close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3029442

код для вставки
April 10, 1962
R. c. HANSEN
3,029,432
sçANNING ANTENNA
Filed June l5, 1958
5 Sheets-Sheet 2
PROAGTIN
END
ENRGYLAUNCHIG END “y
Frequncy
Sofource Shift Ener
Robert C'. Hansen,
/NvE/vron.
BY.
Naw
Arron/Ly,
April 1o, 1962
R. c. HANSEN
3,029,432
SCANNING ANTENNA
Filed June l5, 1958
5 Sheets-Sheet 3
ATTORNEY.
April 10, 1962
R. c. HANSEN
3,029,432
SCANNING ANTENNA
Filed June 13, 1958
5 Sheets-Sheet 4
Pfg.6.
Rober? C. Hansen,
/NvE/vrof?.
BY.
ATTORNEY.
April 10, 1962
R. c. HANSEN
3,029,432
scANNING ANTENNA
Filed June 13, 1958
_
‘
5 Sheeis-Sheet 5
ENRGYLAUNCHIG
MW
A TTUR/VE Y.
United States
Aarent Office
3,ll29,432
Patented Apr. 1o, lesaì
l
_
3,029,432
'
SCANNING ANTENNA
Robert C. Hansen, Los Angeles, Calif., assigner t0
Hughes Aircraft Company, Culver City, Calif., a cor
poration of Delaware
f
Filed June 13, 1958, Ser. No. 741,770
11 Claims. (Cl. 343-768)
2
’
.
extremely rugged antenna array for providing a beam of4
controlled direction.
Yet another object of this invention is to provide a‘
mechanically rigid but physically simple antenna for scan
ning in a given angle, said antenna providing an external
surface which has a minimum extension above a given
plane.
'
It is a further object of this invention to provide an
This invention relates to scanning antennas, and par
ticularly to antennas for providing a scanning beam about 10 electronic scanning antenna which can be ñush mounted
in a substantially planar surface but which can scan
a selected plane and a given axis in the plane.
The art of generating and controlling electromagnetic
wave energy so as to propagate a controlled beam into
through a useful angle in the plane of the surface with
a beam which Vmaintains its characteristics despite the
angle of scan.
`
space includes many movable and electrically control
Yet another object of this invention is to provide an
lable arrays. Devices currently in use usually either 15
antenna system for propagating a-lowl side lobe narrow
point a radiating _device in the desired direction of propa
azimuth beam with a cosecant-squared elevation pat
gation or combine the energy radiated from a plurality
tern over an acute angle from a surface which is sub
of individual elements into a single beam which can be
stantially flush with the azímuthal plane.
varied in direction by appropriate associated means.
These and other objects of this invention may be
The devices of the prior art, however, have not hereto 20
achieved, in accordance with one feature of this inven
fore combined the required physical characteristics and
tion, by an arrangement using a plurality of phase re
electrical characteristics in a satisfactory manner.
lated
radiating elements and an associated wave. trapping
For modern applications, such as mobile installations,
surface. The phase related radiating elements may com
it is not desirable to have a large movable antenna array
for controlling the direction of theï emitted beam. It is 25 prise a plurality of slot radiators arranged along an en-`
ergy launching line and fed yby equal lengths of waveguide
instead preferable and in many cases even necessary to
generate the desired lbeam with a structure which in
volves only a minimum of inertia. The arrangements of
the prior art which have avoided the use of mechanical
conductors arranged together to» form a sinuous feed.
Variation of the frequency applied to the sinuous feed
results in the radiation from the slot radiators'of a com
movement have almost uniformly -been bulky and rela 30 bined beam which is propagated normal to the line of the
radiators or at an oblique angle thereto, depending upon
tively fragile and have furthermore sulfered in degradation
the difference of the frequency from a center frequency.l
of beam characteristics with the! deviation of the direc
VAssociated with the line of the'radiators and in the same
tion of scan from a selected optimum direction.
plane may be a wave trapping surface having conductive,
ln many installations, for example, it is desirable to
generate a cosecant-squared elevation beam about an azi 35 discontinuities substantially parallel to the line of the>
radiators. Energy from the radiators may be directed
muthal plane, and to maintain the cosecant-squared ele
vation patternV as the beam is moved within a scanning
angle about a given axis in the azimuthal plane. Other
onto a launching portion of the wave trapping `surface
and confined along the length of the wave trapping sur
face with the result that energy is radiated into spacel
scanning patterns may of course be desired, but never
theless it has heretofore been impractical to maintain the 40 fron; the opposite end thereof. The angle made by the
beam with respect to the conductive dicontinuities may
desired beam shape, whatever beam is desired, for a large
enough scanning angle to be of practical value to a sys
tem. The devices heretofore available have therefore
become oblique, as the frequency is changed and theV
beam is caused to scan, without degradation of the beam
shape. Variation'and selection of the gap between dis
been even less suitable for specific applications in which
continuities, the depth of the discontinuities and the con
it is desired that the antenna provide an extremely low
figuration of the discontinuities proceeding along the wave
silhouette or be ñush mounted. It may be desired to scan
trapping surface may be used to insure the desired beam
in the forward direction of ymovement of an aircraft, for
pattern. An energy splash plate member may also be
example, but without appreciably'increasing the areo- `
employed to direct energy from the radiating elementsl
dynamic drag of the airplane. Such an "antenna installa
tion should not be confined by its nature to a particular 50 onto the launching portion of the wave trapping surface.
In accordance »with other features of the invention, the
location, such as to the limited locations at which it is
nature of the conductive discontinuities, the nature of the
possible to place a radome or other streamlining struc
wave trapping surface and the arrangement of the energy
ture. Heretofore it has been extremely difficult to pro
feed may be altered to derive particular advantageous
vide a directional/scanning antenna which can be mounted
features. For example, the entire surface may be made
substantially flush with a given surface and which can
completely flush with the 'planar surface in which the
scan without appreciable beam degradation through a
array is to be installed, by using a plurality of sinuous
considerable angle about a selected direction and in a
feeds having selected phase relations to generate abeam
given plane. The problems of constructing Isuch arrays
which is inclined onto the wave trapping surface.
become greatly complicated when it is further required
that the structure be mechanically rigid, that the surface 60 In accordance with another feature of tbe invention,
an arrangement may be provided which is particularly
be stable and strong, and that there be no critical toler
suited for lower frequency applications, such as in the
ances or critical operational characteristics.
UHF range. This arrangement may use a plurality of
Therefore an object of this invention is to provide an
dipole radiators mounted against a ground plane grid
improved scanning system for radiating a beam of de
sired characteristics through a given angle in a selected 65 and fed by a plurality of ganged variable phase Shifters
in the desired phase relation. Wave energy therefrom
plane.
^
may be trapped by a plurality of parallel rods spaced
Another object of this invention is to provide an an
apart from a ground plane and arranged in a selected con
tenna for scanning in a given plane, which antenna oper
figuration
to perform the desired wave trapping function.
ates substantially without inertia and` which provides a
scanning beam of controlled configurationî throughout a 70 The novel features of this` invention, as wellas the
invention itself, both as to its lorganization and method
considerable angle.
>
,
-V
of operatiom may best be understood when considered
>`_It is a further object of this invention to provide an j in
the light of the following description, when taken
3,029,432
3
guide sections 25 in alternating fashion, so that the en
in Connection with the accompanying drawing, in which
tire structure 25) forms a continuous sinuous waveguide
path for energy to be conducted. In the example shown,
the narrow walls 24 of the straight waveguide 22 lie in
the same planes and the broad walls 26 lie in parallel
planes. One terminal of the continuous sinuous feed
like reference numerals refer to like parts, and in whic :
FIG. 1 is a perspective View, partially broken away,
of an antenna arrangement employing a sinuous feed
and a corrugated metallic wave trapping device in ac
cordance with this invention;
FIG. 2 is a perspective view in simplified form of an
antenna 2t) may be taken as an input point or terminal
30 and the terminal at the opposite extremity may be re
garded as an output point or terminal 32 and coupled to
installation of an electronic scanning antenna, _such as
shown in FIG. 1, as flush mounted in the wing of an air
craft;
FIG. 3, comprising three diagrams of elevation beam
power vs. beam position for three different angles of
a load (not shown). Included, in the present example
10 of a scanning antenna 20, are a plurality of slot radiat
azimuth scan, and labeled FIGS. 3a, 3b and 3c respec
tively, shows the effective operation of a device con
structed in accordance with the invention;
FIG.l 4 is a simplified view showing a cosecant-squared
beam elevation pattern as provided by a device in ac
cordance with this invention;
FIG. 5 is an alternative arrangement of a device in
accordance with the invention, showing a different cor-
rugated surface arrangement than is illustrated in FIG. l;
FIG. 6 is a perspective view, partially broken away
and in simplified form, of another alternative arrange
ing apertures 40 centrally positioned along a common
energy launching line which is transverse to the straight
waveguide sections 22.
These slot radiators 46 are so
positioned, and the lengths of the linear waveguide por
tions 22 and the interconnecting waveguide portions 28
at the extremities are so selected, that equal path lengths
exist between successive apertures 40.
Such an arrange
ment is described more fully in a copending application
entitled “Frequency Sensitive Rapid Scanning Antenna,”
Serial No. 374,708, tiled August 17, 1953, by E. Strum~
wasser and L. C. Van Atta and assigned to the assignee
of the present invention. Reference may be made to the
copending application `for a detailed description of the
operation of this continuous waveguide antenna Ztl.
completely flush mounted in accordance with the inven 25 Briefly, however, the application of energy of diiferent
tion; and
frequencies to the input point 30 results in the provision
ment of an electronic scanning antenna which may be
FIG. 7 is a perspective simplified view, partially bro
ken away, of yet another alternative arrangement in ac~
cordance with this invention which is particularly suit
able for somewhat lower frequency ranges.
, In accordance withy the invention, referring now to
IFIG. 1„ there may be provided an electronic scanning an
tenna which generates a controlled beam in space over
of energy of different phase relation at the slot radi
ators 4t). The phase relation at the slot radiators varies
in a continuous uniform fashion with the frequency.
Thus the slot radiators 4u are fed in phase controlled
relation. The radiation emitted from the individual slots
40 combines into a single beam of selectively variable
direction dependent upon the frequency.
a scanning angle lying in an azimuthal plane. An azi
It should be noted that the interconnectingv sections
35
muthal planeE as the expression vis here used, is intended
28 at the ends of each of the straight waveguide sec
to refere4 to any reference plane and not merely to a
tions 22 may be either unitary, as shown, or comprised
horizontal plane. The antenna of the present invention
of separate members. The angular position or attitude
may be mounted in a vertical direction or at an angle,
and the term azimuthal is used merely to denote the
plane of reference which is most easily visualized. Simi
larly,- the fact that the scanning may be said to be donc
about a zero direction in the azìmuthal plane is again
merely employed for they purposes of description. In a
of the slot apertures/46 with respect to each other may
be varied in different manners in accordance with slot
radiation theory and practice. For example, the slots
at each end of the row of slots may be relatively paral
lel while the slots at the center may be at a marked an
gle to the row. Such variations, well understood by
those skilled in the art, are merely pointed out here for
direction is purely arbitrary, and may be at any angle 45 the purpose of making clear that the characteristics of
with respect to the axis of they present structure.
the beam provided may be varied in accordance with
The scanning antenna arrangement shown in FIG. l
the installation and the purposes which it is sought to
therefore may be considered to include a substantially
accomplish.
planar wave guiding surface 10 lying principally within
The scanning antenna or continuous waveguide ar
an azimuthal plane. The wave guiding surface is of the 50 rangement 25) thus provided provides a very simple means
surface irregularity type employing parallel linear con
for supplying a fan> beam. At a center frequency, the
ductive projections or “corrugations” to confine wave
beam
thus provided is directed in what may be regarded
energy. The corrugations in the wave trapping surface
as a zero. direction in a given plane. As the frequency
1_0 consists of landsV 12 and grooves 14 in the surface,
is changed, the direction of the beam axis shifts
the direction of the lands 12 being substantially parallel 55 applied
about
the
zero direction in the given plane. The scan
throughout the structure and substantially normal to the
ning antenna ZS shown in FIG. l would, by itself, gen
zero direction in the azimuthal plane. As shown, the
erate a beam narrow along the launching line and fan
corrugations defined by the lands y12 and grooves 14 may
shaped in a plane normal to the plane of the waveguides
be rectangular. The wave trapping surface 10 may be
22 and the energy launching line. With shifts in fre»
made of a metallic conductor, with the portion below
quency from a center value the fan-shaped beam would
given application what may be considered to be the zero
the grooved surface comprising the ground plane mem
ber 16 for the Wave trapping structure 10.
An electronically controllable directional antenna ar
retain its narrow width but wouid incline or scan down
on one side toward the plane of the waveguides 22.
The radiating apertures 40 in the continuous waveguide
ray 20 is mounted substantially parallel and below the
arrangement are placed along the launching line normal
azimuthal plane and the wave guiding surface 10 there 65 to the zeroy direction in the azimuthal plane. The com
in. Here again, the term below is used merely to desig
bined beam provided from the radiating apertures 4i)
nate a typical relationship for these elements and not to
define a limiting relationship. The structure may be
mayA thus be said to be a launching beam, to distinguish
the energy thus radiated from the energy which is directed
mounted upside down, for example, and the operation
into space, which is referred to below as space radiated
70 or space propagated energy. The corrugated wave trap~
will not be affected.
'
The directional scanning antenna 20 may be comprised
of a plurality of like rectangular straight waveguides 22
which are substantially parallel to each other. The ends
of successive adjacent pairs of these straight waveguides
22 are coupled together by interconnecting arcuate wave~
ping surface member lo, therefore, is hereafter referred
to as having a launching end portion, which is the por
tion adjacent the radiating apertures 4t), and a space
propagation end portion at the extremity thereof which
3,629,432
is 'furthest from the radiating apertures ‘40. S/een in plan
view, the space propagation end -may have a hemispherical
shape which is substantially symmetrical with the given
axis, which is the zero direction.
'
The corrugated surface wave guiding member 10 may
6
craft is not shown. With reference to FIGURE 2,> it may
be seen that the wave guiding structure 10 is substantially
flush mounted with the leading portion 62 of the aircraft
Wing 60 and that it canscan in the forward direction of
v the aircraft and at an angle to either side. .The same type
be physically mounted adjacent the continuous waveguide
of `an installation might of course be employed as scan
up or down or from a point mounted flush with the cabin
or vertical surface of the aircraft. The arrangement
shown in FIGS. 1 and 2 has further advantages, in that
arrangement 20 by dielectric spacers 42 which mechan
ically support and which may electrically separate the
corrugated surface member 10 from the continuous wave
guide arrangement Zi). A Wave energy splash plate 44, 10
the over-all silhouette is of small height. Consequently,
consisting of an elongated wave energy‘directing mem
the arrangement might be employed as part of a stream
ber having an angular or curved cross section, may be
lined housing protruding from a main structure. It is of
aiììxed along the launching line to divert the launching
significance that no outer protective structure need be
beam onto the launching Aend of the corrugated surface
wave lmember lil. The splash plate 44 need not have 15` employed with this arrangement, so that aberrations in
the beam do not result and extra physical assemblies are
a special configuration, as long as energy is diverted from
not
needed. it would of course be possible and in some
a direction substantially normal to the continuous wave
instances desirable to fill the grooves of the structure
guide arrangement Ztl _to a direction of substantial inclina
shown in FIG. l with a material such as ceramic or to
tion toward theazimuthal plane. A dielectric or other
closure _member ‘t6 which is substantially transparent to 20 cover the entire corrugated surface Siti with a material
which is transparent to electromagnetic wave. energy.
electromagnetic wave energy may be employed to close
The arrangement provided by this invention lmakes
the opening defined by the free ’end of the splash plate
feasible the controi of beam shape as well as electronic
control of the beam direction. For purposes of search~ .
