U.S. patent number 3,691,563 [Application Number 05/097,147] was granted by the patent office on 1972-09-12 for dual band stripline antenna.
This patent grant is currently assigned to Motorola, Inc.. Invention is credited to Philip L. Shelton.
United States Patent |
3,691,563 |
Shelton |
September 12, 1972 |
DUAL BAND STRIPLINE ANTENNA
Abstract
A dual band antenna is disclosed in which the radiating elements
for each band are slots in a conductive sheet and in which the
slots are fed by wave guides and stripline distribution means. The
conductive sheet is an outside layer of a sandwich comprising two
outside conductive layers and two sheets of dielectric between said
outside layers and said stripline distribution means or
transmission line, between the dielectric sheets. Two additional
similar sandwiches are used having therein transmission lines and
couplings thereto for the two waves to be radiated. The outside
layer of a middle sandwich is in close contact with an outside
layer of the two other sandwiches, whereby there is no radiation
from between the sandwiches. To make this close contact possible,
the sandwiches are made with flat smooth outside surfaces and the
sandwiches are not held together in a manner that may cause a bumpy
surface.
Inventors: |
Shelton; Philip L. (Scottsdale,
AZ) |
Assignee: |
Motorola, Inc. (Franklin Park,
IL)
|
Family
ID: |
22261487 |
Appl.
No.: |
05/097,147 |
Filed: |
December 11, 1970 |
Current U.S.
Class: |
343/771;
333/238 |
Current CPC
Class: |
H01Q
5/42 (20150115) |
Current International
Class: |
H01Q
5/00 (20060101); H01q 013/10 () |
Field of
Search: |
;343/767,771
;333/84M |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lieberman; Eli
Claims
What is claimed is:
1. A dual antenna comprising:
a plurality of sandwiches, each sandwich including two conducting
layers, two dielectric sheets between said conducting layers, and a
transmission line between each two dielectric sheets,
the outer surface of at least one of said conducting layers being
smooth and level,
means for holding said sandwiches together with said smooth layers
in contact,
means for applying radiatable energy to one of said sandwiches,
means to so couple said sandwiches that said energy arrives through
said contacting layers to another of said sandwiches, whereby due
to the contact of said smooth layers, energy is not radiated out
from between said sandwiches,
one of the two conducting layers of said another sandwich is an
outer conductive layer having two pluralities of holes
therethrough,
one of said plurality of holes being the ends of respective wave
guides through said another sandwich and energized by said
transmission line in said one sandwich, and
said other plurality of holes being energized by the transmission
lines in said another sandwich.
2. The dual antenna of claim 1 in which one of the conducting
layers of said one sandwich is an outer conductive layer and said
one sandwich includes at least one wave guide therethrough for
energizing said transmission line in said other sandwich, and
means to apply energy to at least one wave guide and to said
transmission line in said one sandwich.
3. The dual antenna of claim 2 in which said means to apply energy
comprises a third sandwich having outer layers of conductive
material, one layer thereof being smooth and level and being held
against said one sandwich,
said third sandwich includes two dielectric sheets and a third
transmission line between said last mentioned dielectric
sheets,
wave guide means for applying energy to said third transmission
line through a hole in the outer conductive layer of said third
sandwich, and
coaxial means for applying energy to the transmission line of said
one sandwich through said third sandwich.
4. The dual antenna of claim 3 in which the outer conductor of said
coaxial line is connected to a conductive layer of said one
sandwich, and
the inner conductor of said coaxial line is conductively connected
to the transmission line in said one sandwich.
5. The dual antenna of claim 4 in which the conductor of said wave
guide is connected to the outer conductive layer of said third
sandwich.
Description
BACKGROUND
It is often necessary in radio direction finding operation to
transmit waves in two different wave bands into the same space and
often in the same direction. While prior art devices for so
radiating waves in different bands are known, they are often large,
bulky devices using high frequency plumbing for the energization
thereof, which are difficult and expensive to make.
It is an object of this invention to provide an improved dual radio
wave radiating device.
It is an object of this invention to provide a dual radio wave
radiating device that can be made to a great extent by printed
circuit techniques.
SUMMARY
According to the invention, a structure comprising three sandwiches
in close electrical contact are provided. Each sandwich includes
two outside layers of a conductive material such as copper and two
intermediate sheets of insulating material between the outside
layers and a middle layer comprising a transmission line of the
stripline type which is used as an energy distribution means. The
top or first layer has a plurality of parallelly arranged slots cut
therethrough to act as radiator elements for waves of one frequency
band, and another plurality of parallelly arranged slots cut
therethrough to act as radiator elements for the waves of another
frequency band. The first plurality slots may all be of the same
size but different in size from the slots of the second plurality
thereof, and the slots of the two pluralities thereof may be
arranged perpendicularly to each other. The first plurality of
slots may be continuations of holes through the two dielectric
sheets and through the other outside sheet, the insides of the
holes having conductive material deposited thereon and electrically
connected to the two outside layers to produce wave guides. The
other plurality of slots extend only through the outside layer and
the intermediate layer of the top sandwich acts only as a stripline
feed means or distribution or transmission line for the slots of
the other plurality thereof. The conductive top layer of the middle
or second sandwich has slots in position to register with the wave
guide through the top sandwich. The center layer of a middle
sandwich is a stripline transmission line for feeding the slots in
the top layer thereof. Wave guides also extend through the middle
sandwich and are positioned to feed the stripline middle layer of
the top sandwich. The top layer of the bottom sandwich has slots
therein positioned to register with the wave guides through the
middle sandwich and the center layer of the bottom sandwich is a
stripline transmission line to feed the wave guides through the
center layer. A hole is provided through the bottom layer for
connection to the outside layer of the middle sandwich of means to
feed the center layer of the middle sandwich. The transmission line
in the bottom sandwich is fed by a wave guide coupled through a
hole in the bottom layer of the bottom sandwich to the transmission
line in the bottom sandwich. Each of the sandwiches has smooth,
level outside layers which are to be in contact whereby upon
contact to the three sandwiches, they are in good electrical
contact, whereby radiant wave energy cannot leak out from between
the several sandwiches. This good electrical contact is provided by
fastening the several layers of the sandwiches together in a manner
which does not provide bumps or irregularities on the surface of
the sandwiches as if the sandwiches were affixed together by
rivets. The several layers of the sandwiches are therefore glued or
otherwise bonded together and the insides of the holes through the
sandwiches have conductive material plated thereon. Since the
conductive parts of the several sandwiches can be made by printed
circuit techniques, and since the holes in the several sheets of
dielectrics are straight through and of simple shape, the disclosed
dual band antenna can be made quite economically in single or large
quantities.
DESCRIPTION
The invention will be better understood upon reading the following
description in connection with the accompanying drawing in
which:
FIG. 1 is a plan view of the antenna embodying this invention,
FIG. 2 is a section of FIG. 1 on line 2--2 thereof,
FIG. 3 is a section of FIG. 1 on line 3--3 thereof,
FIG. 4 is a fragmentary view of the transmission line of the top
sandwich showing the positions of the several slots in the top
conductive layer in dotted lines for explanatory purposes, and
FIG. 5 is a fragmentary view of the transmission line of the middle
sandwich and also showing the relative positions of the several
slots to the transmission line in dotted lines.
Turning first to FIGS. 1 and 2, a top sandwich 10, a middle
sandwich 12 and a bottom sandwich 14 are shown. The top sandwich 10
comprises a top conductive layer 16 and a bottom conductive layer
18. The top layer 16 has a plurality of slots 20 formed therein.
While 16 slots 20 are shown, there may be as many thereof as is
desired. While all of the slots 20 are shown as being parallel and
arranged along equidistant lines, the slots 20 may be arranged as
is desired. A second plurality of slots 22 are also formed through
the layer 16, the slots 22 being smaller than the slots 20 and
being arranged between and perpendicular to the slots 20. Again the
number and positions of the slots 22 may be as desired.
The sandwich 10 also comprises two sheets 24 and 26 of dielectric
material between the layers 16 and 18. Holes 28 of the same size
and shape as the slots 20 extend through the two sheets 24 and 26
and register with the slots 20. A stripline transmission line 30 is
positioned between the layers 24 and 26. The bottom layer 18 has
slots cut therethrough registering with the holes 28. The insides
of the holes 28 are plated in a known manner with a conductive
material, this conductive material being electrically connected to
the layers 16 and 18, whereby the holes 28 act as wave guides for
leading energy to be radiated to the radiating slots 20 as will be
further explained. The transmission line 30 is arranged in such
manner that it is insulated from the wave guides 28. A plurality of
holes 32, only one of which is shown in FIG. 2, is provided in the
bottom layer 18 for purposes to be described. The layer and sheet
16 and 24, the stripline 30, and the layer and sheet 26 and 18 are
fixed together as by gluing or otherwise bonding, the stripline 30
being so thin that it does not interfere with this fixing together,
whereby the outside layers of the sandwich are quite level and
smooth.
The middle sandwich 12 comprises an upper and a lower conductive
layer 34 and 36. The upper layer 34 has slots 38 therein
registering with the wave guides 28 but of a smaller area than the
wave guides 28. A wave guide 40, made like the wave guide 28,
extends through the layers 34 and 36 and through the intermediate
dielectric sheets 42 and 44 and registers with a hole 32. While
only one wave guide 40 is shown in FIG. 2, there may be as many
thereof as there are holes 32. A transmission line 46 extends
between dielectric sheets 42 and 44. The transmission line 46 is
insulated from the wave guide 40. A hole 48 is provided in the
bottom layer 36 so that the interconductor 50 of a coaxial line 64
may extend through the hole 48 and be insulated from the layer 36
and be connected to the transmission line 46. The layer 12 is made
like the layer 10 and has smooth and level outside surfaces.
The bottom sandwich 14 has an upper and a lower conductive layer 52
and 54. The layer 52 has a relatively large hole 56 therethrough
which is concentric with the hole 48, and as many holes 58 as there
are wave guides 40, the holes 32 and 58 being somewhat smaller in
area than the wave guides 40 and registering therewith. The hole 56
continues through the intermediate dielectric sheets 60 and 62 and
the bottom layer 54 and the coaxial cable 64 extends into the hole
56. The outside conductor of the coaxial cable is conductively
connected to the layer 36, and the inner-connector of the coaxial
cable 64 is connected to the conductor 50. A transmission line 66
is positioned between the sheets 60 and 62. A hole 68 is provided
in the bottom layer 54 and a wave guide 70 is conductively fixed to
the layer 54 around the hole 68.
In operation, radiant energy which is to be radiated by the slots
20 is applied by way of the coaxial conductor 64 and the
inter-conductor 50 to the transmission line 46 which supplies
energy to the wave guides 28 by way of the holes 38 by radiation,
in effect, across the dielectric sheet 42. The way that this is
accomplished may be understood upon observing FIG. 5. The
transmission line 46 has portions which extend across the wave
guide 28, the dotted lines in FIG. 5 representing the position of
the wave guides 28. The transmission line 46 is connected to the
pin 50, the length of the transmission line from the pin 50 to the
several wave guides 28 being such as to provide energy at the
desired phase relation to the several wave guides 28 and therefore
to the several slots 20 for radiation therefrom in a pattern in a
known manner. As is seen in FIG. 5, the connections comprising the
configuration whereby the transmission line 46 will not interfere
with other elements of the middle sandwich 12, such as the wave
guides 40, is due to the fact that the transmission line 46 may be
shaped in any convenient manner.
The slots 22 are fed by energy supplied through the wave guides 70.
This energy is radiated across the dielectric 62 to the
transmission line 66. The energy in line 66 is radiated across the
dielectric 60 to the wave guide or guides 40 through the holes 58,
only one of each being shown. The energy from the wave guide 40 is
radiated to the transmission line 30 through the hole 32 and the
energy in the transmission line 30 is radiated to the slots 22.
Attention is called to FIG. 4 in which a part of the transmission
line 30 is shown in relation to the holes 32 and the slots 20 and
22, the position of the latter being shown in dotted lines in FIG.
4. Again, the connections can be routed to avoid obstacles such as
the wave guides 28 in constructing the transmission line 30.
No energy that is fed to the coaxial line 64 or to the wave guide
70 leaks out between the sandwiches 10, 12 and 14, since the layers
18, 34, 36 and 52 are made very smooth and level whereby the
contact between these layers is a good electrical contact. While
the coaxial line 64 and wave guide 70 feeds are shown, whatever
feeds that are convenient may be used. The positioning and size and
shape of the slots 20 and 22 may be what is convenient for the wave
bands to be radiated in desired patterns.
While both groups of radiating slots 20 and 22 and their feed means
are shown and described, it will be clear that only one group of
slots 20 or 22 and the feed means therefor need be provided, or, if
both groups of slots and their feed means are provided, only one
group of slots may be energized, whereby only one group of slots
will radiate. Furthermore, the radiations from the two groups of
slots are independent of each other.
* * * * *