Vehicle-mounted antenna device

Abstract

A vehicle-mounted antenna device (10A) includes an antenna base (100), an antenna housing (600) that forms a housing space together with the antenna base (100), a first monopole antenna (210) housed in the housing space, and a first un-fed element (300) provided above the first monopole antenna (210).

Description

Technical Field

[0001] This invention relates to a vehicle-mounted antenna device. Background Technology

[0002] In recent years, various vehicle-mounted antenna devices with cellular antennas have been developed. For example, in Patent Document 1, the cellular antenna has an insulating substrate that stands vertically relative to the antenna base, and a conductive portion provided on the insulating substrate. In Patent Document 2, the cellular antenna is formed by bending sheet metal.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2017 / 191811

[0006] Patent Document 2: US Patent No. 9093750 Summary of the Invention

[0007] In recent years, there has been an increasing demand for 5G mobile communication systems, especially Sub-6 and Frequency Range 1 (FR1) in frequency bands below 6 GHz. Based on this demand, high gain in a wide bandwidth including high-frequency bands such as 5 GHz to 6 GHz has been required in recent years. At the same time, antenna miniaturization is also required. On the other hand, as described in Patent Documents 1 and 2, for cellular antennas constructed only from conductive portions on an insulating substrate and bent sheet metal, it is difficult to ensure gain in the horizontal direction of the high-frequency band when miniaturizing the antenna; that is, it is difficult to ensure gain in the desired direction of the high-frequency band.

[0008] One objective of this invention is to ensure gain in desired directions in the high-frequency band while miniaturizing the antenna. Other objectives of this invention will become apparent from the description herein.

[0009] One aspect of the present invention is a vehicle-mounted antenna device, comprising:

[0010] Antenna base;

[0011] The antenna housing, together with the antenna base, forms a receiving space;

[0012] A monopole antenna housed within the housing space; and

[0013] An unfeeding element is positioned above the monopole antenna.

[0014] Invention Effects

[0015] According to the above-described method of the present invention, it is possible to ensure gain in the desired direction of the high-frequency band while miniaturizing the antenna. Attached Figure Description

[0016] Figure 1 This is a perspective view of the vehicle-mounted antenna device according to Embodiment 1.

[0017] Figure 2 This is a perspective view of a comparative example of a vehicle-mounted antenna device.

[0018] Figure 3 This is a diagram showing the radiation pattern of the gain of the first monopole antenna of the vehicle-mounted antenna device according to Embodiment 1 at a frequency of 6 GHz.

[0019] Figure 4 This is a diagram showing the radiation pattern of the gain of the first monopole antenna of the comparative example vehicle-mounted antenna device at a frequency of 6 GHz.

[0020] Figure 5 This is a diagram showing the radiation pattern of the gain of the second monopole antenna of the vehicle-mounted antenna device according to Embodiment 1 at a frequency of 6 GHz.

[0021] Figure 6 This is a diagram showing the radiation pattern of the gain of the second monopole antenna of the comparative example vehicle-mounted antenna device at a frequency of 6 GHz.

[0022] Figure 7 This is a graph showing the frequency characteristics of the first monopole antenna of the vehicle-mounted antenna device of Embodiment 1 in the horizontal direction and the first monopole antenna of the vehicle-mounted antenna device of the comparative example in the horizontal direction from 1.5 GHz to 6 GHz.

[0023] Figure 8 This is a graph showing the frequency characteristics of the second monopole antenna of the vehicle-mounted antenna device of Embodiment 1 in the horizontal direction and the second monopole antenna of the vehicle-mounted antenna device of the comparative example in the horizontal direction from 1.5 GHz to 6 GHz.

[0024] Figure 9 This is a perspective view of the vehicle-mounted antenna device according to Embodiment 2.

[0025] Figure 10 This is a graph showing the frequency response of the positive transfer coefficient S21 of the S-parameters of the first filter from 0 to 7 GHz.

[0026] Figure 11 This is a graph showing the frequency characteristics of the first monopole antenna of the vehicle-mounted antenna device of Embodiment 1 in the horizontal direction, the first monopole antenna of the vehicle-mounted antenna device of Embodiment 2 in the horizontal direction, and the first monopole antenna of the vehicle-mounted antenna device of the comparative example in the horizontal direction from 1.5 GHz to 6 GHz.

[0027] Figure 12 This is a graph showing the frequency characteristics of the second monopole antenna of the vehicle-mounted antenna device of Embodiment 1 in the horizontal direction, the second monopole antenna of the vehicle-mounted antenna device of Embodiment 2 in the horizontal direction, and the second monopole antenna of the vehicle-mounted antenna device of the comparative example in the horizontal direction from 1.5 GHz to 6 GHz.

[0028] Figure 13 This is a graph showing the average gain of the AM / FM broadcasting antenna of the vehicle-mounted antenna device of Embodiment 2 in the horizontal direction and the average gain of the AM / FM broadcasting antenna of the vehicle-mounted antenna device of the comparative example in the horizontal direction, from 80MHz to 120MHz.

[0029] Figure 14 This is a three-dimensional view of a modified vehicle-mounted antenna device. Detailed Implementation

[0030] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in all the drawings, the same reference numerals are used to denote the same constituent elements, and descriptions are omitted where appropriate.

