U.S. patent number 3,708,796 [Application Number 05/081,062] was granted by the patent office on 1973-01-02 for electrically controlled dielectric panel lens.
Invention is credited to Bony Gilbert.
United States Patent |
3,708,796 |
Gilbert |
January 2, 1973 |
ELECTRICALLY CONTROLLED DIELECTRIC PANEL LENS
Abstract
The apparatus and process for phase shifting a radiated
microwave includes passing the microwave beam through a dielectric
panel in which is imbedded at least one plane network of conductive
leads running parallel with the electric field of the incident
wave. Switches mounted on each lead are spaced from each other at
distances less than two wavelengths in the dielectric material, of
the incident energy. By these switches, the leads may be divided in
little sections.
Inventors: |
Gilbert; Bony (Issy,
FR) |
Family
ID: |
9041549 |
Appl.
No.: |
05/081,062 |
Filed: |
October 15, 1970 |
Foreign Application Priority Data
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|
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Oct 15, 1969 [FR] |
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6935239 |
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Current U.S.
Class: |
343/754; 343/909;
343/756 |
Current CPC
Class: |
H01Q
3/46 (20130101); H01Q 15/02 (20130101) |
Current International
Class: |
H01Q
15/00 (20060101); H01Q 3/46 (20060101); H01Q
15/02 (20060101); H01Q 3/00 (20060101); H01q
019/06 () |
Field of
Search: |
;343/757,754,755,854,909,756 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lieberman; Eli
Claims
I claim:
1. A lens apparatus for phase shifting a wave transmitted by a
microwave radiating source, comprising at least one dielectric
panel interposed across the path of the beam of microwave energy,
said at least one dielectric panel including at least one network
of conductive leads imbedded therein, throughout the panel, and
located in planes parallel to the electric field vector of the
incident wave, and switches mounted on each said conductive lead
and spaced apart thereon by a distance no more than twice the
wavelength, in the dielectric material, of the radiated incident
energy, allowing the conductive leads to be either divided in
sections or not divided along the whole length of the panel, said
dielectric panel having a thickness which is a multiple of a half
wavelength, in the dielectric material, of the radiated microwave
energy, to prevent any reflection of the incident wave.
2. A lens apparatus for phase shifting a wave transmitted by a
microwave radiating source, comprising at least one dielectric
panel interposed across the path of the beam of microwave energy,
said at least one dielectric panel including at least one network
of conductive leads imbedded therein, throughout the panel, and
located in planes parallel to the electric field vector of the
incident wave, and switches mounted on each said conductive lead
and spaced apart thereon by a distance no more than twice the
wavelength, in the dielectric material, of the radiated incident
energy, allowing the conductive leads to be either divided in
sections or not divided along the whole length of the panel, said
switches including diodes controlled by a control voltage to render
such diodes conductive, said control voltage being supplied to the
diodes through said conductive leads, there being a plurality of
said dielectric panels placed behind one another across the path of
the beam, said control voltage being selectively applied to each
conductive lead to vary the phase shifting of said wave from
0.degree. to 360.degree..
3. A lens apparatus as claimed in claim 2, which includes a first
set of said dielectric panels arranged behind one another across
the path of the incident beam, a polarization device operating to
rotate through 90.degree. the plane of polarization of the wave and
a second set of dielectric panels arranged behind one another
across the path of the beam, the conductive leads of said second
set of panels being orthogonal to the conductive leads of the first
set of panels.
Description
BACKGROUND OF THE INVENTION
This invention relates to a process for phase-shifting, as
required, a beam emitted by a microwave radiating source, and also
to the applications of such process to the design and development
of structures capable of changing the direction of a beam from a
microwave source, such structures being adapted for use as
electronic-scanning equipment.
A process for focusing or deflecting a wave from a microwave
radiating source is already known in the prior art and consists in
interposing in the wave path a lens or active reflector consisting
of similar juxtaposed elements, each consisting of a receiving
antenna and a wave-guide. The deflection brought about by the lens
or active reflector is altered by the effect of phase-shifters
mounted in each wave-guide.
This process has many drawbacks which prevent it from vying
successfully with known mechanical-scanning devices. One of these
drawbacks is that the very small size of the juxtaposed antennas
and wave-guides making up the active lenses require very close
manufacturing tolerances and a lossless material. It should also be
pointed out that the control leads of all these antennas and
wave-guides are very large in number and that adjusting and
checking them is a tricky business.
The main object of the present invention is to eliminate the
drawbacks of the previous process and to provide a process for
changing effectively, as required, the direction of a beam emitted
by a microwave radiating source. This process also eradicates the
constraints of mechanical scanning.
Another object of the present invention is to provide a process for
phase-shifting, as required, the incoming beam from a microwave
radiating source by interposing one or several dielectric panels in
the path of the electromagnetic wave. Each panel includes one or
several plane networks of conductive leads running parallel with
the electric field of the incident wave which can be connected and
disconnected, as required, by means of switches located on these
leads at distances less than 2.lambda., where .lambda. is the
wavelength, in the dielectric material, of the radiated incident
energy.
A further object of the present invention is to provide an
apparatus and process for phase-shifting a beam emitted from a
microwave radiating source which includes passing the beam through
a dielectric panel and connecting and disconnecting, as required,
each conducting lead by switches located thereon and spaced, at
distances less than twice the wave-length, in the dielectric
material, of the radiated microwave energy; these leads
constituting a plane network imbedded in the panel's dielectric and
parallel with the field of the incident wave.
These and other objects of the present invention will be readily
apparent upon a consideration of the following specification taken
in conjunction with the accompanying drawings in which:
FIG. 1 is a block diagram illustrating a phase shifting apparatus
of the present invention;
FIG. 2 is a view in front elevation illustrating one of the
dielectric panels of FIG. 1;
FIG. 3 illustrates two spaced dielectric panels having orthogonally
arranged conductive networks;
FIG. 4 is a diagrammatic illustration of an active lens constructed
in accordance with the present invention;
FIG. 5 is a diagrammatic illustration of an active reflector
constructed in accordance with the present invention; and
FIG. 6 illustrates a second embodiment of an active reflector
constructed in accordance with the present invention.
For purposes of this invention, a "panel" is any element with a
plane, or locally like surface, which lies throughout to a plane
with respect to the wave-length of the radiated microwave
energy.
It follows that the leads forming the "plane network" imbedded in
the dielectric of a panel likened to a plane are to be located at
the intersections of the panel in planes parallel with the electric
field and this, throughout the said panel.
The conductive leads making up the plane networks imbedded in the
dielectric and which can be, as required, joined or divided in
sections by switches located thereon, are selected so as to
constitute self-inductive barriers from the standpoint of
microwaves. These leads are arranged to produce any of the effects,
known of the prior art, obtainable by setting conductive leads in
dielectric panels.
In the aforesaid processes of the invention, the switches are on
conductive leads constituting the plane networks, the switches
preferably being spaced apart, within the dielectric at one quarter
of the wavelength, in the dielectric material, of the radiated
microwave energy.
The panels employed to implement the processes of the invention
(FIGS. 1 and 2) consist of dielectric sheets 10 in which are
imbedded plane networks of conductive leads 12 which may be
interrupted or not, as required, by means of switches 14 located on
the leads in the dielectric and spaced less than twice the
wavelength from the radiated microwave energy. These leads
constitute a plane network imbedded in the dielectric of the panel
which is parallel with the field 16 of the incident wave from a
microwave source 18.
When interposing concurrently several panels in the path of a
microwave wave, these panels may be positioned one behind the other
in the path of the microwave and suitably apart from each other
while, of course, leaving the respective networks of leads,
(connected and disconnected as required) parallel with the electric
field of the incident wave. Alternatively, the panels may be
positioned with the sides thereof, which are parallel to the
networks of leads, contacting, the networks of leads being also
parallel with the electric field of the incident wave.
Rather than setting several panels one behind the other, according
to the invention, it is also feasible to devise a single multiple
panel by imbedding in a dielectric sheet comprising several
successive planes, several planar networks of leads which can be
connected and disconnected as required.
When interposing concurrently several panels, according to the
process of the invention, across the path of two cross-polarized
microwaves that can be phase-shifted as required, the networks of
leads, connected and disconnected as required, must be placed so as
to be parallel with the electric fields of both incident waves,
i.e., normal to one another as illustrated in FIG. 3. Here panels
19 and 20 are arranged with orthogonal leads 12.
The switches spaced on the leads and imbedded in the dielectric
panels are controlled either separately or, preferably, in groups.
Electrically or electronically controlled switches are preferred,
and each switch is controlled either through its relevant lead, or
leads normal to the electric field of the incident wave.
The switches 14 may consist of diodes controlled by a voltage
sufficient to make them conductive or not. The diodes in series on
the same lead are mounted in the same direction and concurrently
controlled by the same voltage on input 22. Of course, several rows
of diodes, of one or several panels, can be controlled concurrently
by the same voltage source 24 as illustrated in FIG. 1.
To do away with the reflections caused by interposing the
dielectric panels, according to the process of the invention,
across the path of the beam, all that is required is to space apart
two or several parallel panels as previously described in such a
way that the reflections arising from each panel combine in regard
to amplitudes and relative phases such that there is no longer any
reflected wave. This may be achieved using the so-called "sandwich
technique" known to the art.
To do away with the reflections, it is also possible, as known in
the prior art, to make up the panel from dielectric sheets whose
width is a half-wavelength multiple, within the dielectric, from
the radiated microwave energy. This is done, as stated above, by
imbedding, in this sheet of specific thickness, one or several
networks of conductive leads, connected and disconnected as
required, and arranged in planes parallel with the electric field
of the incident wave.
The applicant has discovered that the effect on the phase shift of
an incident wave of a planar network of parallel leads, imbedded in
a dielectric panel, changes when the leads are interrupted at
intervals sufficiently close that there are no longer any induced
currents in the leads. For instance, when the state of a dielectric
panel including a planar network of parallel conductive leads,
selected and positioned across the path of the incident wave so as
not to give rise to any reflection and virtually no phase shift
thereon, is altered through interruption of the conductive leads at
intervals of one quarter wavelength, in the dielectric material, a
substantial phase shift of the said incident wave is brought
about.
By way of non-limitative example, a sandwich panel is described
hereunder which permits implementing the process for changing, as
required, the phase shift of a beam incoming from a microwave
radiating source.
In two sheets of fiber-glass-reinforced polyester, each 6.5 mm
thick, forming a laminate whose dielectric constant is 3.5, copper
leads of 0.5 mm gauge were imbedded at mid-thickness of each sheet
to a pitch of 30 mm. Standard silicon diodes were inserted and
spaced to a pitch of 26 mm in those leads, their connections being
soldered to the end of the sections of the leads. Such diodes were
all connected in the same direction on all leads, thus making up a
circuit which becomes conductive when supplied with a 20-volt
potential difference at the proper polarity and, on reversal of the
latter, this circuit becomes non-conductive. This diode control
voltage is handily applied to the tips of the leads which are on
the side of the panel and were made to protrude for this very
purpose.
These two sheets, so fitted with wired-on diodes, are identical and
were spaced parallel 31 mm apart; the leads being likewise
parallel.
Such a panel, as with any sandwich panel, is matched at all times,
i.e., no objectionable spurious reflections occur irrespective of
the state the diodes in the sheet are in, provided, however, that
in both sheets, the corresponding diodes are in the same state.
The panel operates as follows. The phase shift varies according to
the state of the diodes in both sheets. It peaks when the diodes
are cut off and drops to a minimum when the diodes are conducting.
The phase shift is not identical throughout the surface of the
panel when some banks of diodes are cut off and some conducting.
The phase shift peaks where portions of the wave have come across
cut-off banks and is minimal across conducting banks. This shows
how it is possible, in accordance with the teachings of the
invention, to control the phase shift of an incident wave with such
a panel.
When a 3 GHz wave passes through this panel, the phase shift is
60.degree. when the diodes are cut off and 6.degree. when
conducting.
The present invention provides a phase shifting unit which is much
simplified and has tolerance limits which are definitely less
stringent than known units. The panels and sheets are readily
assembled rigidly and fully enclosed. Losses in the dielectric can
easily be made very small.
The outer connections to the radiating unit are fewer, and the
leads imbedded in the dielectric fulfil two functions; function
control of diodes and function microwave components. The unit is
fully integrated, there being no need to subdivide it into several
modules. In addition, with the diodes being connected in series on
each lead, the control currents are low, and the microwave energy
flowing in the diodes matches the energy required for correcting
the disconnections. This accounts for but a small portion of the
aggregate energy conveyed by the incident wave. The upshot is that
the losses ascribable to the diodes are very small, even when using
standard and inexpensive diodes.
The principles and structures heretofore described can be employed
to form lenses which are active in the plane normal to the network
of connected and interrupted leads, and which provide focusing and
deflecting in all planes and active reflectors.
Provision of such an active lens, according to the invention, is
achieved merely by forming a device whereby the phase shift of an
incident wave is varied locally from 0.degree. to 360.degree. in as
small increments as required. This is accomplished by the proper
selection of dielectric panels of a given thickness, including
leads interrupted, as required, by the banks of diodes described
above, and by setting a number of such panels of the type
illustrated by FIG. 2, such phase shifts of the incident wave are
brought about, as required, from 0.degree. to 360.degree.. A
computer may be employed to control the switching voltages and
accomplish phase shifting from 0.degree. to 360.degree..
The incident wave is split into as many parallel strips as there
are leads including banks of diodes. The phase shift is uniform on
each strip and may vary from one to the other and, by acting upon
the diodes' control voltage, the incident wave can be focused or
deflected, or both in the plane normal to the disconnected leads.
Thus is achieved an active lens normal to the leads.
To constitute an active lens that will focus and deflect in all
planes, all that is needed is to set two active lenses 26 and 28,
as described above, one behind the other so that the leads of the
former be normal to the leads of the other and both lenses be
separated by a device 30 operative to rotate the polarization of
the incident wave through 90.degree. (FIG. 4). It follows that both
focusing and deflection can be separate functions and that a
conventional device, such as a reflector or a standard lens can
take care of focusing.
An active reflector, according to the invention, is readily
constructed by the provision of an active lens 32 formed from a
plurality of panels 10 arranged one behind the other as described
above and, setting the active lens in front of a mirror 34 as
illustrated by FIG. 5.
Another active reflector is also achievable, according to the
invention, by using one or several dielectric panels 36 comprising
at least two planar networks 38 and 40 of perpendicular conductive
leads, and setting this special-type panel opposite a mirror
including a rotatory-polarization device 42 (FIG. 6). The leads 38
parallel the electric field of the incident wave while the leads 40
are parallel, after reflection, with the electric field of the
wave.
* * * * *