GLASS ANTENNA FOR VEHICLE
BACKGROUND OF THE INVENTION
This invention relates to an antenna, and, in particular, relates to a
glass antenna which is to be mounted on a vehicle window glass and is
suitable for receiving digital terrestrial TV broadcast signals and UHF analog
TV broadcast signals.
For vehicle glass antennas, antennas to be mounted in the spaces
upper or lower than heating conductive lines of defogger on rear window
glasses have been developed and widely known so far (for example, refer to JP
2008-124822 A, JP 2005-354139 A, JP 2008-135944 A, and JP 2007-150966
A). To mount such an antenna on a rear window glass, the space for
mounting the antenna is limited because defogging heating lines are arranged
over most of the area of the rear window glass.
Besides, to improve the antenna sensitivity of a rear window glass
antenna, the number of elements is increased or vertical elements are added
within the defogger area. Accordingly, the antenna pattern has been more
complex, so good looks and the field of view can not be achieved. In addition,
the increase in the number of element lines has caused a problem of increase
in time and costs for tuning development.
If an antenna is mounted on a front window glass to improve its
receiving performance, a simpler antenna pattern and a more compact size are
required for the antenna to ensure a wider field of view through the front
window glass.
All of the antennas in the above-referenced patent documents are
large-sized antennas to be mounted on rear window glasses and are not
compact antennas particularly intended to be mounted on front window
glasses, for which drivers' field of view is considered to be more important.
Accordingly, a more compact and simpler antenna is desired that is to be
mounted on a front window glass and does not interfere with the driver's field
of view.
An object of this invention is to provide an antenna with simple pattern
which ensures required sensitivity and can be arranged on a front window
glass.
SUMMARY OF THE INVENTION
An aspect of this invention is an antenna including a core-side element
(1) connected to a core-side feed point (3) and a ground-side element (2)
connected to a ground-side feed point (4), characterized in that: the core-side
element extends from the core-side feed point in a predetermined direction;
the ground-side element includes: a first element (21) which is connected to
the ground-side feed point and extends in parallel to the core-side element,
and a second element (24) which is connected to the ground-side feed point
and extends in parallel to the first element; and the first element is arranged
close to a body flange (5) to capacitively couple with the body flange.
In another aspect, the core-side element (1) includes at least one line
extending from the core-side feed point in a horizontal direction.
In another aspect, the first element (21) extends in parallel to the
core-side element via a conductive part (22) extending from the ground-side
feed point in a first vertical direction; and the second element (24) extends in
parallel to the first element via a conductive part (25) extending from the
ground-side feed point in a second vertical direction opposite from the first
vertical direction.
In another aspect, the first element and the second element extend in
the direction in which the core-side element extends.
In another aspect, at least one of the first element (21) and the second
element (22) includes an auxiliary element (27, 28) which extends in a
direction opposite from the direction in which the first element and the second
element extend.
In another aspect, a diversity antenna comprises a pair of the above
described antennas placed side by side.
In another aspect, at least a part of the elements, the conductive parts,
and the feed points of the antenna are arranged on a ceramic paste layer (6)
provided on an interior surface of a rim of a window glass; and at least a part of
the elements, the conductive parts, and the feed terminals are masked with a
resin cover.
The antenna of this invention achieves a simpler antenna pattern and
ensures required antenna sensitivity by an arrangement in which one element
line of a ground-side element is arranged close to the body flange while
another element line of the ground-side element is arranged on the opposite
side. Accordingly, a compact and high-performance antenna can be provided
that will not be a disturbance to the driver's field of view even if the antenna is
mounted on the front window glass.
Furthermore, one element line of the ground-side element is arranged
close to the body flange and the other element line of the ground-side element
is arranged on the opposite side, so easy tuning of the antenna characteristics
is achieved and the development period is shortened.
Furthermore, at least a part of antenna elements, conductive parts,
and feed terminals is arranged on ceramic paste, so the antenna is hardly seen
from the outside of the vehicle, providing good looks. Besides, at least a part
of the antenna elements, the conductive parts, and the feed terminals are
covered with the vehicle interior material made of resin, providing good looks
from the inside of the vehicle likewise.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an explanatory diagram illustrating a configuration of a glass
antenna according to a first embodiment of this invention.
FIG. 2 is an explanatory diagram illustrating a configuration of a glass
antenna according to a second embodiment of this invention.
FIG. 3 is an explanatory diagram illustrating a configuration of a glass
antenna according to a third embodiment of this invention.
FIG. 4 is an explanatory diagram illustrating a configuration of a glass
antenna according to a fourth embodiment of this invention.
FIG. 5 is an explanatory diagram illustrating a configuration of a glass
antenna according to a fifth embodiment of this invention.
FIG. 6 is an explanatory diagram illustrating a configuration of a glass
antenna according to a sixth embodiment of this invention.
FIG. 7 is an explanatory diagram illustrating a configuration of a glass
antenna according to a seventh embodiment of this invention.
FIG. 8 is an explanatory diagram illustrating a configuration of a glass
antenna according to an eighth embodiment of this invention.
FIG. 9 is an explanatory diagram illustrating a characteristics of the
glass antenna according to the first embodiment of this invention.
FIG. 10 is an explanatory diagram illustrating a characteristics of the
glass antenna according to the first embodiment of this invention.
FIG. 11 is an explanatory diagram illustrating a configuration of a
glass antenna according to a ninth embodiment of this invention.
FIG. 12 is an explanatory diagram illustrating a modified example in
which the antenna according to the first embodiment of this invention has
been tuned to another frequency.
FIG. 13 is an explanatory diagram illustrating a configuration of a
glass antenna according to a tenth embodiment of this invention.
FIG. 14 is an explanatory diagram illustrating a configuration of a
glass antenna according to an eleventh embodiment of this invention.
FIG. 15 is an explanatory diagram illustrating a configuration of a
glass antenna according to a twelfth embodiment of this invention.
