CA2022953C - Window glass antenna for a motor vehicle - Google Patents
Window glass antenna for a motor vehicleInfo
- Publication number
- CA2022953C CA2022953C CA002022953A CA2022953A CA2022953C CA 2022953 C CA2022953 C CA 2022953C CA 002022953 A CA002022953 A CA 002022953A CA 2022953 A CA2022953 A CA 2022953A CA 2022953 C CA2022953 C CA 2022953C
- Authority
- CA
- Canada
- Prior art keywords
- antenna
- conductor
- heater wires
- window glass
- feed terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000005357 flat glass Substances 0.000 title claims abstract description 17
- 239000004020 conductor Substances 0.000 claims abstract description 86
- 239000011521 glass Substances 0.000 claims abstract description 32
- 238000010438 heat treatment Methods 0.000 claims description 6
- 230000000295 complement effect Effects 0.000 abstract description 4
- 230000008878 coupling Effects 0.000 description 9
- 238000010168 coupling process Methods 0.000 description 9
- 238000005859 coupling reaction Methods 0.000 description 9
- 229910052729 chemical element Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/12—Supports; Mounting means
- H01Q1/1271—Supports; Mounting means for mounting on windscreens
- H01Q1/1278—Supports; Mounting means for mounting on windscreens in association with heating wires or layers
Landscapes
- Details Of Aerials (AREA)
Abstract
A pair of antenna conductors are formed on upper and lower blank portions outside an area where defogging heater wires are attached on a window glass of a motor vehicle.
One of the antenna conductors is RF-coupled with the defogging heater wires and a feed terminal thereof is located at a lateral side of the glass. The other antenna conductor has a feed terminal located at another lateral side of the glass. A pair of reception signals complement with each other in directivity due to asymmetric characteristic of the antenna conductors and are used in a diversity reception system for obtaining a nondirectional reception characteristic.
One of the antenna conductors is RF-coupled with the defogging heater wires and a feed terminal thereof is located at a lateral side of the glass. The other antenna conductor has a feed terminal located at another lateral side of the glass. A pair of reception signals complement with each other in directivity due to asymmetric characteristic of the antenna conductors and are used in a diversity reception system for obtaining a nondirectional reception characteristic.
Description
r~ACI;~I~oc~rrD or ~I~~ IrmErr~x~zorr Field of the Invention ~rhe present invention relates to a glass window antenna for a motor vehicle, wherein antenna conductors are arranged on a surface of a caindow glass used as an insula-tor.
Description of the Prior Art In an antenna system of a motor vehicle, a diver-sity reception using a plurality of antennas is employed for reducing changes in reception gain according to traveling direction of the vehicle. An ~'HI broadcast diversity recep-tion, for example, a pole antenna attached on the body of the motor vehicle and an antenna comprising an antenna conductor attached on a rear glass window are used in a prior art. ~: space diversity reception is so performed that the highest level one in reception signals is selected (cf.
Japanese laid open patent application No.140301/1988).
It is known to perform diversity reception with two or more antenna conductors and feed terminals on a reax window surface of the motor vehicle (Japanese utility model registration application laid open Nos. 13808/1983 and 29307/1988 arid a patent application laid open: No.
269625/1988)) As to the pole antenna, tuning adjustment is possible only with regard to its length. It is less flexible in arrangements of conductor than that of a glass window antenna. ft is therefore difficult to tune conductor =or providing complementary directivity for diversity reception .1 ~ al ".~ ,,'J
l a ~ f,> > ,~ ",,, ;.~
system. An element of the pole antenna is arranged vertical-ly so that it shocus a low reception sensibility to receive horizontally polarized suave.
It is possible to tune directivity of respective antennas in diversity reception system in which, spaced conductors arranged on a surface of a glass window. Spaces on the window, however, are little for the antenna conduc-tOrS SO that they shocu lo~u average reception sensibility.
Preamplifiers ruith fired gains must be inserted immediately after feed terminals of the antenna conductors, nhese fixed gain.amplifiers often saturate at strong radio wave field so that reception radio voice is remarkably degraded.
OBJECT AND SUt~INIARY OF THE INVENTION
Accordingly it is an object of this invention to provide window glass antennas which have good complimentary directivities and high reception sensibilities without using preamplifiers.
In accordance with an aspect of the present inven-tion, there is provided a window glass antenna of a motor vehicle comprising heater cuires formed in a heating area on a window glass of the motor vehicle; a first antenna conduc-tor formed in a lower blank area outside the heating area; a second antenna conductor formed in a lower blank area out-side the heating area and RF-coupled to the heater wires;
and first and second feed terminals arranged oppositely at both lateral sides of the window glass for deriving recep-tion signals from the first and second antenna conductors.
According to opposite wiring courses tacuard the feed terminals, Location of the first and secoFlc'cN~t~ri~i~
conductors is asymmetrical with respect to a center line of glass window. Directivities of the antenna conductors com-element with each other. Non-directional reception charac-teristic is thus achieved by diversity reception) The above, and other, objects, features and advan-tages of the present invention, will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.
BRIEF DESCRIE~TIOrI OF THE DRAVINGS
Fig. 1 is a front view of a rear glass window on which a glass window antenna for a motor vehicle according to this invention is provided;
Fig. 2 is a graph showing directivities of upper and lower antenna conductors;
Fig) 3 is a graph showing variation of reception sensibility with respect to coupling capacity between heater wires and the second antenna conductor;
Fig. 4 is a graph showing a gain of the first antenna conductor for various conductor width of feeder conductor connected thereto;
Fig. s is a graph showing gain of the second antenna conductor in a case in which a hori~,ontal element is added to a bus bar of heater caires and a case in which the horizontal element is not provided;
Fig. 6 is a graph showing gain of antenna in a case in which short-circuit conductor and horizontal ele-ments are added and another case in which these are not g rJ ~~ L,~
provided; and Fig. 7 is a graph showing gain of antenna in a case in cahich horizontal element is provided to capacitively couple to the first antenna conductor and another case in cahich the horizontal element is not provided.
DETAT_Lc,D DESCRIPTIOD1 OF A PREFERRED EL~1BODTP~ZE~'JT
Fig. 1 is shows a rear glass window of a motor vehicle according to this invention. In the middle zone of the glass window, a plurality of defogging heater wires 2 is formed in parallel to each other through a printing and a baking processes. The heater wires 2 are divided into upper and lower groups. Power is fed through bus bars 3 and through a return path via a common bus bar S. Another power feed system may be arranged in cahich heater ~~rires 2 are not divided into two groups so that a current flows from a side bus bar to another side bus bar.
The heater caires 2 are used as an AM radio wave reception antenna. Magnetically coupled choke coils 8a and 8b are inserted iwto power supply lines 7a and '7b. The choke coils provides the heater wires 2 with large impedance to ground in radio frequencies. The power supply line 7a is coupled to a main power supply through a scvitch 6 and the power supply line 7b is caupled to ground.
Antenna conductors 10 and 11 are arranged on upper and lower blank areas of the heater wires 2. The upper antenna conductor 1(? is e:~clusively used for FM .broadcast reception. The lower antenna conductor 11 is used both for AM and Fb~ broadcast receptions. A diversity reception is per-Yd ~~ (J ~ 4s c.I
formed for Fc~9 ;~roadcast reception with using the upper and lower antenna conductors 10 and 11.
Asymmetrical arrangement of conductors is employed faith respect to the center line or the glass window for satisfactory Fr7 diversity reception. For securing asymmetri-cal arrangement of the conductors, a feed terminal 10a of the upper antenna conductor 10 is located at the right side (viewed from inside of a car) of the glass raindow 1 and a feed terminal 11a of the lower antenna conductor 11 is located at left side.
The antenna conductor 10 comprises horizontal ele-ments 10b - 10g. A main element 10b is a single element antenna of about 800 mm in length and is symmetrically arranged with respect to the center line of the glass caindow 1. At the center o= the conductor 10b, a vertical coupling conductor 10h is connected to form an antenna of generally inverse letter -T configuration. The coupling conductor 10h is connected to a feeder conductor 10i arranged along an upper edge of the glass window 1. An end of the feeder conductor 10i is connected to the feed terminal 10a located at the side end of the glass window 1.
The feeder conductor 10i is 3 mm in width and made wider than other conductors so that impedance matching is satisfied between a feeder cable of 5052 to be connected to the feed terminal 10a and the inverse T-antenna comprising the main element 10b and the coupling conductor 10h. The feeder conductor 10i has a desired capacitance to ground which is produced by capacitive coupling to a window frame c~~ra~,~~~~.~~
(ground potential) near the upper edge of the glass cnindow.
A desired impedance measured at the feed terminal 10a is ob-twined.
Horizontal elements 10d and 10f are extended from the bus bar 3 of the heater wires 2 in parallel with the main element 10b. These horizontal elements are capacitively coupled with the main element 10b so as to tune the antenna in directivity. Respective ends of the horizontal elemer_ts 10d and 10f are located at 300 mm and 400 mm away from the center line of the windoca 1.
A short-circuiting conductor 10j of 4 mm in width is provided along the center line of the glass caindow 1 to short-circuit all of upper half of the heater caires 2. A
horizontal element 10g is e:aended from an end of the short-circuit conductor 10j toward the bus bar 3 so as to couple capacitively, with the element 10h for improving directivity. An end of the horizontal element 10g is located at 500 mm away from the center line of the glass window 1.
The short-circuit conductor 10j connects equipotential points of the heater wires 2 so that na short-.circuiting current actually flows through the short-circuit conductor 10j.
Tn.this embodiment, line intervals 10d - 10b, 10b - 10f, 10f - 10g and 10g - heater crires 2 are respectively 10, 15, 7.S and 7,5 mm.
A horizontal auxiliary element 10e of 165 mm in length is extended from the feed terminal 10a so as to tune the antenna in directivit~r as well as high frequency charac---~~l~~r,;~ra~
teristic.
The above-.mentioned elements 10d, 10h, i0g and 10e improve reception directivity of the main element 10b on the left side thereof. These elements are arranged generally on the right side of the center line of the glass caindow 1, The antenna conductor 10 is thus arranged asymmetrically in general with respect to the center line of the glass window 1.
The lower antenna conductor 11 has a horizontal main element 11b extended from the feed terminal 11a in parallel with the heater wires 2 at an interval of 2 mm. The main element 10b is capacitively coupled to the heater wires 2 to serve as an antenna used both in receptions of ADT and ~PZ waves induced on the heater wires 2. The lower half of the heater wires 2 serves as ground circuitry e.g, a return path of a heater current so that noises in a heater power supply do not propagate directly from the heater wires 2 to the main element 11b. No remarkable noises are recognized in a reception signal. An end of the main element 11b is locat-ed at 210 mm away from the center line of the glass window 1.
Auxiliary horizontal elements 11c, 11d and 11e are extended from bus bars 3 and 5 of the heater wires 2 for improving directivity and frequency characteristics of the main element 11b. The heater wires 2 are thus tuned as an antenna. The element 11c is extended horizontally from the locaer end of the common bus bar 5 by 150 mm awav from the center line of the glass window with an interval of 30 mm to ~3 _ mw 4 ~
7., !a ~ ~ ~ ~J ~~ rJ
the heater wires 2.
The element 11d is extended from the lower end of the bus bar 3 along the right side oT the glass window 1 and then extended horizontally to a position X10 mm a~nay from the center line of the glass window 1 with an interval of 15 mm to the heater wires 2.
The element 11e is extended from the upper end of the common bllS bar 5 along a corner portion and upper side of the glass windoc~r 1 to a position 1 SO mm acaay from the center line.
~ig. 2 shows directivity of antenna conductors 10 and 11 with respect to FM broadcast caave of 95 MHz. The directivity of dotted line B11 corresponds to the antenna conductor 10 and the directivity of a solid line D10 corre-sponds to the antenna conductor 11. As is apparent from the directivity chart, a dip in gain of the lower antenna 11 appearing on the right side of a traveling course of a car is complemented by a gain of the upper antenna conductor 10.
In the directivity of the antenna conductor 10, a dip ap-peering on the left side of a traveling course of a car is complemented by a gain of the lower antenna conductor 11. A
diversity reception is achieved by selecting a higher level one of reception signals from the complementary antenna conductors 10 and 11 in response to comparison of these signals. A stable reception signal is obtained regardless of changes of traveling direction of the car.
The lower antenna conductor 11 functions as an t'1b1 reception antenna. In this radio band, the heater wires 2. is _ g _ :~ ~..3 ,.C~ ,,..a r, cl ~,i '" ~.~ G.i -.% r,) 2.~
operable as an ant enna conductor since conductors of the wires are relatively long.
Fig. 3 is a graph showing a relation between AM
reception sensibility and coupling capacitance of the main antenna element 11 to the heater wires 2. Differences in sensibility are plotted with reference to that (OdB) of a rear pole antenna of 1200 mm long. The difference reaches the reference cahen the coupling capacitance exceeds 60 pF, and saturates at 70 pF or more) In the embodiment, the main element 11b and the heater wires 2 are set at an interval of 2 mm to give capacitive coupling not less than 70 pF so that an AM reception signal is obtained by the antenna conductor 11 with a sufficient gain.
Fig. 4 shows reception gains of the upper antenna conductor 10 in FM broadcast wave ranging 80 - 90 MHz in cases cahere width of the feeder conductor 1Oi in Fig. 1 is 1 mm and 8 mm as respectively shown by a dotted line and a solid line. As is apparent from the graph, reception gains in lower side and upper side of FM broadcast band are re-spectively improved when the width of the feeder conductor 10i is set mare than 3 mm. Frequency characteristics are improved over a wide range. The feeder conductar 10i is extended from the center line of the window glass 1 toward right side to the feed terminal 10a and operates as an antenna element which serves to improve reception gain on the right side of traveling course.
Fig. 5 shows reception gains of the lower antenna conductor 11 in a range 80 - 90 MHz in cases where the horizontal elements 11c and 11e are eetended from the common bus 5 of the heater wires 2 and these elements 11c and 11e are removed, respectively as shown by a solid line A and a dotted line B. A condition of FM radio wave current induced on the heater ~oires 2 is changed by extending the elements 11c and 11e from the common bus bar 5 of the heater wires 2, frequencj bands each in which a good sensibility is obtained are shifted to each other as shown by the graph. These elements 11c and 11e are arranged on the left side of the glass window 1 so that it operates to improve reception gain of the lower antenna conductor 11 on the left side of the traveling course.
rFig. 6 shows gain characteristics in a band of 80 - 110 i~9Hz for a case (solid line A) where the short-circuiting conductor 10j is provided to the heater wires 2 in Fig. 1 and the horizontal element 10g is extended from an end of the conductor 10j in parallel to the heater wires 2, and another case (dotted line B) where these conductors 10j and 10g are not used, State of FM radio frequency current induced on the heater wires 2 is changed by attaching these conductors 10j and 10g. Frequency band having good sensibil-ity can be shifted as shown by the graph. The horizontal elements 10g is extended on the left side of the glass caindow 1 so that it operates to improve reception gain of the upper antenna conductor 10 on the left side of the traveling course.
Fig. 7 shows reception gains in a band of 80 - 110 MHz in a ease (solid line A) cahere the horizontal elements 10d and 10f are e:ctended from the bus bar 3 of the heater cvires 2 as shown in Fig. 1 to capacitively couple with the main element 10b on both sides (upper and lower sides) thereof and another case (dotted line B) where the elements 10d and 10f are not used. Influence to the main element 10b by the heater wires 2 can be changed by capacitive coupling of horizontal elements 10d and 10f with the main element 10b at a distance within 15 mm. Frequency band having good sensibility can be shifted as shown by the graph. These horizontal elements 10d and 10f operate to improve a gain of the upper antenna conductor 10 on the right side of a trav-eling course.
According to this invention, due to asymmetrical arrangement of the first and second antenna conductors with respect to the center of the glass window, directivities complementing to each other are obtained. Good reception characteristics are obtained with diversity reception re-gardless of traveling direction of car. especially, a recep-tion system in which any preamplifier is riot employed can be arranged so that a reception signal of high quality is received without distortion even in a strong radio wave field.
According to other features of this invention, reception gains of the first and second antenna conductors are improved. Complementary characteristics of the first and second antenna elements are ensured to operate a diversity reception system with high performance.
Description of the Prior Art In an antenna system of a motor vehicle, a diver-sity reception using a plurality of antennas is employed for reducing changes in reception gain according to traveling direction of the vehicle. An ~'HI broadcast diversity recep-tion, for example, a pole antenna attached on the body of the motor vehicle and an antenna comprising an antenna conductor attached on a rear glass window are used in a prior art. ~: space diversity reception is so performed that the highest level one in reception signals is selected (cf.
Japanese laid open patent application No.140301/1988).
It is known to perform diversity reception with two or more antenna conductors and feed terminals on a reax window surface of the motor vehicle (Japanese utility model registration application laid open Nos. 13808/1983 and 29307/1988 arid a patent application laid open: No.
269625/1988)) As to the pole antenna, tuning adjustment is possible only with regard to its length. It is less flexible in arrangements of conductor than that of a glass window antenna. ft is therefore difficult to tune conductor =or providing complementary directivity for diversity reception .1 ~ al ".~ ,,'J
l a ~ f,> > ,~ ",,, ;.~
system. An element of the pole antenna is arranged vertical-ly so that it shocus a low reception sensibility to receive horizontally polarized suave.
It is possible to tune directivity of respective antennas in diversity reception system in which, spaced conductors arranged on a surface of a glass window. Spaces on the window, however, are little for the antenna conduc-tOrS SO that they shocu lo~u average reception sensibility.
Preamplifiers ruith fired gains must be inserted immediately after feed terminals of the antenna conductors, nhese fixed gain.amplifiers often saturate at strong radio wave field so that reception radio voice is remarkably degraded.
OBJECT AND SUt~INIARY OF THE INVENTION
Accordingly it is an object of this invention to provide window glass antennas which have good complimentary directivities and high reception sensibilities without using preamplifiers.
In accordance with an aspect of the present inven-tion, there is provided a window glass antenna of a motor vehicle comprising heater cuires formed in a heating area on a window glass of the motor vehicle; a first antenna conduc-tor formed in a lower blank area outside the heating area; a second antenna conductor formed in a lower blank area out-side the heating area and RF-coupled to the heater wires;
and first and second feed terminals arranged oppositely at both lateral sides of the window glass for deriving recep-tion signals from the first and second antenna conductors.
According to opposite wiring courses tacuard the feed terminals, Location of the first and secoFlc'cN~t~ri~i~
conductors is asymmetrical with respect to a center line of glass window. Directivities of the antenna conductors com-element with each other. Non-directional reception charac-teristic is thus achieved by diversity reception) The above, and other, objects, features and advan-tages of the present invention, will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.
BRIEF DESCRIE~TIOrI OF THE DRAVINGS
Fig. 1 is a front view of a rear glass window on which a glass window antenna for a motor vehicle according to this invention is provided;
Fig. 2 is a graph showing directivities of upper and lower antenna conductors;
Fig) 3 is a graph showing variation of reception sensibility with respect to coupling capacity between heater wires and the second antenna conductor;
Fig. 4 is a graph showing a gain of the first antenna conductor for various conductor width of feeder conductor connected thereto;
Fig. s is a graph showing gain of the second antenna conductor in a case in which a hori~,ontal element is added to a bus bar of heater caires and a case in which the horizontal element is not provided;
Fig. 6 is a graph showing gain of antenna in a case in which short-circuit conductor and horizontal ele-ments are added and another case in which these are not g rJ ~~ L,~
provided; and Fig. 7 is a graph showing gain of antenna in a case in cahich horizontal element is provided to capacitively couple to the first antenna conductor and another case in cahich the horizontal element is not provided.
DETAT_Lc,D DESCRIPTIOD1 OF A PREFERRED EL~1BODTP~ZE~'JT
Fig. 1 is shows a rear glass window of a motor vehicle according to this invention. In the middle zone of the glass window, a plurality of defogging heater wires 2 is formed in parallel to each other through a printing and a baking processes. The heater wires 2 are divided into upper and lower groups. Power is fed through bus bars 3 and through a return path via a common bus bar S. Another power feed system may be arranged in cahich heater ~~rires 2 are not divided into two groups so that a current flows from a side bus bar to another side bus bar.
The heater caires 2 are used as an AM radio wave reception antenna. Magnetically coupled choke coils 8a and 8b are inserted iwto power supply lines 7a and '7b. The choke coils provides the heater wires 2 with large impedance to ground in radio frequencies. The power supply line 7a is coupled to a main power supply through a scvitch 6 and the power supply line 7b is caupled to ground.
Antenna conductors 10 and 11 are arranged on upper and lower blank areas of the heater wires 2. The upper antenna conductor 1(? is e:~clusively used for FM .broadcast reception. The lower antenna conductor 11 is used both for AM and Fb~ broadcast receptions. A diversity reception is per-Yd ~~ (J ~ 4s c.I
formed for Fc~9 ;~roadcast reception with using the upper and lower antenna conductors 10 and 11.
Asymmetrical arrangement of conductors is employed faith respect to the center line or the glass window for satisfactory Fr7 diversity reception. For securing asymmetri-cal arrangement of the conductors, a feed terminal 10a of the upper antenna conductor 10 is located at the right side (viewed from inside of a car) of the glass raindow 1 and a feed terminal 11a of the lower antenna conductor 11 is located at left side.
The antenna conductor 10 comprises horizontal ele-ments 10b - 10g. A main element 10b is a single element antenna of about 800 mm in length and is symmetrically arranged with respect to the center line of the glass caindow 1. At the center o= the conductor 10b, a vertical coupling conductor 10h is connected to form an antenna of generally inverse letter -T configuration. The coupling conductor 10h is connected to a feeder conductor 10i arranged along an upper edge of the glass window 1. An end of the feeder conductor 10i is connected to the feed terminal 10a located at the side end of the glass window 1.
The feeder conductor 10i is 3 mm in width and made wider than other conductors so that impedance matching is satisfied between a feeder cable of 5052 to be connected to the feed terminal 10a and the inverse T-antenna comprising the main element 10b and the coupling conductor 10h. The feeder conductor 10i has a desired capacitance to ground which is produced by capacitive coupling to a window frame c~~ra~,~~~~.~~
(ground potential) near the upper edge of the glass cnindow.
A desired impedance measured at the feed terminal 10a is ob-twined.
Horizontal elements 10d and 10f are extended from the bus bar 3 of the heater wires 2 in parallel with the main element 10b. These horizontal elements are capacitively coupled with the main element 10b so as to tune the antenna in directivity. Respective ends of the horizontal elemer_ts 10d and 10f are located at 300 mm and 400 mm away from the center line of the windoca 1.
A short-circuiting conductor 10j of 4 mm in width is provided along the center line of the glass caindow 1 to short-circuit all of upper half of the heater caires 2. A
horizontal element 10g is e:aended from an end of the short-circuit conductor 10j toward the bus bar 3 so as to couple capacitively, with the element 10h for improving directivity. An end of the horizontal element 10g is located at 500 mm away from the center line of the glass window 1.
The short-circuit conductor 10j connects equipotential points of the heater wires 2 so that na short-.circuiting current actually flows through the short-circuit conductor 10j.
Tn.this embodiment, line intervals 10d - 10b, 10b - 10f, 10f - 10g and 10g - heater crires 2 are respectively 10, 15, 7.S and 7,5 mm.
A horizontal auxiliary element 10e of 165 mm in length is extended from the feed terminal 10a so as to tune the antenna in directivit~r as well as high frequency charac---~~l~~r,;~ra~
teristic.
The above-.mentioned elements 10d, 10h, i0g and 10e improve reception directivity of the main element 10b on the left side thereof. These elements are arranged generally on the right side of the center line of the glass caindow 1, The antenna conductor 10 is thus arranged asymmetrically in general with respect to the center line of the glass window 1.
The lower antenna conductor 11 has a horizontal main element 11b extended from the feed terminal 11a in parallel with the heater wires 2 at an interval of 2 mm. The main element 10b is capacitively coupled to the heater wires 2 to serve as an antenna used both in receptions of ADT and ~PZ waves induced on the heater wires 2. The lower half of the heater wires 2 serves as ground circuitry e.g, a return path of a heater current so that noises in a heater power supply do not propagate directly from the heater wires 2 to the main element 11b. No remarkable noises are recognized in a reception signal. An end of the main element 11b is locat-ed at 210 mm away from the center line of the glass window 1.
Auxiliary horizontal elements 11c, 11d and 11e are extended from bus bars 3 and 5 of the heater wires 2 for improving directivity and frequency characteristics of the main element 11b. The heater wires 2 are thus tuned as an antenna. The element 11c is extended horizontally from the locaer end of the common bus bar 5 by 150 mm awav from the center line of the glass window with an interval of 30 mm to ~3 _ mw 4 ~
7., !a ~ ~ ~ ~J ~~ rJ
the heater wires 2.
The element 11d is extended from the lower end of the bus bar 3 along the right side oT the glass window 1 and then extended horizontally to a position X10 mm a~nay from the center line of the glass window 1 with an interval of 15 mm to the heater wires 2.
The element 11e is extended from the upper end of the common bllS bar 5 along a corner portion and upper side of the glass windoc~r 1 to a position 1 SO mm acaay from the center line.
~ig. 2 shows directivity of antenna conductors 10 and 11 with respect to FM broadcast caave of 95 MHz. The directivity of dotted line B11 corresponds to the antenna conductor 10 and the directivity of a solid line D10 corre-sponds to the antenna conductor 11. As is apparent from the directivity chart, a dip in gain of the lower antenna 11 appearing on the right side of a traveling course of a car is complemented by a gain of the upper antenna conductor 10.
In the directivity of the antenna conductor 10, a dip ap-peering on the left side of a traveling course of a car is complemented by a gain of the lower antenna conductor 11. A
diversity reception is achieved by selecting a higher level one of reception signals from the complementary antenna conductors 10 and 11 in response to comparison of these signals. A stable reception signal is obtained regardless of changes of traveling direction of the car.
The lower antenna conductor 11 functions as an t'1b1 reception antenna. In this radio band, the heater wires 2. is _ g _ :~ ~..3 ,.C~ ,,..a r, cl ~,i '" ~.~ G.i -.% r,) 2.~
operable as an ant enna conductor since conductors of the wires are relatively long.
Fig. 3 is a graph showing a relation between AM
reception sensibility and coupling capacitance of the main antenna element 11 to the heater wires 2. Differences in sensibility are plotted with reference to that (OdB) of a rear pole antenna of 1200 mm long. The difference reaches the reference cahen the coupling capacitance exceeds 60 pF, and saturates at 70 pF or more) In the embodiment, the main element 11b and the heater wires 2 are set at an interval of 2 mm to give capacitive coupling not less than 70 pF so that an AM reception signal is obtained by the antenna conductor 11 with a sufficient gain.
Fig. 4 shows reception gains of the upper antenna conductor 10 in FM broadcast wave ranging 80 - 90 MHz in cases cahere width of the feeder conductor 1Oi in Fig. 1 is 1 mm and 8 mm as respectively shown by a dotted line and a solid line. As is apparent from the graph, reception gains in lower side and upper side of FM broadcast band are re-spectively improved when the width of the feeder conductor 10i is set mare than 3 mm. Frequency characteristics are improved over a wide range. The feeder conductar 10i is extended from the center line of the window glass 1 toward right side to the feed terminal 10a and operates as an antenna element which serves to improve reception gain on the right side of traveling course.
Fig. 5 shows reception gains of the lower antenna conductor 11 in a range 80 - 90 MHz in cases where the horizontal elements 11c and 11e are eetended from the common bus 5 of the heater wires 2 and these elements 11c and 11e are removed, respectively as shown by a solid line A and a dotted line B. A condition of FM radio wave current induced on the heater ~oires 2 is changed by extending the elements 11c and 11e from the common bus bar 5 of the heater wires 2, frequencj bands each in which a good sensibility is obtained are shifted to each other as shown by the graph. These elements 11c and 11e are arranged on the left side of the glass window 1 so that it operates to improve reception gain of the lower antenna conductor 11 on the left side of the traveling course.
rFig. 6 shows gain characteristics in a band of 80 - 110 i~9Hz for a case (solid line A) where the short-circuiting conductor 10j is provided to the heater wires 2 in Fig. 1 and the horizontal element 10g is extended from an end of the conductor 10j in parallel to the heater wires 2, and another case (dotted line B) where these conductors 10j and 10g are not used, State of FM radio frequency current induced on the heater wires 2 is changed by attaching these conductors 10j and 10g. Frequency band having good sensibil-ity can be shifted as shown by the graph. The horizontal elements 10g is extended on the left side of the glass caindow 1 so that it operates to improve reception gain of the upper antenna conductor 10 on the left side of the traveling course.
Fig. 7 shows reception gains in a band of 80 - 110 MHz in a ease (solid line A) cahere the horizontal elements 10d and 10f are e:ctended from the bus bar 3 of the heater cvires 2 as shown in Fig. 1 to capacitively couple with the main element 10b on both sides (upper and lower sides) thereof and another case (dotted line B) where the elements 10d and 10f are not used. Influence to the main element 10b by the heater wires 2 can be changed by capacitive coupling of horizontal elements 10d and 10f with the main element 10b at a distance within 15 mm. Frequency band having good sensibility can be shifted as shown by the graph. These horizontal elements 10d and 10f operate to improve a gain of the upper antenna conductor 10 on the right side of a trav-eling course.
According to this invention, due to asymmetrical arrangement of the first and second antenna conductors with respect to the center of the glass window, directivities complementing to each other are obtained. Good reception characteristics are obtained with diversity reception re-gardless of traveling direction of car. especially, a recep-tion system in which any preamplifier is riot employed can be arranged so that a reception signal of high quality is received without distortion even in a strong radio wave field.
According to other features of this invention, reception gains of the first and second antenna conductors are improved. Complementary characteristics of the first and second antenna elements are ensured to operate a diversity reception system with high performance.
Claims (7)
1. A window glass antenna of a motor vehicle comprising: ~
heater wires formed in a heating area on a window glass of the motor vehicle;
a first antenna conductor comprising a single horizontal element and a vertical element forming an inverse T shape in an upper blank area outside of the heating area;
a second antenna conductor formed in a lower blank area outside of the heating area and RF-coupled to said heater wires;
first and second feed terminals arranged oppositely at both lateral sides of the window glass for deriving reception signals from said first and second antenna conductors; and means for impedance matching between said first antenna conductor and said first feed terminal including a feeder line of about 3 mm in width connecting a central feed point of said first antenna conductor along an upper edge of said window glass with said first feed terminal.
heater wires formed in a heating area on a window glass of the motor vehicle;
a first antenna conductor comprising a single horizontal element and a vertical element forming an inverse T shape in an upper blank area outside of the heating area;
a second antenna conductor formed in a lower blank area outside of the heating area and RF-coupled to said heater wires;
first and second feed terminals arranged oppositely at both lateral sides of the window glass for deriving reception signals from said first and second antenna conductors; and means for impedance matching between said first antenna conductor and said first feed terminal including a feeder line of about 3 mm in width connecting a central feed point of said first antenna conductor along an upper edge of said window glass with said first feed terminal.
2. A window glass antenna according to claim 1, wherein a line conductor coupled capacitively to said first antenna conductor is extended from a bus bar of the heater wires on the side where said first feed terminal is arranged.
3. A window glass antenna according to claim 2, wherein said line conductor consists of two elements arranged along upper and lower sides of the first antenna conductor.
4. A window glass antenna according to claim 1, further comprising:
a short-circuit conductor which shorts the heater wires at the center thereof;
and a line element extending toward said first feed terminal from an end of the short-circuit conductor in parallel with said first antenna conductor.
a short-circuit conductor which shorts the heater wires at the center thereof;
and a line element extending toward said first feed terminal from an end of the short-circuit conductor in parallel with said first antenna conductor.
5. A window glass antenna according to claim 4, wherein said heater wires are divided into upper and lower groups, said short-circuit conductor being provided along the center line of the glass window to short respective centers of said upper group of heater wires.
6. A window glass antenna according to claim 1, wherein auxiliary horizontal elements are extended from the bus bar of the heater wires on the side of the second feed terminal in the upper and lower blank areas of the glass window to improve antenna characteristic of the heater wires.
7. A window glass antenna according to claim 6, wherein an auxiliary horizontal element is extended from the bus bar of the heater wires on the side of the first feed terminal in the lower blank area.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP202008/1989 | 1989-08-03 | ||
| JP1202008A JP2515158B2 (en) | 1989-08-03 | 1989-08-03 | Car window glass antenna |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2022953A1 CA2022953A1 (en) | 1991-02-04 |
| CA2022953C true CA2022953C (en) | 1999-09-21 |
Family
ID=16450396
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002022953A Expired - Fee Related CA2022953C (en) | 1989-08-03 | 1990-07-31 | Window glass antenna for a motor vehicle |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0411963B1 (en) |
| JP (1) | JP2515158B2 (en) |
| AU (1) | AU636157B2 (en) |
| CA (1) | CA2022953C (en) |
| DE (1) | DE69020256T2 (en) |
| ES (1) | ES2073534T3 (en) |
| ZA (1) | ZA905864B (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0588514B1 (en) * | 1992-09-15 | 1998-09-23 | Ford Motor Company | Hybrid monopole/log-periodic antenna |
| JPH06177625A (en) * | 1992-10-06 | 1994-06-24 | Central Glass Co Ltd | Automotive glass antenna |
| DE4323239C2 (en) * | 1993-07-12 | 1998-04-09 | Fuba Automotive Gmbh | Antenna structure for a motor vehicle rear window |
| JP3458975B2 (en) * | 1993-12-28 | 2003-10-20 | マツダ株式会社 | Glass antenna for vehicle and setting method thereof |
| JP3460217B2 (en) * | 1996-06-20 | 2003-10-27 | マツダ株式会社 | Glass antenna for vehicle and setting method thereof |
| DE10359223A1 (en) | 2003-12-17 | 2005-07-21 | Robert Bosch Gmbh | Vehicle window antenna |
| JP4324037B2 (en) | 2004-07-02 | 2009-09-02 | トヨタ自動車株式会社 | Interior material structure for vehicles |
| DE102007057714A1 (en) * | 2007-11-30 | 2009-06-04 | Robert Bosch Gmbh | Antenna arrangement and method |
| JP5446536B2 (en) * | 2008-09-12 | 2014-03-19 | セントラル硝子株式会社 | Glass antenna |
| JP6459650B2 (en) | 2015-03-09 | 2019-01-30 | セントラル硝子株式会社 | Glass antenna for automobile |
| GB201608383D0 (en) | 2016-05-12 | 2016-06-29 | Pilkington Group Ltd | Connector for antennas, a glazing comprising the connector and an antenna system comprising the connector |
| JP7677048B2 (en) * | 2021-08-04 | 2025-05-15 | Ａｇｃ株式会社 | Vehicle window glass |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS52147622A (en) * | 1976-06-03 | 1977-12-08 | Toyota Motor Co Ltd | Window glass having defogger hot wire for vehicles |
| CA1118621A (en) * | 1979-11-01 | 1982-02-23 | Lawrence C. Smyth | Method and jig for making optical fiber couplers |
| JPS57188102A (en) * | 1981-05-15 | 1982-11-19 | Asahi Glass Co Ltd | Glass antenna for automobile |
| JPS6033525B2 (en) * | 1981-10-12 | 1985-08-03 | 株式会社クボタ | Separation device |
| JPS6329307U (en) * | 1986-08-06 | 1988-02-26 | ||
| JPS63138408U (en) * | 1987-03-03 | 1988-09-12 | ||
| JP2563927B2 (en) * | 1987-04-27 | 1996-12-18 | マツダ株式会社 | Car antenna device |
| JPH0277910U (en) * | 1988-08-24 | 1990-06-14 | ||
| JPH066582Y2 (en) * | 1988-03-31 | 1994-02-16 | 日本板硝子株式会社 | Car window glass antenna |
-
1989
- 1989-08-03 JP JP1202008A patent/JP2515158B2/en not_active Expired - Fee Related
-
1990
- 1990-07-24 AU AU59769/90A patent/AU636157B2/en not_active Ceased
- 1990-07-25 ZA ZA905864A patent/ZA905864B/en unknown
- 1990-07-31 CA CA002022953A patent/CA2022953C/en not_active Expired - Fee Related
- 1990-08-03 ES ES90308579T patent/ES2073534T3/en not_active Expired - Lifetime
- 1990-08-03 DE DE69020256T patent/DE69020256T2/en not_active Expired - Fee Related
- 1990-08-03 EP EP90308579A patent/EP0411963B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| AU636157B2 (en) | 1993-04-22 |
| JPH0365803A (en) | 1991-03-20 |
| DE69020256D1 (en) | 1995-07-27 |
| ES2073534T3 (en) | 1995-08-16 |
| ZA905864B (en) | 1991-05-29 |
| DE69020256T2 (en) | 1996-02-08 |
| JP2515158B2 (en) | 1996-07-10 |
| EP0411963B1 (en) | 1995-06-21 |
| EP0411963A3 (en) | 1991-05-08 |
| CA2022953A1 (en) | 1991-02-04 |
| EP0411963A2 (en) | 1991-02-06 |
| AU5976990A (en) | 1991-02-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |