Radar reflector and scanner with electromagnetic programmable drive

Elements of a radar antenna are provided with one or more electromagnetic actuators capable of moving the elements (scanner or parabolic reflector), independently of the support system in response to electrical signals applied to the coils of the electromagnetic actuators.

BACKGROUND 
1. Field of the Invention 
This invention is directed to radar systems, in particular, and to a new 
and unique method and apparatus for selectively moving and/or 
repositioning a portion of the system thereby to direct the radar beam 
generated thereby, in particular. 
2. Prior Art 
There are many known devices and systems which are used in the provision of 
signals for scanning and/or tracking purposes. These systems are 
frequently referred to as radar systems. In the known systems, an 
electromagnetic signal is produced by an antenna and then focused and 
directed by appropriate dishes which take the form of parabolic 
reflectors, splash plates, or the like. Most of these existing systems are 
quite heavy, especially those devices used in ground installations. In 
airborne installations or the like, the support-structure is somewhat 
smaller but the antenna is likewise smaller. In operation, the basic 
concept of the radar scanner system is to provide an electromagnetic 
signal at the antenna. By scanning the antenna by means of a mechanical 
drive, the appropriate scanning operation can be effected. This scanning 
usually takes the form of rotation or nutation of the apparatus about the 
various axes so that the scan pattern can be controlled. 
In an alternative embodiment, the scanner splash plate can be driven, in a 
suitable fashion, to rotate or oscillate about its axis in conjunction 
with the reflector plate. This rotation can take place independent of or 
in conjunction with the rotation of the reflector. 
In the existing systems, some of which are described above, it is necessary 
to provide suitable electric motors which can drive the respective splash 
plate and/or reflector through gear trains or the like. These motors must 
be sufficiently accurately prepared and produced so as to provide the 
desired driving pattern to the reflector and/or the splash plate. Clearly, 
elaborate drive trains, bearing arrangements and the like are required. 
Moreover, because each of the elements can be driven as discussed, the 
respective reflector and/or splash plate must be fabricated of a 
sufficiently sturdy and rugged material so as to withstand the mechanical 
forces, torque and the like which can be applied thereto. Moreover, a 
suitable framework must also be provided which can withstand these same 
forces. 
As a consequence, the existing radar systems become relatively large, 
heavy, and cumbersome in order to operate in a reasonably reliable 
fashion. However, these same characteristics tend to make the systems 
bulky and unwieldy for many operations and proposed utilizations. 
Moreover, the existing systems tend to be quite expensive to fabricate and 
produce. 
SUMMARY OF THE INSTANT INVENTION 
This invention is directed to a radar system wherein the scanning operation 
is provided by using one or more coils, magnets and electromagnets to 
cause a portion of the splash plate or the reflector of a radar system to 
be selectively displaced. By disposing the coils, magnets and/or 
electromagnets in appropriate locations on the radar scanning mechanisms, 
an appropriate and planned pattern of movement of the radar system 
components can be effected which can be altered rapidly. The ability to 
change scanning frequency and pattern rapidly can assist in avoiding 
jamming of radar signals. 
By selectively displacing the radar system surfaces, the beam generated 
thereby can be selectively positioned. By using programmable control 
beams, exotic beam patterns can be generated by the system. The patterns 
can be essentially linear, conical, Lissajous figures, or the like. 
In addition, a relatively lightweight antenna system can be generated. 
Thus, this concept can be readily adapted to airborne antenna systems.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, concurrently, there is shown a partially 
broken away, schematic, representation of a radar system in accordance 
with the instant invention. In this embodiment, a radar dish 100 includes 
a typical parabolic reflector 101. However, in this instance, the 
reflector can be prepared from a lightweight material which provides for 
low inertia. While not limited thereto, the reflector can be made of 
graphite fibers or the like. Of course, any other suitable lightweight low 
inertial material can be utilized. For example, a fiberglass dish with an 
appropriate reflectorized surface is feasible. 
The standard fixed feed device 102 with a sub-reflector 103 is mounted to 
the radar system support mechanism (not shown) with a bolted flange or 
other means which enables the feed to be installed at a fixed location 
relative to the focal point of the reflector. This mounting can be adapted 
for selectively pointing the antenna in a particular direction in some 
embodiments. This mounting arrangement does not form a part on the 
invention, per se. 
Mounted to the fixed feed unit 102 is the support bracket 104 which 
includes a hub 104A which is adapted to be mounted contiguous with the 
feed element 102. While the support bracket 104 is depicted in the form of 
a "spider", it can take the form of some other component having a 
plurality of support arms or the like. In the embodiment shown in FIG. 2, 
four such arms are shown. However, it should be understood that more (or 
fewer) arms may be utilized. In fact, if a large number of magnetic 
devices (described infra) are utilized, the support 104 can take the form 
of a circular plate or the like. 
As seen in FIGS. 1 and 2, an electromagnetic device is mounted at the end 
of each of the bracket arms. As seen best in FIG. 1, an electromagnetic 
device 105 is mounted at the lower portion of support device 104 while 
another electromagnetic device 107 is mounted at the upper end of the 
support bracket 104. As shown in FIG. 1, the electromagnetic devices 
comprise a suitable coil, an armature and the like. This device is shown 
in greater detail hereafter. 
Also mounted at selected locations on the reverse side of reflector 101 are 
appropriate magnetic devices 116 and 117. These magnetic devices can be 
mounted directly to reflector 101 or they can be mounted on appropriate 
shims 106 and 108, respectively. It is submitted that the shims permit 
additional flexibility and less restrictive tolerances in the arrangement 
and mounting of the magnetic devices 116 and 117 to the reflector 101. 
That is, the magnet (or magnetizable material) can be mounted on the shim 
material in order to provide adjustment of the tolerances between the 
magnet and the electromagnetic coil, and so forth. Conversely, the magnets 
can be mounted directly on the reverse side of the reflector 101. In this 
instance, the magnets 116 and 117 can be configured and contoured to match 
the configuration of reflector 101. Conversely, the magnets can be mounted 
directly on to the reverse side of the reflector 101 and the bracket 104 
can be modified. For example, the ends of the bracket arms can be bent so 
that the electromagnet 105 or 107 is disposed in proper juxtaposition to 
the reflector. Of course, the positions can be reversed and the magnet can 
be mounted on the bracket 104 and the coil attached to the reflector 101. 
Moreover, the magnet, magnetic material, or the electromagnetic coil can be 
formed in or as a part of the reflector 101. In like manner, it is 
conceivable that the reflector 101 or the bracket 104 can be fabricated of 
magnetic material itself, in some instances, provided the appropriate 
control can be maintained. 
Referring now to FIG. 3, there is shown a more detailed illustration of one 
embodiment of the magnetic system apparatus. In this instance, a portion 
of the reflector 301 is shown. Mounted to the reflector is a suitable shim 
306. The shim can be mounted to the reflector by means of mechanical 
fasteners such as rivets or the like. Conversely, the shim 306 can be 
mounted to reflector 301 by means of any suitable adhesive such as an 
epoxy or the like. Mounted on the surface of shim 306 by fastners 315 is a 
magnet or armature of suitable magnetic material 316. This material (for 
example, soft iron, alnico, samarium cobalt or the like) can be mounted to 
the shim 306 by a suitable fastening means such as screws, adhesives or 
the like. The shape of the armature is not limited by the designs shown 
and can include an elongated shaft of magnetic material. 
Adjacent to this shim and magnetic strip is disposed an electromagnetic 
device 105. This device is mounted on the support bracket 304, a portion 
of which is shown. This apparatus includes an electromagnetic coil 310 
which is wound about a suitable core or support. (Of course, the coil can 
be independently wound as well.) The wires 311 extend from the coil 310 
for connection to any suitable electrical system to be described infra. 
On opposite sides of the coil 310 are provided soft rubber washers 312 and 
314. These rubber springs or washers which can be of any suitable flexible 
material or thickness, are used to allow the armature 316 to deflect when 
the magnetic coil 310 is activated. In addition, the soft rubber springs 
312 and 314 serve to shield the coil from dirt and moisture. 
The coil and rubber springs are mounted to bracket 304 by means of a 
appropriate mounting apparatus which includes, for example, bolt 307 and 
washer 308. The bolt 307 is threadedly attached to the magnet armature 316 
which is centrally located relative to coil 310. This armature 316 can be 
a permanent magnet which is selectively moved relative to the coil 310. 
Conversely, the magnet 316 can be a piece of magnetizable material which 
is selectively energized and magnetized by the activation of coil 310. 
A position control flexure device 309 is used to center the magnet within 
the coil. The snap ring 313 retains the coil 310 within the bracket 
housing. A non-magnetic washer 320 is held in place by bolt 307 to clamp 
the coil apparatus together. 
In like manner, a clamp sleeve 309 is provided as well. This sleeve is, 
preferably, fabricated of non-magnetic material and serves to hold the 
assembly together. 
Thus, in operation, an activation signal is selectively supplied, via wires 
311, to the coil 310. Activation of the coil operates to energize the 
electromagnetic apparatus, in a similar fashion to a speaker coil, and to 
effectively reposition (i.e. move) the reflector 301 (or reflector 101 in 
FIG. 1). That is, the armature is moved in response to the coil 
activation. Thus, the reflector is, effectively, repositioned relative to 
the electromagnetic beam which is applied by the feed device 102. 
Repositioning of the reflector, thus, has the effect of relocating or 
redirecting the beam produced by the radar system. 
By means of selectively activating different coils and the intended 
electromagnetic apparatus, is seen (see especially FIG. 1) that controlled 
deformation of the reflector 101 can be achieved. This controlled 
deformation can have the effect of controlling the positioning and 
direction of the beam produced by the radar system. 
The coils can be operated in an attract mode which will move the reflector 
toward the apparatus including the mounting bracket. Conversely, a 
repelling operation can be produced. Likewise, it is clear that a 
push-pull operation can be achieved. This would permit the deformation of 
the reflector to be increased to a larger degree while requiring only a 
relatively small change in position or movement. Likewise, by pulling on 
one magnet (e.g. device 107) and pushing on the opposite magnet (e.g. 
device 105), an exaggerated deformation or deflection of the reflector can 
be achieved. 
In addition, by utilizing a plurality of the magnetic apparatuses, (see for 
example FIG. 2) a circular movement or deflection of the reflector can be 
achieved. This deflection can be likened or considered to be a circular, 
wave-like motion in the reflector. Also, by appropriate control of the 
sequence of activation of the electromagnetic devices, horizontal 
sweeping, vertical sweeping, circular sweeping or any combination thereof 
can be achieved. 
Although not shown, per se, it is understood that the electromagnets can be 
driven by any suitable power source which is connected to the wires 311 
associated with the respective electromagnetic devices. Thus, a pattern 
can be stored in a suitable memory, such as a semiconductor memory, a tape 
drive, a disk drive or the like. This pattern can be used to appropriately 
activate the various magnetic apparatuses. Thus, the same pattern can be 
repetitively performed by a particular antenna system. Moreover, the same 
pattern can be applied to a plurality of antennas so that an entire bank 
of antennas can be performing the same pattern in a coordinated fashion, 
i.e. together or in a desired and correlated sequence. 
Referring now to FIG. 4, there is shown another embodiment of the 
invention. In this embodiment, the splash plate 410 is mounted to the 
reflector (such as reflector 101 in FIG. 1) by means of suitable and 
standard mounting struts 402. The struts 402 are mounted directly to the 
support plate 401 to which is mounted the support bearing 409. The support 
bearing 409 is mounted to the drive mechanism by means of bolts, rivets, 
welds or other suitable technique. 
In this embodiment, the magnets 404 are mounted to the support plate 401 by 
any suitable means. In the embodiment shown, the magnets 404 are mounted 
in a supporting cup 403 which is fabricated of any suitable material such 
as soft iron which has the preferred magnetic characteristics. 
In addition, the mounting bracket 408 is attached to the splash plate 410 
by suitable means such as nuts and bolts. The support plate 408 is also 
pivoted on the support bearing 409 to allow the splash plate to tilt (or 
pivot) in response to the action of the magnets. 
A suitable bellows 407 and 406 are provided to permit enclosure of the cup 
403 and the magnet 404 as well as the coil 405. The bellows permits 
flexure for movement of the support plate 408 (and thus splash plate 410) 
when the electromagnet device comprising the magnet 404 and the coil 405 
are selectively activated. Also, the bellows operates to keep dirt out of 
the magnetic apparatus. 
Again, it is seen that any pattern of electromagnetic devices can be 
prepared and mounted on the support 401 and the flexure plate 408. These 
electromagnetic devices can be controlled in the same fashion as the 
electromagnetic devices shown and described relative to FIGS. 1 through 3. 
As a consequence, the splash plate 410 can be selectively positioned in 
the same fashion. 
In the instance where the splash plate is selectively activated, it is 
possible to maintain a stationary reflector 101 with the splash plate 
providing the moving beam which is reflected from the stationary reflector 
to produce whatever pattern is desired. Conversely, the splash plate may 
be maintained stationary and the reflector can be selectively moved as 
described above. Of course, it is possible that both the splash plate and 
the reflector can be selectively moved in order to establish a complex 
beam pattern if so desired. 
The type of beam and pattern therefor is not a limiting factor in this 
invention. Rather, the beam and its configuration, as defined by the user, 
is determined by the number, size and positioning of the various 
electromagnetic devices. 
Thus, there is shown and described a new and unique radar system with an 
electromagnetic drive which selectively controls the position of the beam 
which is prepared and generated by the system. The system uses 
electromagnetic drives to control the positioning of the splash plate or 
reflector. However, only portions of the splash plate or reflector need be 
controlled at any time. With this arrangement, the heavy duty bearings, 
drive trains, and support structure of existing radar systems can be 
eliminated. 
It is to be understood that this description is directed to preferred 
embodiments. The number of electromagnetic drives, the type of materials, 
specific mountings and so forth are subject to modification and 
rearrangement. Those skilled in this art may conceive of modifications or 
arrangements which are not specifically shown herein. Any such 
modifications or arrangements which fall within the purview of this 
description are intended to be included therein as well even if not 
specifically stated. It is clear that this description is not intended to 
be limitative of the invention. Rather the scope of the invention is 
limited only by the claims appended hereto.