ing an area in order to identify the position of other
member 44 and the surface of the corrugated wave guid
ing surface member i0. This Wave energy window 4d,
which may be of polystyrene or other suitably transmissive 25
objects it is usually preferable that a fan beam having
material, may be mounted at an angle of inclination with
what is known as csc2 i9 elevation distribution'be em~
ployed. Such a beam is considered as a fan beam and
respect to the azimuthal plane to provide a fairing or
streamlining surface for the mounting of the complete
is usually relatively narrow in azimuth. Disregarding the
antenna of this invention. A source of frequency shift
energy 50 is coupled to the input section of the con 30 side lobes usually present, which are relatively minor,
such a beam appears in elevation as is shown in FIG. 4.
tinuous waveguide arrangement 20. By the term source
The
cosecant-squared beam has a fairly regular lobe on
of frequency shift' energy it is intended to include energy
the positive side of its zero elevation' axis ( which is in the
sources which provide a continuous range of frequencies
azimuthal plane)V and has a sharp cutoiî on the lobel
or successive steps of frequencies over the desired range.
Either such source will result in a jbearn scanning `over 35 on the negative side of the azimuthal plane. For pur
poses of operating a system for detecting and monitoring
a given angle from the continuous waveguide arrangement.
A brief description of the operation of the arrange
ment of FIG. 1 will first be provided. The source of
the position of objects, it is extremely important that- the
regularity of this beam be maintained over an entire
scanning angle, as far as possible. The present invention
permits provision of this desirable beam shape, as is
shown in the charts of PEG. 3. These charts illustrate
the signal strength of the beam in elevation from the
azimuthal plane, which is taken as H0, for successive
angles of deviation from the zero direction. The scanning
angle from the zero direction, here called B is shown in
i Flo_*s in three positions, where B=o, 8°, and 15°. In
each case it may be observed that there is excellent power
in the direction of the beam, the desired rise in power on
frequency shift energy 50 may be operated over a given
range of frequencies with a continuous variation between
the limits of the frequencies employed. The energy thus
fed to the continuous waveguide arrangement 20 therefore
results in the provision of energy in phase controlled
relation to the individual radiation apertures 40 in the
continuous waveguide arrangement 20. The phase rela
tion between these individual radiation patterns is such
that a launching beam is formed which scans an angle on
each side of a direction normal to the azimuthal plane.
the positive side of the beam and the d_esired sharp drop
The splash plate 44, however, diverts this energy from
a beam substantially normal to the corrugated wave
Y in the lobe on the negative side of the beam.
trapping surface 10 to a beam having a planar front
which is sharply inclined toward the corrugated wave
trapping surface 10. in accordance with the operation
of a corrugated surface when energy is launched thereon,
the energy is confined from the launching beam into
g the plane of the corrugated surface 10 may be zero or
may be varied within limits on either side. The scanning
a surface wave transmitted along the length of the corru
gated surface member 10 in a direction across the lands
12 and grooves 14. Details of the manner in which the
energy isforrned into the surface wave are described in
more detail below. The surface wave is subsequently
launched from the space propagation end of the corru~
gated surface member 10 and is directed into space. The
direction of launching of the energy in space is dependent
upon the frequency applied to the continuous waveguide
arrangement 29. Arrows have been employed to indicate
some of the possible directions in whichf the beam may
be launched relative to the corrugated surface 10. The
'disposition of the corrugated surface antenna lib and
the continuous waveguide arrangement 20 operates to
provide a controlled fan beam of desirable pattern
whether or not the direction of the beam is normal with
respect to the lands 12 and grooves 14.
An antenna so constructed is suitable for mounting in
amobile installation, such as in an aircraft wing installa
tion 6i), as shown in FIG. 2. ` The remainder of the air~
The details
of arrangement of the surface and the corrugations by
which this is achieved, together with the other elements
of the combination, are described in greater detail below.
It should be recognized that the angle 00 with respect to
is still spoken of herein, however, as 'being in the azirnuthal
plane.
The art of employing a corrugated surface to control
the radiation from a beam in one direction only has been
known and investigated for a considerable period.' Ref
erence may be made, for example, to the teachings of
Cutler in Patent No. 2,659,817 issued November 17,
1953. As shown in this reference, various surfaces, such‘
ss
as square corrugations, triangular or round corrugations
and spaced septa may be employed to guide the electro
` magnetic waves transmitted across the surface.
Waves
which are guided in this manner have a surface velocity
which is less than the velocity of the waves infree space.
The waves have a longitudinal component of electric
field which is transverse to the corrugations across which
they travel. The spacing between the corrugations and
the depth of the corrugations determine the propagation
velocity for a wave which is normal to the corrugations.
It is also possible, however, by the use of this invention
is to employ these relationships so as to determine with
3,029,432
regularity over a substantial angle the surface velocity of
energy transmitted at an oblique angle to the corruga
tions. Further, however, the arrangement thus provided
makes possible variations in the corrugated surface which
permit adjustment of the gain provided by the antenna
and control of the shape of the beam which is propagated
into space. Consequently the energy radiated as a launch
of gain, as by varying the ratio of the surface wave
velocity to the free space velocity for the length of
antenna involved. Those skilled in the art have available
various analytical techniques by which maximum gain
may be achieved given the operating wavelength the
length of the corrugated surface and the other conditions
involved.