FIG. 16 is an explanatory diagram illustrating a configuration of a
glass antenna according to a thirteenth embodiment of this invention.
FIG. 17 is an explanatory diagram illustrating a configuration of a
glass antenna according to a fourteenth embodiment of this invention.
FIG. 18 is an explanatory diagram illustrating a configuration of a
glass antenna according to a fifteenth embodiment of this invention.
FIG. 19 is an explanatory diagram illustrating the characteristics of the
glass antenna according to the twelfth embodiment of this invention.
FIG. 20 is an explanatory diagram illustrating a configuration of
comparative example of a glass antenna.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Hereinafter, vehicle glass antennas according to preferred
embodiments of this invention will be described.
FIRST EMBODIMENT
FIG. 1 illustrates a configuration of a glass antenna according to a first
embodiment of this invention.
The glass antenna according to the embodiments of this invention
comprises a core-side element 1 and a ground-side element 2. The core-side
element 1 is connected to a feed terminal 3 and the ground-side element 2 is
connected to a feed terminal 4. The feed terminals 3 and 4 are connected to a
receiver (for example, a television set) via feeder cables.
The ground-side element 2 comprises a first element 21 connected to
an upper part of the feed terminal 4 and a second element 24 connected to a
lower part thereof.
The first element 21 extends upward from the right end of the feed
terminal 4 to form a vertical part 22. It should be noted that the vertical part
22 may extend from the left end or the middle of the feed terminal 4 as in the
tenth and eleventh embodiments, which will be described later.
The end of the vertical part 22 bends in the direction of the feed
terminal 3 (leftward) and extends to the proximity of the feed terminal 3 to
form a horizontal part 23. The horizontal part 23 lies close to the body flange
5 of the vehicle on which this antenna is mounted; the first element 21
capacitively couples with the body flange 5 (the ground). In particular, the
horizontal part 23 is arranged in parallel to the body flange, so that the
entirety of the horizontal part 23 capacitively couples with the body flange.
The second element 24 extends downward from the right end of the
feed terminal 4 to form a vertical part 25. It should be noted that the vertical
part 25 may extend from the left end or the middle of the feed terminal 4.
Then, the end of the vertical part 25 bends in the direction of the feed terminal
3 (leftward) and extends to the proximity of the feed terminal 3 to form a
horizontal part 26.
Through such an arrangement of the elements, the first element 21
and the second element 24 are arranged opposite from each other
sandwiching the core-side feed terminal therebetween.
Although the horizontal part 23 of the first element 21 and the
horizontal part 26 of the second element 24 extend in the direction of the feed
terminal 3 (leftward), they may extend in the direction opposite from the feed
terminal 3, wherein the strength of the coupling between the first element 21
and the body flange changes in accordance with the current distribution in the
body flange 5. However, it is preferable that the horizontal part 23 and the
horizontal part 26 extend in the direction of the feed terminal 3 (leftward)
because the antenna can be made compact in size.
As for the antenna according to the first embodiment, the feed
terminals 3 and 4, the core-side element 1, and the ground-side element 2 are
formed by printing and stoving conductive silver paste on a ceramic paste
layer 6 provided on the inner surface of a vehicle window glass. The end of
the ceramic paste layer 6 is denoted by a dashed line. The ceramic paste
layer 6 is usually a black and belt-shaped insulating layer formed by stoving
screen-printed ceramic paste on the glass. The ceramic paste is a paste made
of low-melting glass powder and pigments.
The antenna arranged on the ceramic paste layer in the
above-described manner provides better looks because the antenna and the
feed terminals are covered with the black ceramic paste so that they are
invisible from the outside of the vehicle.
In FIG. 1, a part of the core-wire element 1 and the whole ground-side
element 2 are arranged on the ceramic paste layer 6. However, a part of the
core-wire element 1 and a part of the ground-side element 2 may be arranged
on the ceramic paste layer 6; the whole core-wire element 1 and the whole
ground-side element 2 may be arranged on the ceramic paste layer 6; or the
whole core-wire element 1 and a part of the ground-side element 2 may be
arranged on the ceramic paste layer 6.
It is preferable that the antenna according to the first embodiment
comprise a cover for masking the core-side element 1 and the ground-side
element 2. Preferably, the cover is made of a vehicular interior material,
which is resin, and masks a part or the entirety of the core-side element 1 and
the ground-side element 2. Since the cover makes the feed terminals 3 and 4
and the elements invisible from the inside of the vehicle, the looks from the
inside of the vehicle improves. In particular, the feed terminals 3 and 4 and
the coaxial cables connecting to the feed terminals are noticeable; it is
preferable that at least the feed terminals and the cables be masked with the
cover.
The workings of the glass antenna according to this embodiment will
now be discussed.
The antenna according to this embodiment is an ungrounded antenna
whose ground-side element 2 is not actually grounded. However, the first
element 21 capacitively couples with the body flange. Accordingly, the
electric potential of the first element 21 is close to the ground level. Therefore,
the antenna according to this embodiment may be considered as a monopole
antenna which comprises a ground-side element 2 for the ground and a
core-side element 1 for a radiating element.
In the meanwhile, the second element 24 may be considered to
function as a radiating element. In this case, the ground-side element 2
functions as a radiating element on the ground side, which is opposed to the
core-side element 1. Therefore, the antenna according to this embodiment
may be considered as a dipole antenna.
In view of the aboves, the antenna according to this embodiment may
be considered to have characteristics of a monopole antenna and
characteristics of a dipole antenna together. Therefore, as will be described
later, the antenna characteristics change in different ways depending on
whether the length of the first element 21 is changed or the length of the
second element 24 is changed.
To provide such characteristics to the first element 21 and the second
element 24, it is necessary that the first element 21 be strongly coupled with
the body flange. On the other hand, the second element 24 does not need to
be coupled with the feed terminal 3 or does not need to be coupled so strong,
depending on the length of the second element 24.
The horizontal part 26 of the second element 24 is shorter than the
horizontal part 23 of the first element 21 and is shorter than the core-side
element 1. Therefore, focusing on the function of the ground-side element 2
as a radiating element, the ground-side element 2 (for example, the length of
the horizontal part 26) affects the characteristics (for example, sensitivity) at
high frequencies. For example, as shown in FIG. 10, the characteristics at
low frequencies change little as the length of the horizontal part 26 of the
second element 24 is changed from 30 mm to 50 mm, and further to 70 mm,
but the characteristics at higher frequencies change considerably.
In other words, since the ground-side element 2 is configured to be
separated into a part which is closely coupled with the body flange and a part
which is not coupled with the body flange, the changes in antenna
characteristics differ depending on the structure of the part (the length, the
shape of the element, the number of elements, and the like) so that the
antenna characteristics can be tuned easily.
The antenna according to the first embodiment in FIG. 1 is to be
arranged along the top rim of the vehicle window glass, so the first element 21
is provided in parallel to the body flange. However, the antenna may be
arranged along the bottom rim of the window glass. In such a case, the
second element 24 is arranged in parallel to the body flange to capacitively
couple with the body flange.
It is preferable that the antenna according to this embodiment be
arranged along the upper rim of a vehicle front window glass. However, it
may be arranged along the top rim of a rear window glass or a side window
glass. Moreover, if it receives vertically polarized signals, it may be arranged
along a side rim of a front window glass, a rear window glass or a side window
glass.
Either one or both of the vertical parts 22 and 25 are not necessarily
provided. For example, as will be described later in the seventh and the
eighth embodiments, either one or both of the vertical parts 22 and 25 do not
need to be provided.
FIG. 1 also includes examples of the dimensions when the first
embodiment has been applied to an antenna for the UHF television band in
Japan (470 to 770 MHz). It is preferable that the length of the core-side
element 1 be the value obtained by multiplying 1/4 of the wavelength
corresponding to a frequency (620 MHz) close to the central frequency of the
antenna by the wavelength shortening rate a. The dimensions shown in FIG.
1 are for an example of the glass antenna according to the first embodiment
but are not for limiting this embodiment.
Hereinafter, modified examples of this invention will be described. In
the following modified examples, the constituents same as in the
above-described first embodiment are denoted by the same reference signs
and the descriptions thereon will be omitted.
SECOND EMBODIMENT
FIG. 2 illustrates a configuration of a glass antenna according to a
second embodiment of this invention.
The glass antenna according to the second embodiment is an antenna
with a horizontal part (an auxiliary element) 27 added to the ground-side
element 2 of the above-described glass antenna according to the first
embodiment.
The glass antenna according to the second embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof. A
horizontal part 26 of the second element 24 extends to the proximity of the
feed terminal 3.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Then, the end of the vertical part 22 bends in the direction of
the feed terminal 3 (leftward) and extends to the proximity of the feed terminal
3 to form a horizontal part 23. The first element 21 bifurcates at the end of
the vertical part 22 and extends in the direction opposite from the feed
terminal 3 (rightward) to form the horizontal part 27.
The horizontal part 23 and the horizontal part 27 are close to the body
flange 5 of the vehicle on which this antenna is to be mounted, so the first
element 21 capacitively couples with the body flange 5 (the ground). In
particular, the horizontal part 23 and the horizontal part 27 are arranged in
parallel to the body flange, so that the entirety of the horizontal part 23 and
the horizontal part 27 capacitively couples with the body flange.
Although the horizontal part 27 has a shorter length than the
horizontal part 23 in the antenna shown in FIG. 2, the horizontal part 27 may
have the same length as the horizontal part 23 or a longer length than the
horizontal part 23.
According to the antenna of the second embodiment, the whole length
of the horizontal part including the horizontal part 23 can be changed by
adjusting the length of the horizontal part 27. Accordingly, the strength in
the capacitive coupling between the first element 21 and the body flange can
be changed, so that the resonant frequency of the antenna can be changed
easily.
THIRD EMBODIMENT
FIG. 3 illustrates a configuration of a glass antenna according to a
third embodiment of this invention.
The glass antenna according to the third embodiment is an antenna
with a horizontal part (an auxiliary element) 28 added to the ground-side
element 2 of the above-described glass antenna according to the first
embodiment.
The glass antenna according to the third embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof. The
entirety of a horizontal part 23 of the first element 21 is configured to
capacitively couple with the body flange.
The second element 24 extends downward from the feed terminal 4 to
form a vertical part 25. Then, the end of the vertical part 25 bends in the
direction of the feed terminal 3 (leftward) and extends to the proximity of the
feed terminal 3 to form a horizontal part 26. The second element 24
bifurcates at the end of the vertical part 25 and extends in the direction
opposite from the feed terminal 3 (rightward) to form the horizontal part 28.
Although the horizontal part 28 has a shorter length than the
horizontal part 26 in the antenna shown in FIG. 3, the horizontal part 28 may
have the same length as the horizontal part 26 or a longer length than the
horizontal part 26.
According to the antenna of the third embodiment, the whole length of
the horizontal part including the horizontal part 26 can be changed by
adjusting the length of the horizontal part 28. Accordingly, the antenna
characteristics at high frequencies can be changed easily.
FOURTH EMBODIMENT
FIG. 4 illustrates a configuration of a glass antenna according to a
fourth embodiment of this invention.
The glass antenna according to the fourth embodiment is an antenna
with a horizontal part (an auxiliary element) 27 added to the first element 21
on the ground side of the above-described glass antenna according to the first
embodiment, as well as a horizontal part (an auxiliary element) 28 added to
the second element 24 on the ground side thereof.
The glass antenna according to the fourth embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Then, the end of the vertical part 22 bends in the direction of
the feed terminal 3 (leftward) and extends to the proximity of the feed terminal
3 to form a horizontal part 23. The first element 21 bifurcates at the end of
the vertical part 22 and extends in the direction opposite from the feed
terminal 3 (rightward) to form the horizontal part 27.
The horizontal part 23 and the horizontal part 27 are close to the body
flange 5 of the vehicle on which this antenna is to be mounted, so the first
element 21 capacitively couples with the body flange 5 (the ground). In
particular, the horizontal part 23 and the horizontal part 27 are arranged in
parallel to the body flange, so that the entirety of the horizontal part 23 and
the horizontal part 27 capacitively couples with the body flange.
The second element 24 extends downward from the feed terminal 4 to
form a vertical part 25. Then, the end of the vertical part 25 bends in the
direction of the feed terminal 3 (leftward) and extends to the proximity of the
feed terminal 3 to form a horizontal part 26. The second element 24
bifurcates at the end of the vertical part 25 and extends in the direction
opposite from the feed terminal 3 (rightward) to form the horizontal part 28.
Although the horizontal part 27 has a shorter length than the
horizontal part 23 in the antenna shown in FIG. 4, the horizontal part 27 may
have the same length as the horizontal part 23 or a longer length than the
horizontal part 23. Similarly, although the horizontal part 28 has a shorter
length than the horizontal part 26, the horizontal part 28 may have the same
length as the horizontal part 26 or a longer length than the horizontal part 26.
According to the antenna of the fourth embodiment, the whole length
of the horizontal part of the first element 21 including the horizontal part 23
can be changed by adjusting the length of the horizontal part 27. Accordingly,
the strength in the capacitive coupling between the first element 21 and the
body flange can be changed, so that the resonant frequency of the antenna
can be changed. In addition, the whole length of the horizontal part of the
second element 24 including the horizontal part 26 can be changed by
adjusting the length of the horizontal part 28. Accordingly, the antenna
characteristics at high frequencies can be changed easily.
FIFTH EMBODIMENT
FIG. 5 illustrates a configuration of a glass antenna according to a fifth
embodiment of this invention.
The glass antenna according to the fifth embodiment is an antenna
with a plurality of horizontal parts of the first element of the above-described
glass antenna according to the first embodiment.
The glass antenna according to the fifth embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof. A
horizontal part 26 of the second element 24 extends to the proximity of the
feed terminal 3.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Then, the end of the vertical part 22 bends in the direction of
the feed terminal 3 (leftward) and extends to the proximity of the feed terminal
3 to form a horizontal part 23. The first element 21 bifurcates at the middle
of the vertical part 22 and extends in the direction of the feed terminal 3
(leftward) to form a horizontal part 29, which is parallel to the horizontal part
23.
The horizontal part 23 is close to the body flange 5 of the vehicle on
which this antenna is to be mounted, so the first element 21 capacitively
couples with the body flange 5 (the ground). In particular, the horizontal part
23 is arranged in parallel to the body flange and the horizontal part 29 is
arranged in parallel to the horizontal part 23, so that the entirety of the
horizontal part 23 and the horizontal part 29 capacitively couples with the
body flange. In other words, the horizontal part 29 capacitively couples with
the body flange via the horizontal part 23.
According to the antenna of the fifth embodiment, the strength in the
capacitive coupling between the first element 21 and the body flange can be
changed by adjusting the lengths of the horizontal parts 23 and 29, so that the
resonant frequency of the antenna can be changed.
It should be noted that the horizontal part 23 and/or the horizontal
part 26 may extend rightward applying any one of the second to the fourth
embodiments to the antenna according to the fifth embodiment.
SIXTH EMBODIMENT
FIG. 6 illustrates a configuration of a glass antenna according to a
sixth embodiment of this invention.
In the glass antenna according to the sixth embodiment, the horizontal
part of the first element 21 in the above-described glass antenna according to
the first embodiment is loop-shaped.
The glass antenna according to the sixth embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof. A
horizontal part 26 of the second element 24 extends to the proximity of the
feed terminal 3.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Furthermore, the first element 21 includes a loop conductor
30 at the end of the vertical part 22. The end of the loop conductor 30
extends to the proximity of the feed terminal 3.
The loop conductor 30 is close to the body flange 5 of the vehicle on
which this antenna is to be mounted, so the first element 21 capacitively
couples with the body flange 5 (the ground). In particular, the upper line of
the loop conductor 30 is arranged in parallel to the body flange, so that the
whole upper line of the loop conductor 30 capacitively couples with the body
flange.
Since the antenna according to the sixth embodiment is equipped with
the loop conductor 30 at the end of the first element 21, the band for the
antenna can be broadened, and additionally, the resonant frequency of the
antenna can be changed easily.
It should be noted that, the horizontal part 26 may extend rightward
applying the third embodiment to the antenna according to the sixth
embodiment.
SEVENTH EMBODIMENT
FIG. 7 illustrates a configuration of a glass antenna according to a
seventh embodiment of this invention.
The glass antenna according to the seventh embodiment is an antenna
which does not have the vertical part 25 in the above-described glass antenna
according to the first embodiment.
The glass antenna according to the seventh embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof.
The horizontal part 23 of the first element 21 is connected to the feed
terminal 4 via a vertical part 22. The entirety of the horizontal part 23 is
configured to capacitively couple with the body flange 5. The second element
24 extends in the direction of the feed terminal 3 (leftward) horizontally from
the feed terminal 4 to the proximity of the feed terminal 3 to form a horizontal
part 26.
According to the antenna of the seventh embodiment, like in the
above-described first embodiment, the resonant frequency of the antenna
changes depending on the length of the first element 21 and the sensitivity at
high frequencies changes depending on the length of the second element 24.
Accordingly, the antenna characteristics can be tuned easily.
Although the configuration without a vertical part 25 has been
described as the seventh embodiment, the seventh embodiment includes a
configuration in which the feed terminal 4 is located on the upper side while a
vertical part 25 is provided and the vertical part 22 is not provided.
EIGHTH EMBODIMENT
FIG. 8 illustrates a configuration of a glass antenna according to an
eighth embodiment of this invention.
The glass antenna according to the eighth embodiment is an antenna
which has neither the vertical part 22 nor the vertical part 25 in the
above-described glass antenna according to the first embodiment.
The glass antenna according to the eighth embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of a feed
terminal 4 and a second element 24 connected to a lower part thereof.
The first element 21 extends from the feed terminal 4 in the direction of
the feed terminal 3 (leftward) to form a horizontal part 23. The entirety of the
horizontal part 23 is configured to capacitively couple with the body flange.
The second element 24 extends from the feed terminal 4 to the proximity of the
feed terminal 3 in the direction of the feed terminal 3 (leftward) to form a
horizontal part 26.
According to the antenna of the eighth embodiment, like in the
above-described first embodiment, the resonant frequency of the antenna
changes depending on the length of the first element 21 and the sensitivity at
high frequencies changes depending on the length of the second element 24.
Accordingly the antenna characteristics can be tuned easily.
ANTENNA CHARACTERISTICS
FIG. 9 illustrates the antenna characteristics of the glass antenna
according to the first embodiment of this invention.
FIG. 9 shows changes in antenna sensitivity when the length of the
horizontal part 23 of the first element 21 is changed from 40 mm to 60 mm,
and further to 80 mm. As seen from FIG. 9, the longer the horizontal part 23,
the lower the resonant frequency of the antenna. In this situation, other
characteristics including the sensitivity at higher frequencies show little
change.
The resonant frequency can be changed in the same manner as in the
characteristics graph of FIG. 9 by changing the length of the horizontal part 27
in the second or the fourth embodiment.
FIG. 10 illustrates the antenna characteristics of the glass antenna
according to the first embodiment of this invention.
FIG. 10 shows changes in antenna sensitivity when the length of the
horizontal part 24 of the second element 24 is changed from 30 mm to 50 mm,
and further to 70 mm. As seen from FIG. 10, the longer the horizontal part
26, the lower the sensitivity at high frequencies (particularly, at higher than
570 MHz). In this situation, other characteristics including the sensitivity at
lower frequencies show little change.
The sensitivity at high frequencies can be changed in the same manner
as in the characteristics graph of FIG. 10 by changing the length of the
horizontal part 28 in the third or the fourth embodiment.
NINTH EMBODIMENT
FIG. 11 illustrates a configuration of a glass antenna according to a
ninth embodiment of this invention.
The glass antenna according to the ninth embodiment is a diversity
antenna comprised of two glass antennas according to the first embodiment
arranged line symmetrically in such a manner that the ground-side elements
2 are opposed to each other. The reason why the ground-side elements 2 are
arranged oppositely to each other is that the distance between the core-side
elements 1 on the radiant side is wider to improve the diversity characteristics.
For the diversity antenna according to the ninth embodiment, it is preferable
to place the antennas more than 1/4 of the wavelength away from each other.
Although FIG. 11 illustrates a diversity antenna using the antennas
according to the first embodiment, the diversity antenna may be composed of
the antennas according to any of the second to the fifteenth embodiments.
TENTH EMBODIMENT
FIG. 13 illustrates a configuration of a glass antenna according to a
tenth embodiment of this invention.
In the glass antenna according to the tenth embodiment, the vertical
part 22 of the above-described antenna according to the first embodiment
extends upward from the left end of a feed terminal 4.
The glass antenna according to the tenth embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to an upper part of the feed
terminal 4 and a second element 24 connected to a lower part thereof.
The first element 21 comprises a vertical part 22 and a horizontal part
23. The horizontal part 23 is connected to the feed terminal 4 via a vertical
part 22, which extends upward from the left end of the feed terminal 4, and
extends from the connection point with the vertical part 22 in the direction of
the feed terminal 3 (leftward). The entirety of the first element 21 is
configured to capacitively couple with the body flange.
The second element 24 comprises a vertical part 25 and a horizontal
part 26. The horizontal part 26 is connected to the feed terminal 4 via a
vertical part 25, which extends downward from the right end of the feed
terminal 4, and extends horizontally from the connection point with the
vertical part 25 to the proximity of the feed terminal 3 in the direction of the
feed terminal 3 (leftward).
According to the antenna of the tenth embodiment, like in the
above-described first embodiment, the resonant frequency of the antenna
changes depending on the length of the first element 21 and the sensitivity at
high frequencies changes depending on the length of the second element 24,
so the antenna characteristics can be tuned easily.
ELEVENTH EMBODIMENT
FIG. 14 illustrates a configuration of a glass antenna according to an
eleventh embodiment of this invention.
In the glass antenna according to the eleventh embodiment, the
vertical part 22 of the above-described antenna according to the first
embodiment extends upward from the middle of a feed terminal 4.
The glass antenna according to the eleventh embodiment comprises a
core-side element 1 on the feed side and a ground-side element 2. The
core-side element 1 is connected to a feed terminal 3. The ground-side
element 2 comprises a first element 21 connected to the upper part of the feed
terminal 4 and a second element 24 connected to the lower part thereof.
The first element 21 comprises a vertical part 22 and a horizontal part
23. The horizontal part 23 is connected to the feed terminal 4 via a vertical
part 22, which extends upward from the middle of the top end of the feed
terminal 4, and extends from the connection point with the vertical part 22 in
the direction of the feed terminal 3 (leftward). The entirety of the first element
21 is configured to capacitively couple with the body flange.
The second element 24 comprises a vertical part 25 and a horizontal
part 26. The horizontal part 26 is connected to the feed terminal 4 via a
vertical part 25, which extends downward from the right end of the feed
terminal 4, and extends horizontally from the connection point with the
vertical part 25 to the proximity of the feed terminal 3 in the direction of a feed
terminal 3 (leftward).
According to the antenna of the eleventh embodiment, like in the
above-described first embodiment, the resonant frequency of the antenna
changes depending on the length of the first element 21 and the sensitivity at
high frequencies changes depending on the length of the second element 24,
so the antenna characteristics can be tuned easily.
In the first, the tenth, and the eleventh embodiments, three examples
have been described in which the position where the first element 21 extends
from the feed terminal 4 differs from one another, but the position where the
first element 21 extends from the feed terminal 4 may be anywhere on the top
end of the feed terminal 4 regardless of the descriptions in these
embodiments.
In the tenth and the eleventh embodiments, the variations of the
position where the first element 21 extending upward from the feed terminal 4
extends from the feed terminal 4 have been described. Similarly, the position
where the second element 24 extends downward from the feed terminal 4 may
be anywhere on the bottom end of the feed terminal 4.
Both of the position where the first element 21 extends upward from
the feed terminal 4 and the position where the second element 24 juts out
downward from the feed terminal 4 may be positions other than the right end
of the feed terminal 4. In such a case, the position where the first element 21
extends upward from the feed terminal 4 and the position where the second
element 24 extends downward from the feed terminal 4 may be the same
position (on a single straight line) or different positions.
Furthermore, the position where the first element 21 extends from the
feed terminal 3 may be changed, applying the tenth or the eleventh
embodiment to the above-described antenna according to any one of the
second to the eighth embodiments.
TWELFTH EMBODIMENT
FIG. 15 illustrates a configuration of a glass antenna according to a
twelfth embodiment of this invention.
The glass antenna according to the twelfth embodiment comprises a
sub core-side element 7 which is parallel to the core-side element 1 of the
above-described antenna according to the first embodiment.
The glass antenna according to the twelfth embodiment comprises a
core-side element 1 on the feed side, a sub core-side element 7 on the feed side,
and a ground-side element 2.
The core-side element 1 extends from the middle of the left end of a
feed terminal 3 in the direction away from a feed terminal 4 (leftward). The
sub core-side element 7 comprises a vertical part extending downward from
the left end of the feed terminal 3 and a horizontal part extending in the
direction away from the feed terminal 4 (in other words, leftward in parallel to
the core-side element 1) from the lower end of the vertical part.
The ground-side element 2 comprises a first element 21 connected to
an upper part of the feed terminal 4 and the second element 24 connected to a
lower part thereof.
The first element 21 comprises a vertical part 22 and a horizontal part
23. The horizontal part 23 is connected to the feed terminal 4 via a vertical
part 22, which extends upward from the feed terminal 4, and extends from the
connection point with the vertical part 22 in the direction of the feed terminal
3 (leftward). The entirety of the first element 21 capacitively couples with the
body flange.
The second element 24 comprises a vertical part 25 and a horizontal
part 26. The horizontal part 26 is connected to the feed terminal 4 via a
vertical part 25, which extends downward from the right end of the feed
terminal 4, and extends horizontally from the connection point with the
vertical part 25 to the proximity of the feed terminal 3 in the direction of the
feed terminal 3 (leftward).
It is preferable that the horizontal part 26 of the second element 24 and
the horizontal part of the sub core-side element 7 are located on the same
straight line. The locations of the horizontal part 26 and the horizontal part
of the sub core-side element 7 are not limited to those shown in the drawing
and may be lower (farther than the feed terminals 3 and 4).
According to the antenna of the twelfth embodiment, like in the
above-described first embodiment, the resonant frequency of the antenna
changes depending on the length of the first element 21 and the sensitivity at
high frequencies changes depending on the length of the second element 24,
so the antenna characteristics can be tuned easily. Furthermore, the
element parallel to the core-side element 1 improves the antenna sensitivity
(gain).
The horizontal part 23 and/or the horizontal part 26 may extend
rightward, applying any one of the second to the fourth embodiments to the
antenna according to the twelfth embodiment.
THIRTEENTH EMBODIMENT
FIG. 16 illustrates a configuration of a glass antenna according to a
thirteenth embodiment of this invention.
The glass antenna according to the thirteenth embodiment is an
antenna which includes a plurality of horizontal parts of the first element 21
in the above-described glass antenna according to the twelfth embodiment.
The glass antenna according to the thirteenth embodiment comprises
a core-side element 1 on the feed side, a sub core-side element 7 on the feed
side, and a ground-side element 2.
The core-side element 1 and the sub core-side element 7 are connected
to a feed terminal 3 and they are arranged in parallel. The core-side element
1 extends in the direction away from a feed terminal 4 (leftward) from the
middle of the left end of the feed terminal 3. The sub core-side element 1
comprises a vertical part extending downward from the left end of the feed
terminal 3 and a horizontal part extending in the direction away from the feed
terminal 4 (in other words, leftward in parallel to the core-side element 1) from
the lower end of the vertical part.
The ground-side element 2 comprises a first element 21 connected to
an upper part of the feed terminal 4 and a second element 24 connected to a
lower part thereof.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Then, the end of the vertical part 22 bends in the direction of
the feed terminal 3 (leftward) and extends to the proximity of the feed terminal
3 to form a horizontal part 23. The first element 21 bifurcates at the middle
of the vertical part 22 and extends in the direction of the feed terminal 3
(leftward) to form the horizontal part 29, which is parallel to the horizontal
part 23.
The horizontal part 23 is close to the body flange 5 of the vehicle on
which this antenna is to be mounted, so the first element 21 capacitively
couples with the body flange 5 (the ground). In particular, the horizontal part
23 is arranged in parallel to the body flange and the horizontal part 29 is
arranged in parallel to the horizontal part 23, so that the entirety of the
horizontal part 23 and the horizontal part 29 capacitively couples with the
body flange. In other words, the horizontal part 29 capacitively couples with
the body flange via the vertical part 23.
The second element 24 comprises a vertical part 25 and a horizontal
part 26. The horizontal part 26 is connected to the feed terminal 4 via the
vertical part 25, which extends downward from the feed terminal 4, and
extends horizontally from the connection point with the vertical part 25 to the
proximity of the feed terminal 3 in the direction of the feed terminal 3
(leftward).
It is preferable that the horizontal part 26 of the second element 24 and
the horizontal part of the sub core-side element 7 be on the same straight line.
The locations of the horizontal part 26 and the horizontal part of the sub
core-side element 7 are not limited to those shown in the drawing and may be
lower (farther than the feed terminal 3 and 4).
According to the antenna of the thirteenth embodiment, the additional
element parallel to the core-side element 1 is provided to improve the antenna
sensitivity (gain). Furthermore, the strength of the capacitive coupling
between the first element 21 and the body flange can be changed by adjusting
the lengths of the horizontal parts 23 and 29, so that the resonant frequency
of the antenna can be changed.
The horizontal part 23 and/or the horizontal part 26 may extend
rightward, applying any one of the second to the fourth embodiment to the
antenna according to the thirteenth embodiment.
FOURTEENTH EMBODIMENT
FIG. 17 illustrates a configuration of a glass antenna according to a
fourteenth embodiment of this invention.
In the glass antenna according to the fourteenth embodiment, the
horizontal part of the first element 21 in the above-described glass antenna
according to the twelfth embodiment is loop-shaped.
The glass antenna according to the fourteenth embodiment comprises
a core-side element 1 on the feed side, a sub core-side element 7 on the feed
side, and a ground-side element 2.
The core-side element 1 and the sub core-side element 7 are connected
to a feed terminal 3 and they are arranged in parallel to each other. The
core-side element 1 extends from the middle of the left end of the feed terminal
3 in the direction away from a feed terminal 4 (leftward). The sub core-side
element 7 comprises a vertical part extending downward from the left end of
the feed terminal 3 and a horizontal part extending from the lower end of the
vertical part in the direction away from the feed terminal 4 (in other words,
leftward in parallel to the core-side element 1).
The ground-side element 2 comprises a first element 21 connected to
an upper part of the feed terminal 4 and the second element 24 connected to a
lower part thereof.
The first element 21 extends upward from the feed terminal 4 to form a
vertical part 22. Furthermore, it includes a loop conductor 30 at the end of
the vertical part 22. The end of the loop conductor 30 extends to the
proximity of the feed terminal 3.
The loop conductor 30 is close to the body flange 5 of the vehicle on
which this antenna is to be mounted, so the first element 21 capacitively
couples with the body flange 5 (the ground). In particular, the upper line of
the loop conductor 30 is arranged in parallel to the body flange, so that the
entire upper line of the loop conductor 30 capacitively couples with the body
flange.
The second element 24 comprises a vertical part 25 and a horizontal
part 26. The horizontal part 26 is connected to the feed terminal 4 via the
vertical part 25, which extends downward from the feed terminal 4, and
extends horizontally from the connection point with the vertical part 25 to the
proximity of the feed terminal 3 in the direction of the feed terminal 3
(leftward).
It is preferable that the horizontal part 26 of the second element 24 and
the horizontal part of the sub core-side element 7 be located on the same
straight line. The locations of the horizontal part 26 and the horizontal part
of the sub core-side element 7 are not limited to those shown in the drawing
and may be lower (farther than the feed terminal 3 and 4).
According to the antenna of the fourteenth embodiment, the additional
element parallel to the core-side element 1 is provided to improve the antenna
sensitivity (gain). Besides, since the loop conductor 30 is provided at the end
of the first element 21, a broader band for the antenna can be attained and the
resonant frequency of the antenna can be changed easily.
The horizontal part 26 may extend rightward, applying the third
embodiment to the antenna according to the fourteenth embodiment.
FIFTEENTH EMBODIMENT
FIG. 18 illustrates a configuration of a glass antenna according to a
fifteenth embodiment of this invention.
The glass antenna according to the fifteenth embodiment is an
antenna which includes two vertical parts 22 and 31 in the above-described
antenna according to the twelfth embodiment.
The glass antenna according to the fifteenth embodiment comprises a
core-side element 1 on the feed side, a sub core-side element 7 on the feed side,
and a ground-side element 2.
The core-side element 1 and the sub core-side element 7 are connected
to a feed terminal 3 and they are arranged in parallel to each other. The
core-side element 1 extends from the middle of the left end of the feed terminal
3 in the direction away from a feed terminal 4 (leftward). The sub core-side
element 7 comprises a vertical part extending downward from the left end of
the feed terminal 3 and a horizontal part extending from the lower end of the
vertical part in the direction away from the feed terminal 4 (in other words,
leftward in parallel to the core-side element 1).
The ground-side element 2 comprises a first element 21 connected to
an upper part of the feed terminal 4 and the second element 24 connected to a
lower part thereof.
The first element 21 is comprised of a vertical part 22, a vertical part 31,
and a horizontal part 23. The vertical part 22 extends upward from the right
end of the feed terminal 4 and the vertical part 31 extends upward from the left
end of the feed terminal 4. The horizontal part 23 is connected to the feed
terminal 4 via the vertical parts 22 and 31 and extends from the connection
point with the vertical part 22 in the direction of the feed terminal 3 (leftward),
so that the entirety of the first element 21 capacitively couples with the body
flange.
The top end of the vertical part 31 is connected to the middle of the
horizontal part 23. Namely, in the first element 21, the feed terminal 4, the
vertical part 22, the horizontal part 23, and the vertical part 31 form a loop.
The positions where the vertical parts 22 and 31 extends from the feed
terminal 3 are not limited to those shown in the drawing and may be anywhere
on the top end of the feed terminal 4.
The second element 24 is comprised of a vertical part 25 and a
horizontal part 26. The horizontal part 26 is connected to the feed terminal 4
via the vertical part 25, which extends downward from the right end of the feed
terminal 4, and extends horizontally from the connection point with the
vertical part 25 to the proximity of the feed terminal 3 in the direction of the
feed terminal 3 (leftward).
It is preferable that the horizontal part 26 of the second element 24 and
the horizontal part of the sub core-side element 7 be located on the same
straight line. The locations of the horizontal part 26 and the horizontal part
of the sub core-side element 7 are not limited to those shown in the drawing
and may be lower (farther than the feed terminal 3 and 4).
According to the antenna of the fifteenth embodiment, the additional
element parallel to the core-side element 1 is provided to improve the antenna
sensitivity (gain). Besides, since a loop is formed by the vertical part 22, the
vertical part 31, and the horizontal part 23, a broader band for the antenna
can be attained and the resonant frequency of the antenna can be changed
easily.
The horizontal part 23 and/or the horizontal part 26 may extend
rightward, applying any one of the second to the fourth embodiments to the
antenna according to the fifteenth embodiment.
ANTENNA CHARACTERISTICS
FIG. 19 illustrates the characteristics of the glass antenna according to
the twelfth embodiment of this invention.
FIG. 19 also shows the characteristics of a conventional antenna
shown in FIG. 20 in addition to the characteristics of the glass antenna
according to the twelfth embodiment.
The conventional antenna shown in FIG. 20 comprises a core-side
element 1 on the feed side, a sub core-side element 7 on the feed side, and a
ground-side element 2. The core-side element 1 extends leftward from the
middle of the left end of the feed terminal 3. The sub core-side element 7
extends downward from the left end of the feed terminal 3 and then extends
leftward in parallel to the core-side element 1. The ground-side element 2 is
comprised of a vertical part 25 and a horizontal part 26. The horizontal part
26 is connected to the feed terminal 4 via the vertical part, which extends
downward from the feed terminal 4, and extends horizontally leftward to the
proximity of the feed terminal 3.
Since the antenna according to the embodiments of this invention
comprises the first element 21 located close to the body flange 5 and
capacitively coupling with the ground, the antenna sensitivity (gain) improves
as shown in FIG. 19.
Hereinabove, preferred embodiments of this invention have been
described on antennas for digital territorial broadcast signals in Japan (470 to
710 MHz) and UHF TV broadcast signals by way of example. This invention
may be applied to antennas for other frequency bands, for example, the UHF
digital terrestrial broadcast signals in European countries (470 to 862 MHz) or
the VHF digital terrestrial broadcast signals in European countries (174 to
862 MHz).
FIG. 12 shows a modified example in which the antenna according to
the first embodiment of this invention has been tuned to the 470 to 862 MHz.
Compared with the above-described antenna according to the first
embodiment (FIG. 1), the antenna in FIG. 12 has shorter horizontal elements
(a core-side element 1, a horizontal part 23 of a first element 21, and a
horizontal part 26 of a second element 24) in length by approximately 12%.
This is because the central frequency of the European UHF digital terrestrial
broadcast signals is approximately 12% higher than the central frequency of
Japanese digital terrestrial broadcast signals.
If the central frequency is lower like the North American area, as the
UHF broadcast frequency range is 470 MHz to 698 MHz, it is appropriate that
horizontal elements be longer in accordance with the rate of the central
frequency.
Although the preferred embodiments of this invention have been
described on glass antennas for vehicles, this invention is applicable to any
other types of antennas as far as the antenna is configured with a pattern
formed on an insulating or dielectric material. For example, there is an
antenna provided by bonding a synthetic resin sheet with a pattern thereon to
glass.
Although the antennas according to the above-described preferred
embodiments are horizontally-polarized antennas for receiving television
broadcast signals, they may be rotated clockwise (or counterclockwise) by 90
degrees to provide vertically-polarized antennas for other mobile
communications.
We claim:
1. An antenna including
a core-side element (1) connected to a core-side feed point (3) and
a ground-side element (2) connected to a ground-side feed point (4),
characterized in that:
the core-side element extends from the core-side feed point in a
predetermined direction;
the ground-side element includes,
a first element (21) which is connected to the ground-side feed
point and extends in parallel to the core-side element, and
a second element (24) which is connected to the ground-side
feed point and extends in parallel to the first element; and
the first element is arranged close to a body flange (5) to capacitively
couple with the body flange.
2. The antenna according to claim 1, wherein the core-side element (1)
includes at least one line extending from the core-side feed point in a
horizontal direction.
3. The antenna according to claim 2, wherein:
the first element (21) extends in parallel to the core-side element via a
conductive part (22) extending from the ground-side feed point in a first
vertical direction; and
the second element (24) extends in parallel to the first element via a
conductive part (25) extending from the ground-side feed point in a second
vertical direction opposite from the first vertical direction.
4. The antenna according to claim 1, wherein the first element and the
second element extend in the direction in which the core-side element
extends.
5. The antenna according to claim 1, wherein at least one of the first
element (21) and the second element (22) includes an auxiliary element (27,
28) which extends in a direction opposite from the direction in which the first
element and the second element extend.
6. A diversity antenna comprising a pair of the antennas according to any
one of claims 1 to 5 placed side by side.
7. The antenna according to any one of claims 1 to 5, wherein:
at least a part of the elements, the conductive parts, and the feed
points of the antenna are arranged on a ceramic paste layer (6) provided on an
interior surface of a rim of a window glass; and
at least a part of the elements, the conductive parts, and the feed
terminals are masked with a resin cover.

To provide a sensitive antenna with simple pattern, there is provided
an antenna including a core-side element (1) connected to a core-side feed
point (3) and a ground-side element (2) connected to a ground-side feed point
(4), characterized in that: the core-side element extends from the core-side
feed point in a predetermined direction; the ground-side element includes: a
first element (21) which is connected to the ground-side feed point and
extends in parallel to the core-side element, and a second element (24) which
is connected to the ground-side feed point and extends in parallel to the first
element; and the first element is arranged close to a body flange (5) to
capacitively couple with the body flange.