Groove portion, 7. Bracket, 7a. Helical element holding portion, 8. Waterproof pad (watertight seal), 9. Amplifier substrate, 9a. b conductor leaf spring (terminal), 9c connector, 9d protrusion, 10 base, 10a convex portion, 10b connector hole, 11 bolt (body mounting screw), 12 washer (catching portion), 13 connecting plate, 14 bracket, 15 sealing member, 16 filter (BEF), 17, 18 terminal portions, 19 filter (BPF), 20 outer shell (external casing), 21 GPS antenna, 22 XM antenna, 23 bending line, 25 passive component, 26 filter, 101 to 106 screws.

Claims

1. An antenna device comprising: fixed to a base of the vehicle; and an antenna element disposed on the substrate, The base body has a catch portion for achieving a press-fit connection with the vehicle and a step including a protrusion protruding from a lower surface of the base body toward the vehicle and provided near the catch portion. A sealing member is provided on the vehicle-side surface of the base body. The convex portion is located between the capturing portion and the sealing member, The lower surface of the base body inside the seal member is located closer to the vehicle than the lower surface of the base body outside the seal member.

2. The antenna device according to claim 1, wherein The antenna element is any one of a TEL antenna, a TV antenna, a keyless entry antenna, an inter-vehicle communication antenna, and a WiFi antenna.

3. The antenna device according to claim 1, wherein The base is fixed to the roof of the vehicle. The antenna device according to claim 1 , wherein: The antenna element is a TEL antenna, The TEL antenna is disposed near the step of the base.

5. The antenna device according to claim 2, wherein The antenna element is a TEL antenna, The TEL antenna is arranged near the capturing unit. The antenna device according to claim 1 , wherein: The convex portion is a structure for preventing unnecessary resonance from occurring in the frequency band of 700 MHz to 960 MHz.

7. The antenna device according to claim 1, wherein The antenna device includes an amplifier substrate mounted on the base body. The antenna element is electrically connected to the amplifier substrate by the elasticity of a conductor leaf spring.

8. The antenna device according to claim 7, wherein: The conductor leaf spring is in an M shape, and has protrusions facing each other on its inner side.

9. The antenna device according to claim 1, wherein The antenna device includes an amplifier substrate mounted on the base body. The connection position between the antenna element and the amplifier substrate is near the center in the width direction of the antenna device.

10. The antenna device according to claim 1, wherein The antenna device has a capacitive load element and a helical element constituting an FM antenna, The antenna element and the helical element are provided on the same antenna substrate. The antenna device according to claim 10 , wherein: The antenna device includes a bracket mounted on the antenna substrate and determining a positional relationship between the antenna element and the helical element in the antenna substrate.

12. The antenna device according to claim 10, wherein The antenna element is provided on the front side of the vehicle relative to the helical element.

13. The antenna device according to claim 10, wherein The antenna substrate is provided with a filter connected to the spiral element.

14. The antenna device according to claim 10, wherein The antenna element is a TEL antenna, The TEL antenna is provided at a position covered by the capacitance loading element when the antenna device is viewed from above.

15. The antenna device according to claim 10, wherein There are multiple spiral elements. The central axis of each of the helical elements is substantially parallel to the vertical direction of the antenna device.

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