In practice greater gains are obtainable with longer
ing beam is converted into a space propagation pattern
surfaces. A typical antenna has a length of the corru
of selected configuration and having controlled charac
gated
surface member 1l) over which the surface wave
10
teristics over the scanning angle.
travels of approximately ten operating wavelengths for
As to the control of the surface wave velocity with
the median frequency employed. For this type of struc
respect to the free space velocity, it is known that the
ture, it is usually alsopreferable that the launching por
trapping can be increased and the speed slowed by increas
tion, such as the curved launching segment shown in
ing the groove depth and by increasing the number of
FIG. 5, should be of the order of two operating wave
corrugations per wavelength.
In one practical embodiment of this invention, the
corrugated surface member was constructed with a geom~
etry of d/}\=0.0953 and h/}\=0.0648, with d/À and h/À
being the gap width and the tooth depth respectively.
lengths.
A different arrangement, by which an entire structure
may be substantially ñush mounted, is shown in the ar
rangement of FIG. 6, to which reference is now made.
_in this arrangement, a plurality of continuous waveguide
Such a configuration may be used over the principal 20 arrangements 7G, 71, '72 are employed. Each of the first,
corrugated surface, although various modifications may
be made at the energy launching end and at the convex
, edged space propagation end.
Some of these modifications are illustrated by corn
parison of the structure of FIG. l. The teeth of the
second and third continuous waveguide arrangements 70,
71, 72 is related to the continuous waveguide arrange
ment 20 of FIG. l and provides a continuous sinuous
path in like manner. In the arrangement of FIG. 6,
however, the radiating apertures 74 are positioned in
surface wave structure of FIG. 5 may be, as shown, thin
the broad wall portions of the interconnecting terminal
plates or vanes 13 instead of the square corrugations of
sections. The radiating apertures ’74 lie in a plane de
FIG. 1. These vanes 1.3 may vary in height along the
fined by the ends of the continuous waveguide arrange
direction of travel of the surface wave, and the substan
ments 70, 71, 72. The radiating points which are thus
tially planar surface itl may be modified by arcuate por 30 defined lie in the azimuthal plane of the corruga ed sur
tionsl at either or both ends along the direction of wave
face member 10. The corrugated surface member 10
trapping. For example, as shown in FÍG. 5, the end
may include a cover plate 11 which extends across the
at which energy is launched onto the corrugated surface
ends of the continuous waveguide arrangements 70, 71,
member may be curved upwardly ( as viewed in FIG. 5)
72. The cover plate 11 is apertured to correspond to
from its launching edge to receive the energy provided in 35
the launching beam. Similarly, at the space propagation
end of the corrugated surface member 10, there may be
a downward curve which, alone or together with the
the radiatingr apertures ’74 and provides a flush surface.
Each of the continuous waveguide arrangements ‘70,
71, 72 of FIG. 6 lies in a plane substantially normal to
the azimuthal plane, the planes of these continuous wave
depth and spacings of the vanes 1.3, makes possible the
guide arrangements 70, ‘71, 72 being parallel and adja
:attainment of the desired beam shape and position (in 40 cent and the arrangements 76, 71, 72 providing coexten
the elevation direction) of the maximum of the beam.
sive and adjacent waveguide groupings. The apertures
With the approximate configuration shown the cosecant
74 positioned in the curved connecting sections of the
squared beam pattern may be achieved, or patterns of
continuous waveguide arrangements 7%, 71, 72 are in this
other desirable characteristics may be attained if desired.
instance mounted substantially parallel to the plane of
45
It is extremely important to note that with the types
the waveguide arrangements 70, 71, 72, so as to be re
of configurations shown in FIGS. l and 5 there is no
sponsive to the electric vector of the energy transmitted
significant degeneration of the beam shape when the
along the continuous waveguide arrangements 70, 71 or
beam is launched across the corrugated surface in a di
72. in accordance with known radiation pattern form
rection which is skewed or oblique to the direction of the
ing techniques, the radiation apertures 74 in each line
corrugations. It would appear upon first examination 50 may be placed along a central axis or spaced slightly to
that a beam launched at an angle across corrugations
either side of the central axis of each waveguide arrange~
would not be properly controlled as a surface wave, be
ment 70, ’71 or 72.
cause it is known that when a component of electric field
A single frequency shift source of energy 5|) may be
vector is parallel to corrugations there is no surface wave
employed with the plurality of continuous waveguide ar
55
effect. because no trapping can take place. Such degen
rangements 70, 71, 72. A first of the continuous wave
eration of the beam with a skewing relative to the cor
guide arrangements 70 may be coupled directly to the fre
rugations does not take place. The beam retains a
quency shift source `of energy. The succeeding second
substantially cosecant-squared pattern despite displace
and third continuous waveguide arrangements 71 and 72
ment from the selected direction. It is assumed that
may, however, be coupled to the frequency shift source
control of the surface wave is maintained because of the 60 of energy 50 through individual first and second phase
manner in which the energy is launched and maintained in
shifter devices 76 and 78 which provide successively in
a planar front. because the wave trapping is not operated
creasing amounts of phase `shift to the energy from the
in a critical mode, and because the component of the
frequency shift source of energy 50.
electric vector which is normal to the corrugations exerts
With the amount of phase shift provided from each
a great influence on trapping, and thus on the velocity 65 of the phase shifters 76 and 78 being properly selected
of the surface wave. There is, for this hybrid surface
with respect to each other, in accordance with well
wave, no electric vector component which is parallel
known techniques, the radiation patterns provided from
to the corrugations. Therefore the surface wave velocity
the continuous waveguide arrangements 70, 71, 72 unite
changes only slightly despite displacement of the com
into a single beam which is inclined with respect to the
70
bined beam from the zero direction.
azimuthal plane. The operation of the :arrangement of
Antennas such as are provided in FIGS. 1 and 5 can
FIG. 6 may thus be understood as involving an azimuthal
be modified in other ways than by curving or tapering
scanning following inclination of the beam into the
the corrugated surface member to control the beam pat
launching portion of the wave trapping surface 10. The
tern. A wave trapping surface can in addition be ad
azimuthal scanning in the :arrangement of FIG. 6 is
ìusted to selected conditions, to achieve desirable amounts 75
9
3,029,432'
achieved in a manner similar to the arrangement of FIG.
1. "Ihat is, as the frequency of the applied energy is
changed, the phase Yrelation of the radiation from the
apertures 74 in each continuous‘waveguide arrangement
70, 71 or 72 is likewise changed to provide a combined
fan beam which would scan in the plane of the wave
guide arrangements ,70, 71, '72 normal to the azimuthal
10
shaped peripheral configuration, in conjunction with a
parallel plate transmission line arrangement and a par
allel of probes. As the shaped surface of the corrugated
drum is rotated adjacent the transmission line plate and
the probes, energy of a variable selected phase relation is
provided to each of the probes. A fuller understanding
of the operation of such a phase shifter may be appre
plane. The presence of the iirst and second phase Shifters
ciated by reference to the above copending application.
'76 and 78 between second and third continuous wave
The wave trapping surface 10 in the arrangement of
guide arrangements 71 and 72, however, alters the direc 10
FIG. 7 is provided by a plurality of coplanar substantially
tion of the single resulting beam so that the single result
parallel linear conductive elements or rods 96, separated
ing beam is inclined in the direction of the corrugated
by dielectric or other insulative spacers 92 from a Second
surface member 10 and is trapped thereby. The angle
ground plane surface 94 made up of a plurality of wires
of inclination of the single resulting beam can be modified
or other conductors arranged like the first ground plane
with respect to the azimuthal plane, within limits, but
member 82. 'I‘he term “corrugated surface member” as
will be sufficient to cause the wave trapping to occur. If
used here is intended to include such an arrangement of
needed, Vgreater tooth depth and gap spacing can be em
linear elements 90 separated from a conductive ground
ployed to assure greater wave trapping.
plane 94. The `pacing between the linear Árods 90' or
Once the surface wave has been created in the cor
rugated surface member 10, the resultant beam scanning 20 wires in the azimuthal plane in which they are principally
located, and the separation of the linear rods 90 from the
pattern, varying about a zero direction in the azimuthal
ground plane, determine the extent of the wave trapping
plane, is achieved in the manner described in conjunction
and the surface velocity of the waves, as in the arrange
with the description of the operation of FIG. 1.
ment of FIG. l. The rods 90 may also be separated from
The arrangement of FIG. 6 will be appreciated as
having particular adaptability to flush mounted installa 25 the second ground plane 94 by conducting wires (not
shown); this construction would be a corrugated surface
tions. The entire corrugated surface 10 and the radiat
ing’apertures 74 may be ñlled, if desired, with a low
Y made of rods and wires.
The arrangement of FIG. 7, which is particularly suit`
able for operation in the ultra high frequency range and
in relatively fixed installation, operates as follows. Energy
loss dielectric material, such as a Aceramic (not shown).
Whether or not such a technique is employed, however, a
Y ‘scanning antenna having excellent beam pattern charac
of a single frequency provided from the source of fixed
frequency energy 84 to the phase Shifters S6, is provided
thereby to the individual dipole radiators 80. Simultane
ously, the ganged phase shifter devices 86 are varied in
teristics is provided which is structurally extremely strong
and simple to fabricate. Furthermore the rigidity of the
device and its independence of operating characteristics
insures reliable satisfactory operation under adverse con
ditions of placement and use.
An arrangement which is particularly suited for fre
quencies of operation somewhat lower than the applica
tions which the above described arrangements might be
employed, such as in the ultra high frequency range, is
a predetermined manner by the actuatingmeans 88 to
35 cause energy to be fed in the desired phase relations to
the dipole radiators Si). Co 1sequently, there is provided
a launching beam which varies about a zero direction in
the azimuthal plane and swings to a maximum on each
shown in FIG. 7. Referring to FIG. 7, the arrangement 40 side of the zero direction, as the variable phase‘shift
devices S6 are changed through a cycle of operation.
there provided includes a plurality `of radiating elements,
'I'he
principal axis of the launching beam from the dipole
such as dipole radiators 80, mounted along an energy
radiators 89 has here been selected to lie in the azimuthal
launching line. The dipole radiators 80 are mounted
plane. Consequently, the launching beam »is trapped by
against a first ground plane member 82 which may be
comprised of a metallic plate but which preferably, as 45 the wave trapping surface 10, transmitted along the WaveV
trapping surface 10 as a surface wave and propagated
shown in FIG. 7, consists of a grid of conductive Wires.
into space from the space propagation end which is
Such a grid 82 may be effectively employed for a ground
spaced apart from the dipole radiators 80. As with the
plane provided that the spacing between parallel wires
arrangements of FIGS. 1, 5 and 6, the control is main-ï
is less than one fourth of the operating Wave lengths em
tained
over the beam through an angle as great as 45°.
ployed. In this arrangement, each of the dipole radiators 50
Thus the beam has substantially like characteristics
Sti may be fed, as by a coaxial line (shown only schemati
through such an angle despite its Obliquity »to the wave
cally), with energy of a diñerent phase. The desired
trapping surface 10.
phase control relation is achieved in the illustrative ex
As with the antennnas of FIGS. 1 and 5 the eleva
ample of FIG. 7 by coupling energy from a source of
energy of fixed frequency ‘84 to each of the dipole radia 55 tion pattern may be controlled and enhanced by varying
the rod of wire diameter, spacing and height above
tors 8@ through a different variable phase shifting device
ground plane, especially at the two ends.
86. The phase relation of energy provided to the dipole
Thus there has been provided a scanning antenna
radiators 4Si) may be changed, and the beam provided
arrangement which generates a contorlled beam through
caused to scan, `by employing a ganged cyclically operat
ing arrangement for driving the variable phase Shifters 60 a scanning angle in a given plane. The arrangement
may be utilized to control the radiation pattern provided,
86. In the present arrangement the variable phase Shifters
to provide superior physical configurations and to achieve
v36 are, as shown in simplified form, coupled together
reliable and stable operation.
and driven together from a mechanical actuating means
I claim:
83. The rotation of a drive shaft, for example, by the
actuating means 88 may be used to provide the ganged 65
1. An antenna comprising: a plurality of radiators dis
posed along a launching line and fed in phase controlled
Shifters are available in the art, and although a number
relation whereby a well defined beam will be radiated
of mechanical or electrical means will suggest themselves
in a predetermined direction, means for varying said
for providing phase shifts in a selected pattern, a par
phase relation for Varying said direction of said beam
ticularly suitable arrangement is provided in an applica 70 throughout a given scanning angle, and means including a
tion entitled Mechanical Phase Shifter, Serial No.
wave trapping surface having conductive discontinuities
529,557, now Patent No. 2,836,821, ñled August 19,
disposed substantially parallel to the launching line and
1955, by R. S. Elliott and K. C. Kelly, and assigned to the
arranged to trap electromagnetic wave energy in said
assignee of the present invention. The invention there
beam from said radiators, said Wave trapping surface
described employs a corrugated rotatable drum having a 75 lying principally in a given plane and radiating into space
cyclical operation. Although a number of variable phase
spaanse
li
a controlled pattern of energy throughout said scanning
angle lying substantially within said plane.
2. A scanning antenna for radiating a beam within a
scanning angle which lies substantially symetrically about
a given axis and in an azimuthal plane and comprising:
a plurality of radiating elements lying adjacent said azi
muthal plane along a second axis substantially normal to
Said Agiven axis, said radiating elements being disposed
substantially symmetrically with respect to said given
axis; means coupled to each of said radiating elements
for providing energy thereto whereby said elements will
radiate a well defined beam of electromagnetic energy,
and a plurality of spaced conductive elements lying prin
cipally along said azimuthal plane and substantially paral
lel to said second axis so as to form a surface wave trap
ping structure, said surface wave trapping structure being
substantially symmetrical with said given axis and posi
tioned to convert the radiation pattern from said radiating
elements into a space propagation pattern of selected con
continuity in said irregularities
l whereby the energy in said
beam will be radiated into space in a predetermined pat
tern having a direction determined by the direction of
said beam.
6. An antenna comprising a waveguiding surface hav
ing a plurality of substantially parallel conductive irregu
larities, at least one waveguide path having a plurality of
radiating apertures therein disposed in a line substan
tially parallel to said irregularities for radiating a Well de
fined beam of electromagnetic energy onto and across said
guiding surface, means for controlling the phase of the
excitation of said apertures for controlling the direction
of said beam throughout a scanning angle, said waveguid
ing surface lying principally in a given plane and includ
ing a launching portion for radiating into space a con
trolled pattern of the energy in said beam, the direction
of said pattern being controlled by the direction of said
earn within said scanning angle.
7. An antenna comprising a waveguiding surface hav
ing a plurality of substantially parallel conductive irregu
figuration, control means effective to cause said beam to 20 larities disposed generally in a plane so as to form an
sweep across said structure to thereby vary the direction
input section and a launching section, at least one sinuous
of said propagation pattern in said azimuthal plane.
3. A scanning antenna comprising: means including a
waveguide path having a plurality of radiating apertures
therein disposed in a line substantially parallel to said
irregularities for radiating a beam of electromagnetic en
for providing an energy launching array; i eans coupled
ergy, means for directiing said beam onto said input
to said radiating elements for providing energy of se
section of said surfaceV whereby said beam of energy will
lected phase relation to the individual radiating elements
be guided across said surface, means for controlling the
of a predetermined phase relation whereby a beam of
phase excitation of said apertures for controlling the direc
energy will be radiated from said elements, means for
tion of said beam throughout a scanning angle whereby
varying said phase relation whereby said beam will scan 30 said beam will sweep across said surface within said angle,
through a given angle, and a wave trapping device of the
said launching section including discontinuities in said ir
surface irregularity type having spaced members lying
regularities whereby said energy will be radiated into space
in lines parallel to said given axis, said spaced members
in a controlled pattern having a direction determined by
lying principally along an azimuthal plane and having
the direction of said beam.
selected relationships to convert the launching beam into
8. An antenna comprising a waveguiding surface hav
a space radiation pattern having controlled characteristics
ing
a plurality of substantially parallel conductive irregu
for each- position of said beam within said scanning
larities that are arranged substantially in a plane to guide
angle lying within said azimuthal plane.
electromagnetic energy thereacross, a plurality of groups
4'. An electronic scanning antenna having a small di
plurality of radiating elements spaced along a given axis
of waveguides having radiating apertures disposed sub
mension in an elevation direction above an azimuthal 40 stantially in said plane for radiating electromagnetic en
plane, said antenna scanning about a selected direction
in said azimuthal plane with a substantially cosecant
squared elevation beam, said antenna comprising: a
plurality of radiating elements disposed in a plane paral
lel to said azimuthal plane and substantially normal to
said selected direction; energy feeding means coupled to
said radiating elements and feeding said radiating >ele
ments individually with energy of selected phase rela
tion, such that the combined radiation pattern from said
radiating elements is a launching beam which varies in
direction about said selected direction as said phase rela
ergy therefrom, the apertures in a given group being dis
posed in a line substantially normal to said irregularities
and excited to direct the energy therefrom into said plane,
the relative phases of the radiated energies from said
groups forming a resultant beam of electromagnetic en
ergy that is propagated into said plane and along said sur
face, said waveguiding surface lying principally in said
plane and radiating into space a controlled pattern having
a direction determined by the direction of said beam.
9. An antenna comprising a waveguiding surface hav
ground plane portion and conductive surface disconti
ing a plurality of substantially parallel conductive irregu
larities disposed to form a substantially plane input sec
nuities disposed in parallel lines normal to said selected
direction and lying principally in said azimuthal plane,
waveguides having radiating apertures disposed substan
tion is changed; and a wave trapping member having a
tion and a launching section, a plurality of groups of
said wave trapping member including a launching end
tially in said plane for radiating electromagnetic energy
larities that are arranged to form an input section and a
a direction determined by the direction of said beam.
10. An antenna comprising a waveguiding surface hav
therefrom, the apertures in a given group being disposed
adjacent to said radiating elements for trapping beam
in a line substantially normal to said irregularities and
energy radiated therefrom, said discontinuities being varied
excited to direct energy therefrom onto said input sec
with respect to each other and said ground plane por
tion along the selected direction from the launching end 60 tion whereby said energy will be guided by said irregu
larities, the radiated energies from said groups having re
to confine energy emitted from said radiaing elements
lated phases for forming a resultant beam of electromag
into a substantially cosecant-squared beam despite dis
netic energy that is guided along said input section to said
placement of the beam from the selected direction in the
launching section, said launching section including at least
azimuthal plane.
one discontinuity in said irregularities whereby said energy
5. An antenna comprising a waveguiding surface hav
will be radiated into space in a controlled pattern having
ing a plurality of substantially parallel conductive irregu
launching section, radiating element means disposed adja
ing a plurality of substantially parallel conductive irregu
cent said waveguiding surface for radiating a well defined
beam of electromagnetic energy onto said input section 70 larities arranged substantially in a plane to guide elec
tromagnetic energy thereacross, a plurality of dipole ra
so that said beam will be guided across said surface, means
diators arranged to form an array disposed along a launch
operatively interconnected with said radiating means for
ing
line substantially parallel to said irregularities, means
varying the direction of said beam throughout a given
for feeding said dipole radiators in phase controlled rela
scanning angle whereby said beam will sweep across said
tion whereby a well defined beam will be radiated onto
surface, said launching section including at least one dis
3,029,432
.
13
,
said guiding surface in a predetermined direction, means
for varying said phase relation for varying said direction
of said beam throughout a given scanning angle whereby
14,
relation for varying said direction of said beam through
out a given scanning angle whereby said beam will sweep
' across said guiding surface, said launching portion includ
waveguiding surface lying principally in said plane and 5 ing at least one discontinuity in said irregularities and be
ing effective to propagate into space a controlled pattern
including a launching portion effective to propagate into
of energy having a direction determined by the direction
space a controlled pattern of energy having a direction
of said beam.
saidY lbeam will sweep across said guiding surface, said
determined by the direction of said beam.
1L An antenna comprising a waveguiding surface hav
ing a plurality Yof substantially parallel conductive irregu
larities arranged torform a substantially plane input sec
tion and a launching section which are effective to guide
» electromagnetic energy thereacross, a plurality of dipole
radiators arranged to form an array adjacent said input
References Cited in the lile of this patent `
UNITED STATES PATENTS»
2,411,032r
Gluyas et a1. ___’_____ __ Nov; 12, 1946
2,418,124
Kandoian ____ _»_ ______ _.. Apr. l, 1947
2,624,003
section and arranged along a launching line substantially 15 2,659,817
parallel to said irregularities, means for feeding said di
2,676,257
pole radiators in phase controlled relation whereby a well
defined beam will be radiated onto said input section in a
predetermined direction, means for varying said phase
983,033
Iams ___-; __________ __ Dec. 30, 1952
' Cutler ______________ __ Nov. 17, 1953
Hebenstreit ___-,___’.____ Apr. 20, 1954
FOREIGN PATENTS
France ...___f _________ __ Feb. 7, 1951
Документ
Категория
Без категории
Просмотров
0
Размер файла
1 572 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа