U.S. patent number RE33,743 [Application Number 07/254,260] was granted by the patent office on 1991-11-12 for on-glass antenna.
Invention is credited to Herbert R. Blaese.
United States Patent |
RE33,743 |
Blaese |
November 12, 1991 |
On-glass antenna
Abstract
An antenna is disclosed which is particularly suitable for use
with a cellular mobile phone. The antenna may be mounted on the
rear window of a vehicle, and it includes a current fed one-quarter
wavelength radiator adapted for mounting on one side of the window.
An electrically conductive inner transfer member is mounted on the
inside of the window in alignment with the radiator and a pair of
spaced field-cancelling conductors are attached to the inside of
the window and are spaced from the inner transfer member. The
central conductor of an RF coaxial cable is coupled to the inner
transfer member and the surrounding ground conductor of the coaxial
cable is coupled to the field-cancelling conductors. In one
embodiment, the one-quarter wavelength radiator comprises a pair of
parallel, spaced radiator elements. RF energy is transferred
through the vehicle window and the drilling of a hole for coupling
the radiator to the coaxial cable is unnecessary.
Inventors: |
Blaese; Herbert R. (Chicago,
IL) |
Family
ID: |
26943938 |
Appl.
No.: |
07/254,260 |
Filed: |
October 6, 1988 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
708667 |
Mar 6, 1985 |
04658259 |
Apr 14, 1987 |
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Current U.S.
Class: |
343/715; 343/713;
343/826; 343/830 |
Current CPC
Class: |
H01Q
1/1285 (20130101) |
Current International
Class: |
H01Q
1/12 (20060101); H01Q 001/32 () |
Field of
Search: |
;343/711,713,715,825,826,829,830,850,900,906 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0137391 |
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Apr 1985 |
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EP |
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541870 |
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May 1956 |
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JP |
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53-109333 |
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Aug 1978 |
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JP |
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744119 |
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Feb 1956 |
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GB |
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Other References
Radio Shack Dictionary of Electronics, Fifth Edition, 1978, edited
by Rudolf F. Graf, pp. 318-319. .
Japanese publication-JP-Y2-57-26406-Jun. 1979, Antenna for
Automobile. .
Japanese publication-JP-Y2-32-13040-Oct. 19, 1957, Antenna
Connector. .
"VHF-UHF Ground Plane Kit" Sheet-1 page (1973). .
Antenna Specialists Catalog Sheet (1979). .
ARRL Antenna Book, pp. 59-60 (1980). .
ARRL Radio Amateurs Handbook, pp. 369-370 (1969). .
Kennedy, "Electronic Communication Systems" Second Edition, pp.
297-301 (1981). .
Rudge, et al., "The Handbook of Antenna Design", pp. 1506-1509,
1512, 1513 (1982, 1983, 1986)..
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Primary Examiner: Wimer; Michael C.
Attorney, Agent or Firm: Gerstman & Ellis Ltd.
Claims
What is claimed is:
1. In an antenna for mounting on a motor vehicle's glass plate with
a radiator extending from a first side of the glass plate and with
an RF coaxial cable extending from the opposite, second side of the
glass plate whereby RF energy is transferred through the glass
plate and the drilling of a hole for connecting the radiator to the
electrical connector is unnecessary, the improvement comprising, in
combination:
a current fed one-quarter wavelength radiator extending in a first
direction and connected to an electrically conductive outer RF
transfer member, said outer transfer member being adapted for
affixation to said first side of the glass plate;
said outer transfer member comprising a weather-resistant carrier
having an electrically conductive member on its underside for
affixation to said first side of the glass plate;
an electrically conductive inner RF transfer member adapted for
affixation to said second side of the glass plate in alignment with
said other transfer member;
said inner transfer member comprising an electrically conductive
tape member for affixation to said second side of the glass
plate;
a pair of electrically conductive field-cancelling tape members
adapted for location on said second side of the glass plate in a
spaced relation to and on opposed sides of said inner tape member
and extending in a direction that is significantly different from
said first direction;
an electrical connector having a main electrical contact and a pair
of ground contacts and being adapted for affixation adjacent said
other side of the glass plate with said main electrical contact in
engagement with said inner transfer member and with one of said
pair of electrical contacts being in engagement with one of said
field-cancelling tape members and the other of said pair of
electrical contacts being adapted for engaging the other of said
field-cancelling tape members;
said RF coaxial cable having a central conductor and a surrounding
ground conductor;
said electrical connector also including means for coupling said
central conductor to said main contact and means for coupling said
ground conductor to said ground contacts.
2. In an antenna as described in claim 1, wherein said one-quarter
radiator comprises a pair of spaced elements which are generally
parallel to each other and are adapted for extension at an angle of
about 45.degree. with respect to the glass plate.
3. In an antenna for mounting on a monitor vehicle's glass plate
with a radiator extending from a first side of the glass plate and
with an electrical connector and electrical wiring extending from
the opposite, second side of the glass plate whereby energy is
transferred through the glass plate and the drilling of a hole for
connecting the radiator to the electrical connector is unnecessary,
the improvement comprising, in combination:
a current fed radiator extending in a first direction and connected
to an electrically conductive outer RF transfer member, said outer
transfer member being adapted for affixation to said first side of
the glass plate;
an electrically conductive RF inner transfer member adapted for
affixation to said second side of the glass plate in alignment with
said outer transfer member;
an electrical connector having a main electrical contact and a
ground contact and being adapted for affixation adjacent said
second side of the glass plate with said main electrical contact in
engagement with said inner transfer member without the need for a
resonant circuit interposed between the electrical wiring and the
inner transfer member;
an electrically conductive field-cancelling member adapted for
location on said second side of the glass plate adjacent to but in
electrically spaced relation to said inner transfer member and
extending in a direction that is significantly different from said
first direction;
said field-cancelling member having a first non-volume containing
portion thereof on one side of the inner transfer member and a
non-volume containing and substantially balanced second portion on
the other side of the inner transfer member; said field-cancelling
member being operative to cancel the electromagnetic field in the
plane of the field-cancelling member;
said ground contact of said electrical connector being adapted for
engagement with said field-cancelling member; and
said electrical connector also including means for coupling said
electrical wiring to said main contact and to said ground
contact.
4. In an antenna as described in claim 3, wherein said current fed
radiator comprises a one-quarter wavelength radiator.
5. In an antenna as described in claim 4, wherein said one-quarter
wavelength radiator comprises a pair of spaced radiator
elements.
6. In an antenna as described in claim 5, wherein said spaced
elements are generally parallel to each other and adapted for
extension at an angle of about 45.degree. with respect to the glass
plate.
7. In an antenna as described in claim 3, said outer transfer
member comprising a weather-resistant carrier having an
electrically conductive member on its underside for affixation to
said first side of the glass plate.
8. In an antenna as described in claim 3, said inner transfer
member comprising an electrically conductive tape member for
affixation to said second side of the glass plate.
9. In an antenna as described in claim 3, said field cancelling
member comprising a pair of electrically conductive tape members
for affixation to said other side of the glass plate in
electrically spaced relation to and on opposed sides of said inner
transfer member.
10. In an antenna as described in claim 9, said ground contact
comprising a pair of electrical contact elements with one of said
pair being adapted for engaging one of said field-cancelling tape
members and the other of said pair being adapted for engaging the
other of said field-cancelling tape members.
11. In an antenna as described in claim 3, said electrical wiring
comprising an RF coaxial cable having a central conductor and a
surrounding ground conductor, said coupling means comprising means
for coupling said central conductor to said main contact and means
for coupling said ground conductor to said ground contact.
12. In an antenna as described in claim 3, said field-cancelling
member comprising a pair of electrically conductive members carried
by said electrical connector.
13. In an antenna as described in claim 3, in which said
field-cancelling member is affixed to said second side of the glass
plate. .Iadd.
14. In an antenna for mounting on a motor vehicle's glass plate
with a radiator extending from a first side of the glass plate and
with an electrical connector and electrical wiring extending from
the opposite, second side of the glass plate whereby energy is
transferred through the glass plate and the drilling of a hole for
connecting the radiator to the electrical connector is unnecessary,
the improvement comprising, in combination:
a current fed radiator extending in a first direction and connected
to an electrically conductive outer RF transfer member, said outer
transfer member being adapted for affixation to said first side of
the glass plate;
an electrically conductive RF inner transfer member adapted for
affixation to said second side of the glass plate in alignment with
said outer transfer member;
an electrical connector having a main electrical contact and a
ground contact and being adapted for affixation adjacent said
second side of the glass plate with said main electrical contact in
engagement with said inner transfer member;
an electrically conductive field-cancelling member adapted for
location on said second side of the glass plate adjacent to but in
electrically spaced relation to said inner transfer member and
extending in a direction that is significantly different from said
first direction;
said field-cancelling member having a first non-volume containing
portion thereof on one side of the inner transfer member and a
non-volume containing and substantially balanced second portion on
the other side of the inner transfer member; said field-cancelling
member being operative to cancel the electromagnetic field in the
plane of the field-cancelling member;
said ground contact of said electrical connector being adapted for
engagement with said field-cancelling member; and
said electrical connector also including means for coupling said
electrical wiring to said main contact and to said ground contact.
.Iaddend. .Iadd.
15. In an antenna for mounting on a motor vehicle's glass plate
with a radiator extending from a first side of the glass plate and
with electrical wiring extending from the opposite, second side of
the glass plate whereby energy is transferred through the glass
plate and the drilling of a hole for connecting the radiator to the
electrical wiring is unnecessary, the improvement comprising, in
combination:
a current fed radiator extending in a first direction and connected
to an electrically conductive outer RF transfer member, said outer
transfer member being adapted for affixation to said first side of
the glass plate;
an electrically conductive RF inner transfer member adapted for
affixation to said second side of the glass plate in alignment with
said outer transfer member, said electrical wiring adapted for
location on said second side of the glass plate including a said
wire and a ground wire;
means for coupling said main wire to said inner transfer
member;
an electrically conductive field-cancelling member adapted for
location on said second side of the glass plate adjacent to but in
electrically spaced relation to said inner transfer member and
extending in a direction that is significantly different from said
first direction;
said field cancelling member having a first non-volume containing
portion thereof on one side of the inner transfer member and a
non-volume containing and substantially balanced second portion on
the other side of the inner transfer member; said field-cancelling
member being operative to cancel the electromagnetic field in the
plane of the field-cancelling member; and
means for coupling said ground wire to said field-cancelling
member.
Description
BACKGROUND OF THE INVENTION
The present invention concerns a novel antenna and, more
particularly, an antenna for mounting on a glass plate with the
radiator extending from one side of the glass plate and with the
electrical wiring extending from the opposite side of the glass
plate whereby energy is transferred through the glass plate and the
drilling of a hole for coupling the radiator to the electric wiring
is unnecessary.
Vehicle owners are generally apprehensive about drilling holes in
their vehicles and for that reason a window-mounted antenna which
transfers RF energy through the glass is desirable. One prior art
type of on-glass antenna is disclosed in U.S. Pat. No. 4,238,799.
This prior art antenna utilizes a radiator that must be voltage
fed, requiring the radiator to be an electrical half wavelength or
multiples thereof. Since the feed point of the radiator is also the
mounting point, this places the high impedance or high voltage
point directly on the glass mounting surface.
While glass itself is a good low loss insulator, when rain and snow
mix with contaminants such as dirt and salt are introduced on the
glass surface, a serious degrading of performance will result
because of the detuning and loss. This condition becomes worse as
the frequency of operation is increased. In accordance, with U.S.
Pat. No. 4,238,799, in order to voltage feed the radiator, which is
affixed to the outside of the glass, a coupling box containing an
LC resonant circuit is attached to the inside of the glass. This
resonant circuit inherently has some loss. The loss increases at
this circuit becomes detuned.
It is an object of the present invention to provide an on-glass
antenna that alleviates many of the problems concomitant with the
prior art on-glass antenna disclosed in U.S. Pat. No.
4,238,799.
Another object of the present invention is to provide an on-glass
antenna that is simple in construction and is easy to
manufacture.
A further object of the present invention is to provide an on-glass
antenna in which contaminants and water will have the least effect
on performance and detuning.
A still further object of the present invention is to provide an
on-glass antenna having a relatively wide band.
Other objects and advantages of the present invention will become
apparent as the description proceeds.
SUMMARY OF THE INVENTION
In accordance with the present invention, an antenna is provided
for mounting on a glass plate with a radiator extending from one
side of the glass plate and with an electrical connector and
electrical wiring extending from the opposite side of the glass
plate. In this manner, energy is transferred through the glass
plate and the drilling of a hole for connecting the radiator to the
electrical connector is unnecessary.
The improvement of the present invention comprises a current fed
radiator that is connected to an electrically conductive outer
transfer plate. The outer transfer plate is adapted for affixation
to one side of the glass plate.
An electrically conductive inner transfer member is adapted for
affixation to the other side of the glass plate in alignment with
the outer transfer plate.
An electrically conductive field-cancelling member .Iadd.having
non-volume containing portions .Iaddend.is provided for affixation
to the other side of the glass plate in a spaced relation to the
inner transfer member. On the other side of the glass plate, there
is also provided an electrical connector having a main electrical
contact and a ground contact. The main electrical contact is
adapted for engagement with the inner transfer member and the
ground contact is adapted for engagement with the field-cancelling
member. The electrical connector also includes means for coupling
the electrical wiring to the main contact and to the ground
contact.
In the illustrative embodiment, the current fed radiator comprises
a one-quarter wavelength radiator, and greater bandwidth is
provided by cophasing multiple radiators. The multiple radiators
are spaced elements which are generally parallel to each other and
are adapted for extension at an angle of about 45.degree. with
respect to the glass plate.
In the illustrative embodiment, the outer transfer plate comprises
a weather-resistant carrier having an electrically conductive metal
plate member on its underside for affixation to the one side of the
glass plate. The inner transfer member comprises an electrically
conductive tape member for affixation to the other side of the
glass plate. The field-cancelling member comprises a pair of
electrically conductive tape members for affixation to the other
side of the glass plate in spaced relationship to and on opposed
sides of the inner tape member.
In the illustrative embodiment, the ground contact comprises a pair
of electrical contact elements with one of the pair being adapted
for engaging one of the field-cancelling members and the other of
the pair being adapted for engaging the other of the
field-cancelling members. The electrical wiring comprises an RF
coaxial cable having a central conductor and a surrounding ground
conductor. The coupling means comprises means for coupling the
central conductor to the main contact and also means for coupling
the ground conductor to the ground contact.
A more detailed explanation of the invention is provided in the
following description and claims, and is illustrated in the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective exploded view of an on-glass antenna
constructed in accordance with the principles of the present
invention;
FIG. 2 is a diagrammatic view of the on-glass antenna of FIG. 1;
and
FIG. 3 is a graph showing a standing wave ratio/bandwidth
comparison between a commercial prior art on-glass antenna and an
antenna constructed in accordance with the principles of the
present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
Referring to FIGS. 1 and 2, the glass plate window 10 of a vehicle
is illustrated therein, preferably the rear glass window of the
vehicle, and there is a quarter wavelength radiator 12 positioned
on the exterior surface 10a of window 10. It is preferred that
radiator 12 comprise a pair of cophased quarter wavelength elements
12a and 12b, which are spaced in parallel to each other and extend
generally at an angle of about 45.degree. with respect to the glass
plate 10. Although no limitation is intended, in the illustrative
embodiment the on-glass antenna is used for cellular mobile
telephone transmission and reception, and elements 12a and 12b are
each 3 inches in length and are spaced 1 inch from each other.
Radiator 12 (i.e., elements 12a and 12b) are mounted on an outer
transfer plate 14 which comprises a plastic weather-resistant
carrier 15 having an electrically conductive metallic plate 15a. In
the illustrative embodiment, the metallic plate 15a has a dimension
of 5/8 inch by 15/8 inches, and elements 12a and 12b are in
electrically conductive relationship to the metal plate 15a. Outer
transfer plate 14 is affixed to the outer surface 10a of glass
window 10 by a suitable adhesive 15b, such as a pressure-sensitive
adhesive which is applied at the factory and is covered with
tear-off paper strips.
The remaining portions of the antenna assembly are located on the
inside of the vehicle, i.e., on the opposite surface 10b of the
glass window 10. Such elements include an electrically conductive
inner transfer plate 16, formed of a metal tape 16a having a
pressure-sensitive adhesive surface 16b which enables the metal
tape to be affixed to surface 10b of glass plate 10. It is
preferred that inner transfer plate 16 have the same dimension as
outer transfer plate 14 and that the transfer plates 14 and 16 be
aligned with each other so as to align inner transfer plate 16 with
the radiator 12.
A pair of field-cancelling electrical conductive members 18 and 20
are provided. These members 18 and 20 comprise electrically
conductive metal tapes, each preferably being equal in size and, as
illustrated most clearly in FIG. 1, these tapes are spaced from
each other and from the interior transfer plate 16 and are
positioned on opposite sides of interior transfer plate 16. Metal
tapes 18 and 20 have a pressure-sensitive surface which enables
them to be affixed to surface 10b of glass plate 10. Although no
limitation is intended, in the illustrative embodiment, each of
field-cancelling members 18 and 20 have a dimension of 5/8 inch by
27/8 inches. The field-cancelling conductors are in a horizontal
plane and operate to cancel each other out, thus effectively not
radiating in that horizontal plane. As a result, radiation is
consistent in the vertical plane only.
Alternatively, the field-cancelling electrical conductive members
18, 20 may comprise a pair of conductive wires or fingers which
extend outwardly from an electrical connector 20 described below,
with the wires or fingers extending horizontally. As another
alternative, members 18, 20 may be wires attached on the inside of
the car to a location adjacent the window but not on the
window.
An electrical connector 19 is provided for coupling an RF coaxial
cable 21 from the transmitter/receiver to the antenna. In the
illustrative embodiment, the coaxial cable 21 is a conventional 50
ohm line having a central main conductor 21a and a surrounding
ground conductor 21b. A conventional RF coaxial cable female
receptacle 22 is carried by electrical connector 19. The outer
circumference 22a of female connector 22, which conventionally
forms the ground connection, is conductively connected to a pair of
electrically conductive metal fingers 24 and 26. The central
conductor 28 of RF coaxial female connector 22 is fastened to
intermediate electrically conductive finger 30. Connector 19 has a
surface 32 which is adapted for adhesive connection to surface 10b
of glass plate 10, directly under inner transfer plate 16. When so
aligned, intermediate finger 30 will be in electrical engagement
with inner transfer plate 16, finger 24 will be in electrical
field-cancelling conductor 18 and finger 26 will be in electrical
connection with field-cancelling conductor 20. In order to provide
secure electrical connections, fingers 24, 26 and 30 are formed of
copper sheet material having a spring-like resilience so that when
connector 19 is fastened to surface 10b of glass window 10, the
fingers 24, 26 and 30 will press tightly against the respective
conductive tapes.
Alternatively, inner transfer plate 16 may comprise an electrically
conductive member having a lip extending toward connector 19 for
receiving connector 20 and enabling it to be affixed to the inner
transfer plate 16 and held in place therewith. Electrical connector
19 includes a plastic housing 32 defining an opening for receiving
the coaxial cable from the transmitter/receiver.
It can be seen that the illustrative embodiment utilizes a quarter
wave current fed radiator with two field-cancelling conductors. The
field-cancelling conductors substitute for a ground plane, as is
required in prior art constructions. By being current fed, the
quarter wave radiator makes the radiator mounting spot the low
impedance and low voltage point. In this manner, contaminants and
water will have the least effect on performance and detuning. This
arrangement can be designed to match the coaxial 50 ohm line
directly, thereby eliminating the LC circuit that is required in
the prior art construction disclosed in U.S. Pat. No.
4,238,799.
It has been found that by using two radiator elements 12a, and 12b,
excellent omnidirectional characteristics are obtained and a
relatively wide bandwidth is achieved. The two cophased radiators
minimize the possibility of undesirable space diversity by which
two signals arriving out of phase at the antenna at the same time
may cancel each other.
Referring to FIG. 3, a comparison is shown for the on-glass antenna
of FIG. 1 (illustrated in full line 36a) and the prior art Antenna
Specialist/Avanti APRD 850.3T "on-glass" antenna (illustrated in
dotted line 38a). The Antenna Specialist/Avanti antenna is a
commercial prior art antenna constructed along the lines of the
antenna disclosed in U.S. Pat. No. 4,238,799. It can be seen that
in the cellular transmission/reception band, the bandwidth of the
antenna of FIG. 1 is substantially greater than the bandwidth of
the prior art on-glass antenna.
Although two radiator elements 12a and 12b are desirable, in
another embodiment a single radiator, that is centrally positioned
with respect to outer transfer plate 14, is provided. The single
radiator element 12 is also a quarter wavelength current fed
radiator, and in the illustrative embodiment is 3 inches in length
for cellular mobile phone transmission/reception. When affixed to
surface 10b of glass window 10, it extends generally at an angle
that is about 45.degree. with respect to the window 10.
Alternatively, radiator elements may be stacked to obtain higher
gain at the sacrifice of bandwidth.
Although no limitation is intended, in the illustrative embodiment,
the space between the end 34 of field-cancelling conductor 18 and
end 36 of interior transfer plate 16 is 1/2 inch. Likewise, the
space between end 38 of field-cancelling conductor 20 and end 40 of
interior transfer plate 16 is 1/2 inch.
Although illustrative embodiments of the invention have been shown
and described, it is to be understood that various modifications
and substitutions may be made by those skilled in the art without
departing from the novel spirit and scope of the present
invention.
* * * * *