[0031] In this specification, unless otherwise stated, ordinal numbers such as "first", "second", "third" are used only to distinguish components with the same name and do not imply any specific characteristics of the components (e.g., order or importance).

[0032] Figure 1 This is a perspective view of the vehicle-mounted antenna device 10A according to Embodiment 1.

[0033] Figure 1 In this diagram, the first direction X, the second direction Y, and the third direction Z represent the front-rear, left-right, and up-down directions of the vehicle-mounted antenna device 10A, respectively. The arrow direction indicating the first direction X (positive direction) represents the front direction of the vehicle-mounted antenna device 10A. The opposite direction of the arrow direction indicating the first direction X (negative direction) represents the rear direction of the vehicle-mounted antenna device 10A. The arrow direction indicating the second direction Y (positive direction) represents the left direction of the vehicle-mounted antenna device 10A. The opposite direction of the arrow direction indicating the second direction Y (negative direction) represents the right direction of the vehicle-mounted antenna device 10A. The arrow direction indicating the third direction Z (positive direction) represents the up direction of the vehicle-mounted antenna device 10A. The opposite direction of the arrow direction indicating the third direction Z (negative direction) represents the down direction of the vehicle-mounted antenna device 10A. Furthermore, in this embodiment, the horizontal plane direction means a direction parallel to the XY plane. (This will be discussed later.) Figure 2 , Figure 9 as well as Figure 14 The same applies to China.

[0034] The vehicle-mounted antenna device 10A includes an antenna base 100, a first antenna section 12, a second antenna section 14, a third antenna section 16, a fourth antenna section 18, and an antenna housing 600. The antenna housing 600 covers the antenna base 100 from above, forming a receiving space. The first antenna section 12, the second antenna section 14, the third antenna section 16, and the fourth antenna section 18 are received within the receiving space of the antenna housing 600. Furthermore, Figure 1 A mid-perspective drawing of the antenna housing 600.

[0035] The antenna base 100 is mounted on the roof of the vehicle. The roof is grounded.

[0036] The first antenna section 12 includes a first substrate 112, an antenna vibrator 200, and a first unfed element 300.

[0037] The antenna element 200 is disposed on a first substrate 112 disposed on the antenna base 100. The first substrate 112 is, for example, a PCB (Printed Circuit Board).

[0038] The antenna element 200 has multiple monopole antennas. Specifically, the antenna element 200 has a first monopole antenna 210 and a second monopole antenna 220. The first monopole antenna 210 includes a first component 212 and a second component 214. The second monopole antenna 220 includes a third component 222 and a fourth component 224. The first monopole antenna 210 and the second monopole antenna 220 are respectively connected to a first port 216 and a second port 226 provided on the first substrate 112. The first component 212 and the second component 214 connected to the first port 216, and the third component 222 and the fourth component 224 connected to the second port 226 have self-similar shapes, as described later, so the first monopole antenna 210 and the second monopole antenna 220 can operate in a wide bandwidth. Alternatively, the antenna element 200 may also have only a single monopole antenna. The first monopole antenna 210 and the second monopole antenna 220 are each antennas for long-distance communication, such as cellular antennas. Additionally, the first monopole antenna 210 and the second monopole antenna 220 are each, for example, at least one of the antennas for transmitting and receiving vertically polarized waves. However, the first monopole antenna 210 and the second monopole antenna 220 can also be antennas different from cellular antennas, such as V2X (Vehicle-to-everything) antennas or Wi-Fi (registered trademark) antennas.

[0039] In this embodiment, a monopole antenna refers to an antenna having a feed section opposite to a grounded part such as the roof of a vehicle, and a component on the opposite side of the grounded part, separated by the feed section, having a length approximately 1 / 4 of the wavelength of the lower limit of its operating frequency band as a radiating element. In this configuration, an imaginary radiating element is arranged on the opposite side of the component across the grounded part, thereby enabling the monopole antenna to operate. For example, a monopole antenna can operate in roughly the same way as a tapered slot antenna and a bow-knot antenna.

[0040] The first monopole antenna 210 is, for example, made of sheet metal. In this embodiment, the first monopole antenna 210 is formed by bending a generally U-shaped sheet metal. Alternatively, the first monopole antenna 210 may also be made of a conductive pattern provided on a substrate such as a PCB.

[0041] The lower ends of the first component 212 and the second component 214 are connected to the first port 216. The first port 216 is the feed section of the first monopole antenna 210. The first component 212 and the second component 214 have a symmetrical shape with respect to the first port 216. Specifically, the width of the first component 212 increases gradually or progressively from the lower end to the upper end. Therefore, the width of the first component 212 near the upper end is wider than the width of the first component 212 near the lower end. The same applies to the width of the second component 214. In this way, the first monopole antenna 210 has a self-similar shape. By making the first monopole antenna 210 a self-similar shape, the first monopole antenna 210 can operate in the broadband domain.

[0042] Furthermore, as self-similar antennas, antennas such as biconical antennas and bow-knot antennas maintain a similar shape even when their scale (size ratio) is changed. As a premise of self-similar antennas, their electrical characteristics will theoretically remain the same even if the antenna size or frequency changes. In practical designs, for purposes such as impedance adjustment, the shape of the isosceles triangular radiating element of biconical and bow-knot antennas can be modified to a shape like the first monopole antenna 210 in this embodiment. Even in such cases, the fixed electrical characteristics obtained based on the self-similar shape can be utilized.

[0043] The second monopole antenna 220 is positioned in front of the first monopole antenna 210. The second monopole antenna 220 is, for example, made of sheet metal. In this embodiment, the second monopole antenna 220 is made of sheet metal in a generally U-shape. Alternatively, the second monopole antenna 220 may also be made of a conductive pattern provided on a substrate such as a PCB.

[0044] The lower ends of the third component 222 and the fourth component 224 are connected to the second port 226. The second port 226 is the feed section of the second monopole antenna 220. The third component 222 and the fourth component 224 have a symmetrical shape with respect to the second port 226. Specifically, the width of the third component 222 increases gradually or progressively from its lower end to its upper end. Therefore, the width of the third component 222 near its upper end is wider than the width of the third component 222 near its lower end. The same applies to the width of the fourth component 224. In this way, the second monopole antenna 220 has a self-similar shape.

[0045] Furthermore, the first monopole antenna 210 may also have only one of the first component 212 or the second component 214. Similarly, the second monopole antenna 220 may also have only one of the third component 222 or the fourth component 224. That is, the vehicle-mounted antenna device 10A can be configured to have at least one component. For example, the vehicle-mounted antenna device 10A may have only one of the first component 212, the second component 214, the third component 222, or the fourth component 224.

[0046] The shape of the first monopole antenna 210 or the second monopole antenna 220 is not limited to the general U-shape of this embodiment. For example, each monopole antenna may also be rod-shaped, plate-shaped, planar, fan-shaped, or generally V-shaped. In addition, each monopole antenna may not be a self-similar shape.

[0047] The first unfed element 300 is disposed above the antenna element 200. Specifically, the negative projection of the first unfed element 300 in the third direction Z overlaps with at least a portion of the regions between the first monopole antenna 210, the second monopole antenna 220, and the region between the first monopole antenna 210 and the second monopole antenna 220. For example, the negative projection of the first unfed element 300 in the third direction Z may also overlap with one of the first monopole antenna 210 and the second monopole antenna 220, but not with the other of the first monopole antenna 210 and the second monopole antenna 220.

[0048] The first unfed element 300 functions as a secondary radiating element. A secondary radiating element is an element that enhances the directivity of the gain in a predetermined direction, such as the horizontal plane, of the electromagnetic wave generated and radiated by the antenna element 200, which is a primary radiating element. Furthermore, the first unfed element 300 is electrically connected to the antenna element 200 at a predetermined frequency of 5.5 GHz to 6.0 GHz. Specifically, the first unfed element 300 functions as an element that enhances the directivity of the gain in the horizontal plane direction of at least one of the first monopole antenna 210 and the second monopole antenna 220 at a predetermined frequency. Furthermore, at the predetermined frequency of 5.5 GHz to 6.0 GHz, the first unfed element 300 functions approximately as an array antenna element relative to the antenna element 200. Thus, the vehicle-mounted antenna device 10A appears to have two wave sources: a wave source composed of the antenna element 200 and a wave source composed of the first unfed element 300. By including the first unfed element 300, compared to the case without the first unfed element 300, it is possible to minimize the size of the antenna element 200 while ensuring gain in the horizontal direction of the high-frequency band. For example, using... Figures 3 to 8 As will be described later, by providing the first unfed element 300, compared to the case where the first unfed element 300 is not provided, the gain at frequencies of, for example, 5.5 GHz to 6.0 GHz can be increased. Thus, the radiating element, including the antenna vibrator 200 and the first unfed element 300, becomes directional in the horizontal direction.

[0049] By appropriately adjusting the distance between the antenna element 200 and the first unfed element 300, the gain of the antenna element 200 in the horizontal direction can be enhanced. For example, the distance between the end of the antenna element 200 side of the first unfed element 300 and the end of the antenna element 200 on the first unfed element 300 side can be set to approximately λ / 2, such as λ / 2 to λ / 4 or more and λ / 2+λ / 4 or less. Here, λ is the wavelength of the frequency at which the gain of the antenna element 200 is enhanced by the first unfed element 300. When the distance is approximately λ / 2, compared to a distance significantly different from approximately λ / 2, the gain of the antenna element 200 in the horizontal direction can be further enhanced by the first unfed element 300.

[0050] The first unpowered element 300 is composed of multiple element portions that are spaced apart from each other. Specifically, the first unpowered element 300 is composed of a first element portion 310 and a second element portion 320. Furthermore, the first unpowered element 300 may also be composed of a single element portion or three or more element portions. When the first unpowered element 300 is composed of multiple element portions, compared to the case where the first unpowered element 300 is composed of a single element portion, by placing the multiple element portions in an appropriate configuration, the gain of the first unpowered element 300 can be significantly increased. The first element portion 310 and the second element portion 320 are symmetrically arranged with respect to the XZ plane. Specifically, the first element portion 310 is inclined in the horizontal direction such that the lower part of the first element portion 310 is located on the positive side of the second direction Y compared to the upper part of the first element portion 310. In contrast, the second element portion 320 is tilted from the horizontal plane such that its lower portion is located on the negative side of the second direction Y compared to its upper portion. In this case, compared to the case where the first element portion 310 and the second element portion 320 are arranged parallel to each other along the third direction Z, it is easier to house the first unfed element 300 within the housing space of the antenna housing 600. Furthermore, the first element portion 310 and the second element portion 320 can also be arranged parallel to each other along the third direction Z.

[0051] Alternatively, a first unfed element having at least one element portion can be provided above the first monopole antenna 210, and other first unfed elements having at least one element portion can be provided above the second monopole antenna 220. In this case, compared to the case where only one first unfed element is provided above the first monopole antenna 210 and the second monopole antenna 220, the shape, arrangement, and other conditions of each first unfed element on each monopole antenna can meet the conditions better for each monopole antenna, and the monopole antenna and each first unfed element can operate better.

[0052] Alternatively, when a single first unfed element is provided above a single monopole antenna, at least one of the front and rear ends of the monopole antenna assembly may be substantially aligned with at least one of the front and rear ends of the element portion of the first unfed element in the third direction Z. Since the front and rear ends of the monopole antenna assembly and the front and rear ends of the element portion of the first unfed element are prone to being at high potential, aligning the front and rear ends of the monopole antenna assembly and the front and rear ends of the element portion of the first unfed element facilitates electrical connection between the monopole antenna and the first unfed element.

[0053] The first element portion 310 is a quadrilateral in which the length in the longitudinal direction of the vehicle-mounted antenna device 10A is greater than the length of the side in the vertical direction of the vehicle-mounted antenna device 10A. The length of the portion of the first element portion 310 that forms a standing wave can be set to approximately λ / 2, for example, between λ / 2 and λ / 4 or more and between λ / 2 and λ / 4 or less. In particular, when transmitting and receiving vertically polarized waves using the antenna element 200 and the first unfed element 300, the length of the first element portion 310 in the vertical direction of the vehicle-mounted antenna device 10A can be set to approximately λ / 2, for example, between λ / 2 and λ / 4 or more and between λ / 2 and λ / 4 or less. Here, λ is the wavelength of the frequency at which the gain of the antenna element 200 is enhanced by the first unfed element 300. By setting this length of the first element portion 310 to approximately λ / 2, resonance is easily generated at the first element portion 310, and the gain is easily further enhanced through the first element portion 310. Furthermore, within the operating frequency band of the antenna element 200 that is lower than the frequency that enhances the gain, the combination of the first monopole antenna 210 or the second monopole antenna 220 with the first unfed element 300 is weakened, which can reduce the impact caused by the first unfed element 300. Additionally, the first element portion 310 can also be a polygon other than a quadrilateral, such as a triangle, pentagon, hexagon, or octagon. The same applies to the second element portion 320.

[0054] The first unfed element 300 may be made of sheet metal, for example. Alternatively, the first unfed element 300 may also be a conductive pattern. For example, if a retainer such as a resin retainer holding the antenna element 200 is provided on the first substrate 112, the sheet metal constituting the first unfed element 300 may be supported by the retainer, or the conductive pattern constituting the first unfed element 300 may be formed on the retainer. Alternatively, the first unfed element 300 may be provided on the antenna housing 600.

[0055] The second antenna section 14 includes a second substrate 114 and a first satellite antenna 410.

[0056] The first satellite antenna 410 is mounted on a second substrate 114 disposed on the antenna base 100. The first satellite antenna 410 is, for example, a GNSS (Global Navigation Satellite System) antenna. The second substrate 114 is, for example, a PCB. The first satellite antenna 410 is a patch antenna. The first satellite antenna 410 is positioned in front of the antenna element 200.

[0057] The third antenna section 16 includes a third substrate 116, a second satellite antenna 420, and a second unfed element 422.

[0058] The second satellite antenna 420 is mounted on a third substrate 116 disposed on the antenna base 100. The second satellite antenna is, for example, an SXM (Sirius XM) antenna. The third substrate 116 is, for example, a PCB. The second satellite antenna 420 is a patch antenna. The second satellite antenna 420 is positioned in front of the first satellite antenna 410. A second unfed element 422 is disposed on the second satellite antenna 420.

[0059] The fourth antenna section 18 includes an AM / FM (Amplitude Modulation / Frequency Modulation) broadcast antenna 500, a first holder 512, and a second holder 522.

[0060] The AM / FM radio broadcast antenna 500 includes a helical element 510 and a capacitor-loaded element 520. The helical element 510 is wound along a groove in a first retainer 512 provided on the antenna base 100, or held in place by a protrusion on the first retainer 512. The capacitor-loaded element 520 is held by a second retainer 522 connected to the first retainer 512. The helical element 510 and the capacitor-loaded element 520 are electrically connected to each other. The AM / FM radio broadcast antenna 500 is capable of receiving AM / FM broadcasts via the helical element 510 and the capacitor-loaded element 520. The AM / FM radio broadcast antenna 500 only needs to be able to receive at least one of AM and FM radio broadcasts.

