GB2481926A

GB2481926A - Antenna device for vehicle window

Info

Publication number: GB2481926A
Application number: GB1113795.7A
Authority: GB
Inventors: Noriyuki Mukai; Shinji Iino
Original assignee: Harada Industry Co Ltd
Current assignee: Harada Industry Co Ltd
Priority date: 2009-02-12
Filing date: 2010-02-10
Publication date: 2012-01-11
Also published as: GB201113795D0; WO2010092983A1; JPWO2010092983A1; BRPI1008748A2; JP5485184B2

Abstract

Disclosed is an antenna device for a vehicle window with which impedance matching can easily be achieved, while an antenna element of small size and simple pattern is achieved. The antenna device for a vehicle window is provided with a ground pattern (17), a power supply terminal (20) and an antenna element (30). The ground pattern (17) has a ground terminal and a loop-shaped section and is arranged practically parallel with the edge of the vehicle body. The power supply terminal (20) is arranged close to the ground pattern (17). The antenna element (30) extends from the power supply terminal (20) in the vertical direction with respect to the ground pattern (17). A plurality of bridge patterns (14) that are parallel with the antenna element (30) are provided on the inside of the loop-shaped ground pattern (17).

Description

D ESC RI PTI ON

ANTENNA DEVICE FOR VEHICLE WINDOW

Technical Field

[0001] The present invention relates to an antenna device for a vehicle window, and more particularly to an ungrounded antenna device for a vehicle window.

Background Art

[0002] An antenna provided on a vehicle window is roughly divided into two types: a glass antenna and a film antenna. The glass antenna is one obtained by previously printing an antenna wire on a glass. The film antenna is obtained by adhesively sticking an adhesive film on which an antenna element is patterned to a glass. Further, as the film antenna, there exists one obtained by a first step of adhering an antenna element with adhesive layer patterned on a film to a vehicle window made of a glass or the like and a second step of peeling off the film so as to leave only the antenna element on the glass or the like. In the present specification, the term "antenna device for a vehicle window" is assumed to include the glass antenna, film antenna, antenna having a configuration in which only an antenna element is left in the installation site, and the like. Various types (e.g, for front window, for rear window, for side window, and the like) of such antenna devices exist depending on the type of the window on which the antenna devices are installed.

[0003] Further, there exist a grounded antenna device for a vehicle window in which grounding is required for a vehicle body such as a roof or pillar, and exist an ungrounded antenna device for a vehicle window in which electrical connection between the vehicle body and the antenna device is not required.

As to the antenna device for a vehicle window, the ungrounded antenna device is superior to the grounded antenna device in which grounding is required for a vehicle body in terms of workability of installation to a vehicle.

[0004] For example, Patent Document 1 discloses such an ungrounded antenna device. Patent Document 1 discloses an ungrounded monopole antenna device composed of a monopole antenna element and L-shaped ground elements arranged on both sides of the monopole antenna element.

[Citation List] [Patent Document] [0005] Patent Document 1: Japanese Patent Application Kokai Publication No. 2003-110342

Disclosure of the Invention

Problems to be Solved by the Invention [0006] However, in the antenna device disclosed in Patent Document 1, it is difficult to achieve impedance matching with a cable. Further, there is no flexibility in the design of the shape of a ground pattern, so that there is not much adjustment.

[0007] In view of the above situation, an object of the present invention is to provide an antenna device for a vehicle window in which impedance matching can easily be achieved and there is much adjustment while an antenna element with small size and simple pattern is achieved.

Means for Solving the Problems [0008] To attain the above object of the present invention, an antenna device for a vehicle window comprises: a ground pattern disposed in substantially parallel to a vehicle body edge portion and having a ground terminal and a loop-shaped portion; a power feeding terminal disposed near the ground pattern; and an antenna element extending in the perpendicular direction with respect to the ground pattern from the power feeding terminal.

[0009] The ground pattern may have, inside the loop-shaped portion, a plurality of bridge patterns arranged in parallel to the antenna element.

[0010] The ground pattern may have at least one gap in the loop-shaped portion.

[001 1] The antenna element may have two patterns extending in parallel in the perpendicular direction with respect to the ground pattern from the power feeding terminal.

[0012] End portions of the two patterns constituting the antenna element may be connected to each other.

[0013] The power feeding terminal may be disposed near the center of the ground pattern in longitudinal direction thereof.

[0014] The ground pattern may be disposed so as to surround a part of the power feeding terminal with a predetermined interval from the power feeding terminal.

[0015] The ground pattern may further have a linear pattern extending in parallel to the longitudinal direction of the ground pattern from the ground terminal.

[0016] The loop-shaped portion of the ground pattern may be disposed at a location near an end portion of the ground pattern away from the power feeding terminal.

Advantages of the invention [0017] The antenna device for a vehicle window according to the present invention has an advantage that impedance matching can easily be achieved while an antenna element with small size and simple pattern is achieved.

Further, it is possible to easily adjust antenna characteristics.

Brief Description of the Drawings

[0018] FIG. 1 is a schematic plan view for explaining an antenna device for a vehicle window according to a first embodiment of the present invention.

FIG. 2 is a schematic plan view for explaining another arrangement example of a power feeding terminal of the antenna device for a vehicle window according to the present invention.

FIG. 3 is a schematic plan view for explaining still another arrangement example of a power feeding terminal of the antenna device for a vehicle window according to the present invention.

FIG. 4 is a schematic plan view for explaining an antenna device for a vehicle window according to a second embodiment of the present invention.

FIG. 5 is a schematic plan view for explaining an antenna device for a vehicle window according to a third embodiment of the present invention.

FIG. 6 is a schematic plan view for explaining an example in which a ground pattern has two gaps in the antenna device for a vehicle window according to the third embodiment of the present invention.

FIG. 7 is a frequency vs. sensitivity characteristic graph for comparing the antenna device for a vehicle window illustrated in FIG. 4 and antenna device for a vehicle window illustrated in FIG. 6 in terms of the reception performance.

FIG. 8 is a schematic plan view for explaining an example in which the antenna element is constituted by two patterns in the antenna device for a vehicle window according to the present invention.

FIG. 9 is a schematic plan view for explaining an example in which the end portions of two patterns of the antenna element are connected to each other to constitute a loop in the antenna device for a vehicle window according to the present invention.

FIG. 10 is a schematic plan view for explaining an antenna device for a vehicle window according to a fourth embodiment of the present invention.

Preferred Embodiments of the Invention [0019] Preferred embodiments for practicing the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic plan view for explaining an antenna device for a vehicle window according to a first embodiment of the present invention. As illustrated, the antenna device for a vehicle window according to the present invention is composed of a ground pattern 10, a power feeding terminal 20, and an antenna element 30.

[0020] As illustrated, the ground pattern 10 has a ground terminal 11 and a loop-shaped portion. The ground side of a connector 1 for connecting to an external device (not illustrated) through a cable is connected to the ground terminal 11. The antenna device for a vehicle window according to the present invention is installed on a vehicle window such that the ground pattern 10 extends in substantially parallel to the edge portion of a vehicle body R such as a roof or a pillar. A retreated portion is formed in the ground pattern 10 of the illustrated example so as to surround a part of the power feeding terminal with a predetermined interval from the power feeding terminal 20. In the illustrated example, the retreated portion is formed near the center portion of the ground pattern 10 in the longitudinal direction thereof.

[0021] Although the ground terminal 11 is provided on the left side of the power feeding terminal 20 in the illustrated example, the present invention is not limited to this, but the ground terminal may be provided on the right side of the power feeding terminal. Further, a configuration may be possible in which ground terminals are provided on both sides of the power feeding terminal such that the power feeding terminal is interposed between the ground terminals. This makes the antenna pattern symmetric. With the symmetric antenna pattern, in the case where the antenna device of the present invention is used to realize a diversity antenna and where two antenna devices are installed on the left and right sides of the a vehicle window, a connector cable can be withdrawn from either left or right side of one antenna pattern.

[0022] The power feeding terminal 20 is disposed near the ground pattern 10 and, in the illustrated example, it has substantially a square shape. The power feeding terminal 20 is disposed so as to be fitted into the abovementioned retreated portion of the ground pattern 10 with a predetermined interval from the ground pattern 10. Thus, the ground pattern 10 is disposed so as to surround a part of the power feeding terminal 20 with a predetermined interval from the power feeding terminal 20. Further, in the illustrated example, the ground pattern 10 is symmetrically disposed with respect to the power feeding terminal 20. The power feeding terminal 20 is connected to the hot side of the connector 1 and is thereby connected to an external device (not illustrated) through a cable.

[0023] The antenna element 30 extends from the power feeding terminal 20.

The antenna element 30 of the illustrated example is a monopole antenna element, which is electrically connected to the power feeding terminal 20 and extends in the perpendicular direction with respect to the longitudinal direction of the ground pattern 10. With this configuration, the antenna device for a vehicle window is formed into a T-shape. Note that the term "perpendicular direction" does not necessarily signify "strict perpendicular direction" and may include "substantially perpendicular direction".

[0024] In the case where the antenna device for a vehicle window of the present invention having the configuration described above is used to realize a film antenna, a conductive thin-film is disposed on a film. That is, a conductive thin-film is disposed on a film 2 in the illustrated pattern so as to constitute the ground pattern 10, the power feeding terminal 20, and the antenna element 30. The conductive thin-film corresponding to the ground terminal 11 and power feeding terminal 20 is exposed so as to electrically be connected to the connector, and the other part of the conductive thin-film is coated with a film or the like.

[0025] According to the configuration of the present invention, it is possible to realize an antenna device for a vehicle window with a small size and simple antenna pattern enough to make it difficult to obstruct a driver's view.

Further, the adoption of the loop-shaped ground pattern apparently increases the size of the ground, so that even with the ungrounded antenna device, it is possible to obtain sufficient antenna performance in the frequency band, for example, for terrestrial digital broadcasting.

[0026] Although the power feeding terminal is disposed so as to be surrounded by the retreated portion of the ground pattern in the antenna device for a vehicle window according to the first embodiment illustrated in FIG. 1, the present invention is not limited to this but it is only necessary for the power feeding terminal to be disposed near the ground pattern. FIG. 2 is a schematic plan view for explaining another arrangement example of the power feeding terminal of the antenna device for a vehicle window according to the present invention. In FIG. 2, parts designated by the same reference numerals as those in FIG. 1 are substantially identical with those of the same reference numerals shown in FIG. 1, and repetitive explanation will be omitted.

[0027] In the example illustrated in FIG. 2, the retreated portion is not formed in the ground pattern 10, but a protruded ground terminal 12 is provided inside the loop-shaped pattern. The power feeding terminal 20 is provided near the protruded ground terminal 12. As described above, in the antenna device for a vehicle window according to the present invention, the ground pattern has the loop-shaped portion, so that the use of the inside area of the loop-shaped portion allows various modifications.

[0028] Further, although the power feeding terminal is disposed near the center of the ground pattern in the longitudinal direction thereof in the antenna device for a vehicle window s of FIGS. 1 and 2, the present invention is not limited to this, but the power feeding terminal may be disposed near the edge portion of the ground pattern. FIG. 3 is a schematic plan view for explaining still another arrangement example of the power feeding terminal of the antenna device for a vehicle window according to the present invention. In FIG. 3, parts designated by the same reference numerals as those in FIG. 1 are substantially identical with those of the same reference numerals shown in FIG. 1, and repetitive explanation will be omitted.

[0029] In the example of FIG. 3, a ground terminal 13 of the ground pattern 10 is provided at the edge portion of the loop-shaped portion, and the power feeding terminal 20 is disposed near the edge portion. Although the power feeding terminal 20 is disposed near the right side of the ground terminal 13 in the illustrated example, the present invention is not limited to this, but the power feeding terminal 20 may be disposed, e.g., near the lower side of the ground terminal 13.

[0030] As described above, in the antenna device for a vehicle window according to the present invention, the power feeding terminal is disposed near the ground pattern having the loop-shaped portion, and the antenna element is disposed in the perpendicular direction with respect to the ground pattern.

[0031] An antenna device for a vehicle window according to a second embodiment of the present invention will next be described with reference to FIG. 4. FIG. 4 is a schematic plan view for explaining an antenna device for a vehicle window according to a second embodiment of the present invention.

In FIG. 4, parts designated by the same reference numerals as those in FIG. 1 are substantially identical with those of the same reference numerals shown in FIG. 1.

[0032] As illustrated, in the antenna device for a vehicle window according to the second embodiment, a ground pattern 17 has, inside the loop-shaped portion, a plurality of bridge patterns 14 arranged in the direction parallel to the antenna element 30. In the antenna device for a vehicle window of the illustrated example, the ground pattern 17 is symmetrically disposed with respect to the power feeding terminal 20. Two ground terminals 15 and 16 are provided in the ground pattern 17, and the power feeding terminal 20 is disposed between the ground terminals 15 and 16. This makes the antenna pattern symmetric. This allows a connector cable to be withdrawn from either left or right side of one antenna pattern.

[0033] The antenna device for a vehicle window according to the second embodiment of the present invention is not limited to the illustrated example, but the number of the bridge patterns, the width of each of the bridge patterns, and the symmetric property of the antenna pattern may be changed as needed.

[0034] By providing the bridge patterns inside the loop-shaped portion of the ground pattern as in the second embodiment of the present invention, adjustment of various characteristics such as receiver sensitivity characteristics, VSWR characteristics, and antenna characteristics can be made. For example, it is possible to perform adjustment so as to increase the receiver sensitivity or reduce VSWR for reducing impedance mismatch by increasing/decreasing the number of the bridge patterns or changing the line width of the pattern.

[0035] An antenna device for a vehicle window according to a third embodiment of the present invention will next be described with reference to FIG. 5. FIG. 5 is a schematic plan view for explaining an antenna device for a vehicle window according to a third embodiment of the present invention. In FIG. 5, parts designated by the same reference numerals as those in FIG. 4 are substantially identical with those of the same reference numerals shown in FIG. 4. In the antenna device for a vehicle window according to the third embodiment, the loop-shaped portion of the ground pattern has at least one gap.

[0036] As illustrated, one gap 19 is provided in the loop-shaped portion of the ground pattern 18. In the antenna device for a vehicle window according to the first embodiment illustrated in FIG. 1, the loop-shaped portion of the ground pattern is formed into a closed loop, so that the line length of the ground pattern corresponds to the length of the ground pattern from its one side to the other. However, as in the antenna device for a vehicle window according to the third embodiment, when the gap 19 is provided at one portion of the loop-shaped portion of the ground pattern 18, e.g., near the center of the upper side of the loop-shaped portion in FIG. 5, the lines of the ground pattern 18 extending from the left and right ground terminals 15 and 16 are folded back, whereby the total line length of the ground pattern 18 is increased. As a result, it is possible to improve antenna characteristics in the low-frequency band, Further, the antenna characteristics can easily be adjusted by adjusting the width of the gap, thereby easily achieving impedance matching.

[0037] Although the one gap is formed in the example of FIG. 5, the present invention is not limited to this, but a plurality of gaps may be provided. FIG. 6 is a schematic plan view illustrating an example in which the ground pattern has two gaps in the antenna device for a vehicle window according to the third embodiment of the present invention. In FIG. 6, parts designated by the same reference numerals as those in FIG. 5 are substantially identical with those of the same reference numerals shown in FIG. 5, and repetitive explanation will be omitted. As illustrated, even in the case where two gaps 19 and 19 are provided, the line length of the ground pattern can be adjusted as in the example illustrated in FIG. 5. As described above, according to the antenna device for a vehicle window of the third embodiment, a gap is provided in the loop-shaped portion of the ground pattern, which makes it easy to adjust antenna characteristics and easy to achieve impedance matching.

[0038] Here, the antenna device for a vehicle window according to the second embodiment illustrated in FIG. 4 and the antenna device for a vehicle window according to the third embodiment illustrated in FIG. 6 are compared with each other in terms of sensitivity characteristics. FIG. 7 is a frequency vs. sensitivity characteristic graph for comparing the antenna device for a vehicle window illustrated in FIG. 4 and the antenna device for a vehicle window illustrated in FIG. 6 in terms of the reception performance.

[0039] As can be seen from FIG. 7, the both antenna devices for a vehicle window exhibit equivalent characteristics on the high-frequency side of the frequency band for terrestrial digtaI broadcasting, or the sensitivity of the antenna device for a vehicle window illustrated in FIG. 4 is slightly higher. On the other hand, on the low-frequency side of the frequency band for terrestrial digital broadcasting, the sensitivity characteristics significantly differ between the two antenna devices. That is, the antenna device for a vehicle window illustrated in FIG. 6 exhibits more significant improvement in the sensitivity characteristics on the low-frequency side, This is convenient because it is possible to obtain improvement in the sensitivity characteristics in the low band used in, eg., an area of high population density.

[0040] In general, it can be considered to increase the length of the antenna element in order to improve the sensitivity characteristics in the low-frequency band. However, in the case of the antenna device for a vehicle window, the length of the antenna element cannot be increased above a certain value in view of the adverse effect on the driver's view or under regulations. However, as described above, it is possible to improve antenna characteristics in the low-frequency band in the antenna device for a vehicle window of the present invention, so that the antenna characteristics can easily be adjusted without need of increasing the length of the and portion of the antenna element that may obstruct the driver's view.

[0041] Although one line pattern that extends in the perpendicular direction from the power feeding terminal is illustrated as the antenna element in the above description, the present invention is not limited to this, but the antenna element may be constituted by two patterns extending in parallel from the power feeding terminal. FIG. 8 is a schematic plan view for explaining an example in which the antenna element is constituted by two patterns in the antenna device for a vehicle window according to the present invention. In FIG. 8, parts designated by the same reference numerals as those in FIG. 1 are substantially identical with those of the same reference numerals shown in FIG. 1, and the basic configuration illustrated in FIG. 8 is the same as that illustrated in FIG. 1. As illustrated in FIG. 8, the antenna element is constituted by two patterns, i.e., first and second antenna elements 32 and 33, extending in parallel from the power feeding terminal 20.

[0042] Even in the case where such an antenna element is adopted in the antenna device for a vehicle window according to the present invention, it is possible to obtain the same effect as that in the examples described above. -11 -

When the first and second antenna elements 32 and 33 extending in parallel from the power feeding terminal 20 are used to constitute the antenna element, the antenna element behaves substantially equivalent to one thick strip-like antenna element. Therefore, the surface area can be reduced as compared to the strip-shaped antenna element, making it more difficult to obstruct a driver's view.

[0043] Further, by changing the lengths of the first and second antenna elements 32 and 33, antenna characteristics can be adjusted. For example, by reducing the lengths of the first and second antenna elements 32 and 33, characteristics in the high-frequency band can be improved.

[0044] Although the antenna element is constituted by two patterns in FIG. 8, the present invention is not limited to this, FIG. 9 is a schematic plan view for explaining an example in which the end portions of two patterns of the antenna element are connected to each other to constitute a loop in the antenna device for a vehicle window according to the present invention. In FIG. 9, parts designated by the same reference numerals as those in FIG. 8 are substantially identical with those of the same reference numerals shown in FIG. 8, and the basic configuration illustrated in FIG. 9 is the same as that illustrated in FIG. 8.

As illustrated in FIG. 9, the end portions of two patterns of an antenna element 35 extending in parallel from the power feeding terminal 20 are connected to [0045] Even in the case where the antenna element is configured as described above in the antenna device for a vehicle window according to the present invention, it is possible to obtain the same effect as in the examples described above. Further, by forming the antenna element into a loop, the coupling amount between the patterns is increased by the connection. As a result, further gain improvement can be achieved. Therefore, it is possible to improve antenna characteristics while suppressing adverse effect on the driver's view. Further, the following configuration may be allowable: the antenna element is designed to have two patterns, the end portions of the -12-antenna elements are reduced for adjustment of characteristics, and the end portion thereof are connected in the final stage of design. This allows easy achievement of gain improvement.

[0046] An antenna device for a vehicle window according to a fourth embodiment of the present invention will next be described with reference to FIG. 10. FIG. 10 is a schematic plan view for explaining an antenna device for a vehicle window according to a fourth embodiment of the present invention.

In FIG. 10, parts designated by the same reference numerals as those in FIG. 3 are substantially identical with those of the same reference numerals shown in FIG. 3. In the antenna device for a vehicle window according to the fourth embodiment, a linear pattern is added to the ground pattern.

[0047] As illustrated, in the antenna device for a vehicle window according to the fourth embodiment of the present invention, a linear pattern 41 is provided extending from a ground terminal 40 in parallel to the longitudinal direction of the ground pattern 10. In the illustrated example, the linear pattern 41 extends directly from the ground terminal 40 to the left direction in parallel to the longitudinal direction of the ground pattern 10. However, the present invention is not limited to this, but for example, the linear pattern 41 may be formed in an L-shape such that it extends once in the lower direction, folded by 90 degrees to the left, and extends in the left direction. Further, in the illustrated example, the loop-shaped portion of the ground pattern 10 is disposed at a location near the end portion of the ground pattern 10 away from the power feeding terminal 20. That is, the loop-shaped portion extends in a a-shape from the ground terminal 40. However, the present invention is not limited to this, but the arrangement as illustrated in FIG. 1 in which the ground terminal and the power feeding terminal are disposed near the center of the ground pattern in the longitudinal direction thereof may be adopted. That is, it is only necessary that the linear pattern extend in the longitudinal direction of the ground pattern. Further, in the illustrated example, the power feeding terminal 20 is disposed near the right side of the ground terminal 40, and the -13-ground pattern is disposed so as to surround the power feeding terminal 20.

Further, the end portions of the two patterns extending in parallel from the power feeding terminal 20 are connected to each other to constitute the loop-shaped antenna element 35. However, the present invention is not limited to this, but the end portions of the two patterns may be opened, or the antenna element may be constituted by one wire.

[0048] In the antenna device for a vehicle window according to the fourth embodiment of the present invention, the ground terminal 40, the power feeding terminal 20, and the linear pattern 41 are covered by the connector 1.

By making the linear pattern extend in parallel to the longitudinal direction of the ground pattern from the ground terminal, the linear pattern is covered by the connector and disposed along the connector. With this configuration, it is possible to further improve antenna characteristics on the low-frequency side of the frequency band for terrestrial digital broadcasting.

[0049] The width of the linear pattern is not limited to that in the illustrated example but may be thinner or thicker. Similarly, the length of the linear pattern is not limited to that in the illustrated example but may be shorter or longer.

[0050] As described above, in the antenna device for a vehicle window according to the present invention, by providing the bridge patterns in the loop-shaped portion of the ground pattern, by providing the gap, or by making the linear pattern extend from the ground terminal, it is possible to improve characteristics in the high-frequency band by means of the antenna element while improving characteristics in the low-frequency band. Thus, the antenna device in which gain is improved over a wide band can be obtained.

[0051] The antenna device for a vehicle window according to the present invention is not limited to the above illustrated examples but may variously be changed within the scope of the present invention. For example, illustrated examples in the respective embodiments may be combined. -14-

Explanation of Reference Symbols [0052] 1: Connector 2: Film 10, 17, 18: Ground pattern 11, 13, 15, 16, 40: Ground terminal 12: Protruded ground terminal 14: Bridge pattern 19: Gap 20: Power feeding terminal 30, 32, 33, 35: Antenna element 41: Linear pattern

Claims

CLAIMS1, An antenna device for a vehicle window, characterized by comprising: a ground pattern disposed in substantially parallel to a vehicle body edge portion and having a ground terminal and a loop-shaped portion; a power feeding terminal disposed near the ground pattern; and an antenna element extending in the perpendicular direction with respect to the ground pattern from the power feeding terminal.
2. The antenna device for a vehicle window according to claim 1, in which the ground pattern has, inside the loop-shaped portion, a plurality of bridge patterns arranged in parallel to the antenna element.
3. The antenna device for a vehicle window according to claim 1 or claim 2, in which the ground pattern has at least one gap in the loop-shaped portion.
4. The antenna device for a vehicle window according to any of claims 1 to 3, in which the antenna element has two patterns extending in parallel in the perpendicular direction with respect to the ground pattern from the power feeding terminal.
5. The antenna device for a vehicle window according to claim 4, in which end portions of the two patterns constituting the antenna element are connected to each other.
6. The antenna device for a vehicle window according to any claims 1 to 5, in which the power feeding terminal is disposed near the center of the ground pattern in longitudinal direction thereof.
7. The antenna device for a vehicle window according to any of claims 1 to 6, in which the ground pattern is disposed so as to surround a part of the power feeding terminal with a predetermined interval from the power feeding terminal.
8. The antenna device for a vehicle window according to any of claims 1 to 7, in which the ground pattern further has a linear pattern extending in parallel to the longitudinal direction of the ground pattern from the ground terminal.
9. The antenna device for a vehicle window according to any of claims 1 to 8, in which the loop-shaped portion of the ground pattern is disposed at a location near the end portion of the ground pattern away from the power feeding terminal.