[0061] Furthermore, as detailed in Embodiment 2 below, the first unfed element 300 can also function as part of the AM / FM broadcast antenna 500. In this case, the first unfed element 300 can be connected to the capacitive loading element 520 via a filter that cuts off the frequency at which the gain of the first unfed element 300 increases, such as a notch filter and a low-pass filter. By providing this filter, the first unfed element 300 can become part of the capacitive loading element constituting the AM / FM broadcast antenna 500. This allows for an increase in the size (area) of the capacitive loading element of the AM / FM broadcast antenna 500, thereby improving the performance of the AM / FM broadcast antenna 500. Alternatively, the rear portion of the second holder 522 can be extended rearward, and the first unfed element 300 can be mounted on this extended portion of the second holder 522.

[0062] In this embodiment, the first antenna section 12, the second antenna section 14, and the third antenna section 16 are formed using different substrates. However, it is also possible that at least two of the first antenna section 12, the second antenna section 14, and the third antenna section 16 are formed using the same substrate.

[0063] Figure 2This is a perspective view of the comparative example vehicle-mounted antenna device 10K. The comparative example vehicle-mounted antenna device 10K is the same as the vehicle-mounted antenna device 10A of Embodiment 1, except that the point where the first unfed element 300 is provided is not provided.

[0064] Figure 3 This is a diagram showing the radiation pattern of the first monopole antenna 210 of the vehicle-mounted antenna device 10A according to Embodiment 1 at a frequency of 6 GHz. Figure 4 This is a diagram showing the radiation pattern of the first monopole antenna 210 of the comparative example vehicle-mounted antenna device 10K at a frequency of 6 GHz. Figure 5 This is a diagram showing the radiation pattern of the second monopole antenna 220 of the vehicle-mounted antenna device 10A in Embodiment 1 at a frequency of 6 GHz. Figure 6 This is a diagram showing the radiation pattern of the second monopole antenna 220 of the comparative example vehicle-mounted antenna device 10K at a frequency of 6 GHz.

[0065] Figures 3 to 6 The first direction X, the second direction Y, and the third direction Z shown are related to... Figure 1 as well as Figure 2 The same applies to the first direction X, the second direction Y, and the third direction Z. Furthermore, Figures 3 to 6 In the diagram, the white circle with a black dot representing the second direction Y indicates the positive direction of the second direction Y when viewed from the inside of the paper towards the front, and the negative direction of the second direction Y when viewed from the front of the paper towards the inside.

[0066] In each figure, the azimuth (unit: deg) is represented by a radially extending dashed line from the center of the figure. Additionally, the gain (unit: dBi) is represented by concentrically extending dashed lines relative to the center of the figure.

[0067] If comparison Figure 3 as well as Figure 4 Therefore, the negative upward gain of the first direction X in the horizontal plane direction of the first monopole antenna 210 in Embodiment 1 is greater than the negative upward gain of the first direction X in the horizontal plane direction of the first monopole antenna 210 in the Comparative Example. This result suggests that the negative upward gain of the first direction X of the first monopole antenna 210 at a frequency of 6 GHz is improved by using the first unfed element 300.

[0068] If comparison Figure 5 as well as Figure 6 Therefore, the negative upward gain of the second monopole antenna 220 in the horizontal plane direction of the first direction X in Embodiment 1 is greater than the negative upward gain of the second monopole antenna 220 in the horizontal plane direction of the comparative example. This result suggests that the negative upward gain of the second monopole antenna 220 in the first direction X at a frequency of 6 GHz is improved by using the first unfed element 300.

[0069] Figure 7 This is a graph showing the frequency characteristics of the first monopole antenna 210 of the vehicle-mounted antenna device 10A of Embodiment 1 in the horizontal direction and the first monopole antenna 210 of the vehicle-mounted antenna device 10K of the comparative example in the horizontal direction from 1.5 GHz to 6 GHz. Figure 8 This is a graph showing the frequency characteristics of the second monopole antenna 220 of the vehicle-mounted antenna device 10A in the horizontal plane direction and the second monopole antenna 220 of the vehicle-mounted antenna device 10K in the comparative example, from 1.5 GHz to 6 GHz.

[0070] Figure 7 as well as Figure 8 In the graph, the horizontal axis represents frequency (unit: MHz). The vertical axis represents the average gain in the horizontal direction (unit: dBi).

[0071] like Figure 7 As shown, the average gain of the first monopole antenna 210 in the horizontal direction at frequencies of 5.5 GHz to 6.0 GHz in Embodiment 1 is higher than that of the first monopole antenna 210 in the comparative example in the same horizontal direction. This result suggests that the average gain of the first monopole antenna 210 in the horizontal direction at frequencies of 5.5 GHz to 6.0 GHz is improved by using the first unfed element 300.

[0072] like Figure 8 As shown, the average gain of the second monopole antenna 220 in the horizontal direction at frequencies of 5.5 GHz to 6.0 GHz in Embodiment 1 is higher than that of the second monopole antenna 220 in the comparative example in the same frequency range. This result suggests that the average gain of the second monopole antenna 220 in the horizontal direction at frequencies of 5.5 GHz to 6.0 GHz is improved by using the first unfed element 300.

[0073] Figure 9 This is a perspective view of the vehicle-mounted antenna device 10B according to Embodiment 2. The vehicle-mounted antenna device 10B according to Embodiment 2 is the same as the vehicle-mounted antenna device 10A according to Embodiment 1, except for the following points.

[0074] The first unfed element 300 functions as part of the AM / FM broadcast antenna 500. Specifically, the vehicle-mounted antenna device 10B includes a first connecting conductor 532, a second connecting conductor 534, a first filter 542, a second filter 544, a third filter 546, and a fourth filter 548.

[0075] The first connecting conductor 532 and the second connecting conductor 534 are arranged along the left-right direction of the vehicle-mounted antenna device 10B. When viewed from the rear of the vehicle-mounted antenna device 10B, the first connecting conductor 532 is located on the left relative to the second connecting conductor 534. When viewed from the rear of the vehicle-mounted antenna device 10B, the second connecting conductor 534 is located on the right relative to the first connecting conductor 532. The first connecting conductor 532 and the second connecting conductor 534 are located between the first unfed element 300 and the capacitor loading element 520 in the front-rear direction of the vehicle-mounted antenna device 10B.

[0076] The first element portion 310 and the left side portion of the capacitor loading element 520 are electrically connected to each other via the first filter 542, the first connecting conductor 532, and the second filter 544. Specifically, the rear end of the first connecting conductor 532 and the front end of the first element portion 310 are electrically connected to each other via the first filter 542. The front end of the first connecting conductor 532 and the rear end of the left side portion of the capacitor loading element 520 are electrically connected to each other via the second filter 544.

[0077] The second element portion 320 and the right side portion of the capacitor loading element 520 are electrically connected to each other via the third filter 546, the second connecting conductor 534, and the fourth filter 548. Specifically, the rear end of the second connecting conductor 534 and the front end of the second element portion 320 are electrically connected to each other via the third filter 546. The front end of the second connecting conductor 534 and the rear end of the right side portion of the capacitor loading element 520 are electrically connected to each other via the fourth filter 548.

[0078] The first filter 542, the second filter 544, the third filter 546, and the fourth filter 548 are each low-pass filters. Therefore, the first unfed element 300 and the capacitor-loaded element 520 are electrically connected to each other via at least one low-pass filter. Thus, the first unfed element 300 can become part of the capacitor-loaded element constituting the AM / FM broadcast antenna 500. This allows for an increase in the size (area) of the capacitor-loaded element of the AM / FM broadcast antenna 500, thereby improving the performance of the AM / FM broadcast antenna 500.

[0079] Figure 10This is a graph showing the frequency response of the forward transfer coefficient S21 of the S-parameters of the first filter 542 from 0 to 7 GHz. The S-parameters of the first filter 542 are represented by four parameters: S11, S21, S12, and S22 in a two-terminal loop having port 1 and port 2. Parameter S11 is the reflection coefficient of the signal input from port 1 and reflected from port 1. Parameter S21 is the transmission coefficient of the signal input from port 1 and transmitted through port 2, that is, the forward transfer coefficient. Parameter S12 is the transmission coefficient of the signal input from port 2 and transmitted through port 1, that is, the reverse transfer coefficient. Parameter S22 is the reflection coefficient of the signal input from port 2 and reflected from port 2.

[0080] Figure 10 In the graph, the horizontal axis represents frequency (unit: MHz). The vertical axis represents the absolute value of the forward transfer coefficient S21 (unit: dB).

[0081] like Figure 10 As shown, the absolute value of the forward transfer factor S21 in the FM band around 98MHz is approximately -0.2dB. On the other hand, the absolute value of the forward transfer factor S21 in the telephone (TEL) band from 1.7GHz to 6GHz is approximately -10dB or less. Therefore, the first filter 542 can allow the FM band signal to pass through by comparing it with the TEL band signal. In addition, the first filter 542 can cut off the frequency at which the gain of the first monopole antenna 210 or the second monopole antenna 220, such as 5.5GHz to 6GHz, is increased by the first unfed element 300.

[0082] The second filter 544, the third filter 546, and the fourth filter 548 also have the same characteristics as those used in... Figure 10 The characteristics of the first filter 542 described are the same.

[0083] Figure 11 This is a graph showing the average gain of the first monopole antenna 210 in the horizontal direction of the vehicle-mounted antenna device 10A of Embodiment 1, the average gain of the first monopole antenna 210 in the horizontal direction of the vehicle-mounted antenna device 10B of Embodiment 2, and the average gain of the first monopole antenna 210 in the horizontal direction of the vehicle-mounted antenna device 10K of the comparative example, from 1.5 GHz to 6 GHz. Figure 12 This is a graph showing the frequency characteristics of the second monopole antenna 220 in the horizontal plane direction of the vehicle-mounted antenna device 10A of Embodiment 1, the second monopole antenna 220 in the horizontal plane direction of the vehicle-mounted antenna device 10B of Embodiment 2, and the second monopole antenna 220 in the horizontal plane direction of the comparative example vehicle-mounted antenna device 10K from 1.5 GHz to 6 GHz. Figure 13This is a graph showing the average gain in the horizontal direction of the AM / FM broadcasting antenna 500 of the vehicle-mounted antenna device 10B of Embodiment 2 and the average gain in the horizontal direction of the AM / FM broadcasting antenna 500 of the vehicle-mounted antenna device 10K of the Comparative Example, from 80MHz to 120MHz.

[0084] Figures 11 to 13 In the embodiments, the vehicle-mounted antenna device 10A of Embodiment 1, the vehicle-mounted antenna device 10B of Embodiment 2, and the vehicle-mounted antenna device 10K of the comparative example are disposed on a ground plane extending to infinity.

[0085] Figures 11 to 13 In the graph, the horizontal axis represents frequency (unit: MHz). The vertical axis represents the average gain in the horizontal direction (unit: dBi).

[0086] like Figure 11 As shown, in the full frequency range of 5.5 GHz to 6.0 GHz, the average gain of the first monopole antenna 210 in the horizontal plane direction of Embodiment 1 and Embodiment 2 is higher than that of the first monopole antenna 210 in the comparative example. Furthermore, in the frequency range of 5.5 GHz to 6.0 GHz, the average gain of the first monopole antenna 210 in the horizontal plane direction of Embodiment 2 is approximately the same as that of the first monopole antenna 210 in the horizontal plane direction of Embodiment 1.

[0087] like Figure 12 As shown, in almost the entire frequency range of 5.5 GHz to 6.0 GHz, the average gain of the second monopole antenna 220 in the horizontal plane direction of Embodiment 1 and Embodiment 2 is higher than that of the second monopole antenna 220 in the comparative example. Furthermore, in the frequency range of 5.5 GHz to 6.0 GHz, the average gain of the second monopole antenna 220 in the horizontal plane direction of Embodiment 2 is approximately the same as that of the second monopole antenna 220 in Embodiment 1.

[0088] like Figure 13 As shown, in the full-band range of 80MHz to 120MHz, the average gain of the AM / FM broadcast antenna 500 of Embodiment 2 in the horizontal direction is higher than the average gain of the AM / FM broadcast antenna 500 of the Comparative Example in the horizontal direction.

[0089] according to Figure 13The results show that by electrically connecting the first unfed element 300 and the capacitor-loaded element 520 to each other via the first filter 542, the second filter 544, the third filter 546, and the fourth filter 548, the gain at frequencies of 80MHz to 120MHz, i.e., the FM band, can be increased. Furthermore, according to... Figure 11 as well as Figure 12 The results show that even when the first unpowered element 300 and the capacitor-loaded element 520 are electrically connected to each other via the first filter 542, the second filter 544, the third filter 546 and the fourth filter 548, there is almost no reduction in gain of 5.5 GHz to 6.0 GHz compared to the case where the first unpowered element 300 and the capacitor-loaded element 520 are not electrically connected to each other.

[0090] Figure 14 This is a perspective view of a modified vehicle-mounted antenna device 10G. The modified vehicle-mounted antenna device 10G is the same as the vehicle-mounted antenna device 10A of Embodiment 1, except for the following points.

[0091] The vehicle-mounted antenna device 10G includes a first unfed element 300G. The first unfed element 300G includes a first element portion 310G and a second element portion 320G. Unlike the first unfed element 300 of Embodiment 1, in this modified example, the first element portion 310G and the second element portion 320G are each quadrilaterals in which the length in the longitudinal direction of the vehicle-mounted antenna device 10G is shorter than the length of the vertical side of the vehicle-mounted antenna device 10G. In this modified example, similar to Embodiment 1, compared to the case where the first unfed element 300G is not provided, it is possible to miniaturize the vehicle-mounted antenna device 10G while ensuring gain in the horizontal direction of the high-frequency band.

[0092] The embodiments and variations of the present invention have been described above with reference to the accompanying drawings. However, these are merely illustrative examples of the present invention, and various configurations other than those described above are also possible.

[0093] For example, the shape, arrangement, and other conditions of the first unfed element 300 are not limited to those of the embodiments and variations. By adjusting the shape, arrangement, and other conditions of the first unfed element 300, the gain in a desired direction in a specific frequency band, such as a higher frequency band, can be improved.

[0094] The following methods are provided according to this instruction manual.

[0095] (Method 1)

[0096] Method 1 is a vehicle-mounted antenna device, which has:

[0097] Antenna base;

[0098] The antenna housing, together with the antenna base, forms a receiving space;

[0099] A monopole antenna housed within the housing space; and

[0100] An unfeeding element is positioned above the monopole antenna.

[0101] According to method 1, compared with the case of no feeding element, it is possible to ensure the gain in the desired direction of the high-frequency band while miniaturizing the antenna.

[0102] (Method 2)

[0103] Method 2 is the same as the vehicle-mounted antenna device described in Method 1.

[0104] The unfed element functions as a secondary radiating element.

[0105] According to method 2, the unfed element can function as an element that increases the gain of the monopole antenna in the desired direction at a specified frequency.

[0106] (Method 3)

[0107] Method 3 is the vehicle-mounted antenna device described in Method 1 or 2.

[0108] The monopole antenna is used for long-distance communication.

[0109] According to method 3, for antennas used in remote communication, similar to method 1, it is possible to ensure gain in the horizontal direction of the high-frequency band while miniaturizing the antenna.

[0110] (Method 4)

[0111] In the vehicle-mounted antenna device of any one of methods 1 to 3, method 3

[0112] It has multiple monopole antennas.

[0113] According to method 4, compared with the case where the vehicle-mounted antenna device has only a single monopole antenna, multiple monopole antennas can operate in the broadband domain.

[0114] (Method 5)

[0115] Method 5 is the vehicle-mounted antenna device according to any one of methods 1 to 4.

[0116] The unpowered element is composed of multiple element parts that are separated from each other.

[0117] According to method 5, compared to the case where the unpowered element consists of a single component, by placing multiple component components in appropriate positions, the gain can be significantly increased without a power-fed element. Furthermore, gain in the desired direction within the high-frequency band can be ensured.

[0118] (Method 6)

[0119] In the vehicle-mounted antenna device of any one of methods 1 to 5, method 6

[0120] The unfeeded element functions as part of a broadcast antenna.

[0121] According to method 6, compared to the case where the unfed element does not function as part of the broadcast antenna, the size (area) of the capacitive loading element of the broadcast antenna can be increased, thereby improving the performance of the broadcast antenna.

[0122] (Method 7)

[0123] In the vehicle-mounted antenna device of any one of methods 1 to 6, method 7 is...

[0124] When λ is set as the wavelength of the frequency in the operating frequency of the monopole antenna whose gain is enhanced by the unfeeded element, the distance between the end of the monopole antenna side without the feed element and the end of the monopole antenna side without the feed element is greater than or equal to λ / 2 - λ / 4 and less than or equal to λ / 2 + λ / 4.

[0125] According to method 7, when the distance between the end of the monopole antenna without a feeding element and the end of the monopole antenna without a feeding element is approximately λ / 2, compared with the case where the distance is significantly different from approximately λ / 2, the gain of the monopole antenna in the horizontal direction can be further enhanced by the absence of a feeding element.

[0126] This application claims priority based on Japanese Patent Application No. 2020-126223, filed on July 27, 2020, and all its disclosures are incorporated herein by reference.

[0127] Explanation of reference numerals in the attached figures

[0128] 10A Vehicle-Mounted Antenna Device

[0129] 10B Vehicle-Mounted Antenna Device

[0130] 10G vehicle-mounted antenna device

[0131] 10K vehicle-mounted antenna device

[0132] 12 First Antenna Section

[0133] 14. Second Antenna Section

[0134] 16. Third Antenna Section

[0135] 18. Fourth Antenna Section

[0136] 100 antenna base

[0137] 112 1st base plate

[0138] 114 2nd base plate

[0139] 116 3rd substrate

[0140] 200 antenna vibrator

[0141] 210 First Monopole Antenna

[0142] Component 1 of 212

[0143] Component 214

[0144] 216 Port 1

[0145] 220 second monopole antenna

[0146] Component 3 of 222

[0147] 224 Component 4

[0148] 226 Port 2

[0149] 300 No. 1 No-feed element

[0150] 300G No-feed element

[0151] 310 Component 1

[0152] 310G Component 1

[0153] 320 Component 2

[0154] 320G Component 2

[0155] 410 First Satellite Antenna

[0156] 420 Second Satellite Antenna

[0157] 422 No-feed element

[0158] Antenna for 500AM / FM radio broadcasting

[0159] 510 spiral element

[0160] 512 First Cage

[0161] 520 Capacitor Loading Component

[0162] 522 Second Cage

[0163] 532 First Connector

[0164] 534 Second Connector

[0165] 542 First Filter

[0166] 544 Filter No. 2

[0167] 546 Third Filter

[0168] Filter 4 of 548

[0169] 600 antenna housing

[0170] X-direction 1

[0171] Y 2nd direction

[0172] Z in the third direction.

Claims

1. An antenna device for a vehicle, characterized by comprising: have: Antenna base; The antenna housing, together with the antenna base, forms a receiving space; A monopole antenna housed within the aforementioned housing space; An unfeeding element is positioned above the monopole antenna; and Antennas equipped with capacitive loading elements, The unpowered element and the capacitively loaded element are electrically connected to each other via a filter.

2. The vehicle-mounted antenna device according to claim 1, characterized in that, The unfed element functions as a secondary radiating element.

3. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The monopole antenna is used for long-distance communication.

4. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, It has multiple monopole antennas.

5. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The unpowered element is composed of multiple element parts that are separated from each other.

6. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The unfeeded element functions as part of a broadcast antenna.

7. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, When λ is set as the wavelength of the frequency in the operating frequency of the monopole antenna whose gain is enhanced by the unfeeded element, the distance between the end of the monopole antenna side without the feed element and the end of the monopole antenna side without the feed element is greater than λ / 2 - λ / 4 and less than λ / 2 + λ / 4.

8. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The monopole antenna is U-shaped.

9. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The downward projection of the unfed element overlaps with at least a portion of the monopole antenna.

10. The vehicle-mounted antenna device according to claim 1 or 2, characterized in that, The unfed element functions as part of the antenna.

Images