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Патент USA US2411872

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Dec. 3, 1946.v
c. B. HLFELDMAN ETAL
MICROWAVE DIRECTIVE ANTENNA
2,411,872
v
' Filed June 11, 1942
PIPE 20
`
ATTUÃ’NEY
Patented Dec. 3, 1946
" 2,411,812 A
_GFI-*ICE
* UNITED, STATE s PATENT
annahm
MICROWAVE DIRECTIVE ANTENNA
„
>
4
George E. -v
can n. 1r. Feidman, Rumson, N. J., andassignors to
Mueller, Jackson Heights, Nr Y.,._
- Bell Telephone Laboratories, Incorporated, New
' York, N. Y., a corporation of New' York
Application June 11,1912, semi Np. 445,532 ' _
l
and therefore a given phase velocity at the oper
This invention relates to antennaarrays and
V more particularly to microwave _end-on antenna ‘
`arrays.
'
’
» As is known,'in the microwave or centimetric"
ating frequency. and a'given length. Each of
’ the remaining vguides has a b width and a phase
’ _ velocity dependent upon its physical length, and
' field open-ended metallic _ air-filled guides and
horn antennas, and broadside arrays comprising>
simple pipe antenna units or horn units, have
a phase length o_r'over-all phase vangle'shiit de-_
pendent‘upon its b width and physical length
In tliegcase of transmission, theenergy o_r wave- .
been suggested for emitting and collecting radio » .let-emitted by each vof the remaining guides and
propagated in the desired end-on direction, and
f energy. Also, leaky air-filled pipe antennas o_f
the longitudinal or transverse slot type have been 10 thelwavelet emitted by the shortest guide and
-having a similar propagation direction are in
suggested for securing broadside, oblique and
phase'agreement and combine to produce an
end-on radiation. While, iny general, the above
additive eifect along the axis ofthe system.
arrangements have been- used with- success for
Consequently. the wavelets from all end-on pipe
broadside and oblique radio action, they have not
combine to produce an extremely sharp,
15
functioned in an entirely satisfactory mannerfor '_ radiatorsl
nxed',1 end-on maximum lobe analogous to the
securing lpure end-on action. Since for certain
“comb” antenna lobe 39 or“ illustrated in Fig.
purposes as, for example, for‘use in a scanning
5 of Patent `2,236,393, H. 'Il'. Friis and A. _C. Beck,
or radar single unit antenna system or in a multi
unit steerable array of the broadside MUSA type, ` granted March 25. 1941. Conversely, when used
for receiving; the differently phased wavelets ab-A
end-on units- or subarrays are advantageous, -it
sorbed at the two above-mentioned pipe aper
now appears desirableto securev a highly efdcient
'end-on unit or a ysub-array of end-on unit an
tennas; A broadside antenna, an end-_on an
tenna and an oblique antenna are here denned'
as antennas in which' the angles between the
tures and having the aforementioned errl-on di- "
rection have a cophasal relation at the .receiverI
by reasonA of the difference in phase velocity and
phase length ofthe two guides. While, as dis
maximum direction of radio action and the an
tenna axis are substantially 90 degrees, 0 degreesy y
closed in the ll?roceedin_gs of their. R. E., Decem- '
and acute, respectively.
tangular pipe radiators orcollectors. the inven-' j
It is one object 'of this invention to cuminl f
on antenna radio action.v
Itis another object of this invention to obtain`
v ~ .highly directive end
anend-on 'microwave array comprising a plural- , ~
ity of end-on elemental or unit antennas.
_
i J
ber 193 ,ipages 1500 and 1501, various types» of guided _ ave components'may be used -with rec
tion will be explained‘in` connection with-the
'which component is' polarized parallel to' th
transverse electric component- of the Haiiwave,
. small transverse guide ldimension a.
The ‘invention wm be more muy understood
It is still another object of this invention to' y ' from
a 'perusal of the following speciilcation
secure a small compact subarray ofend-on units.
suitable for use as a broadside MUSAv unit. ‘
According to one embodiment of .the invention,
a plurality as, for example, twenty, of air-filled
~-open-ended metallic rectangular wave guides or
ï taken in conjunctiony with the drawing on which
' _ like reference characters _denote elements of sim-_ A
ilar function and on which:
. -
_
'Figs' L1, 2`and 3 are side,_ end andtopviews.
pipes are positioned parallel to each .other and 40 respectively, of a simple embodiment of thej in_
aligned with the path of desired end-on radiation
.-Figs. 4 and 'É are perspective and end views,A
or reception. As used herein the term "rectan- _
respectively,
of ya 'preferred embodiment of they.
gular” denotes a quadrangular figure other than
square, and the term “quadrangular” includes . invention; and
Fiss. 6 and 'I are measured directive charac» I
-rectangular and square. _ The guides-have _equal
.
teristics
:of the embodiment illustrated by Figs.
a or narrow transverse widths and graded physi
4 and 5.
cal lengths differing a given amount as, for exam
-Referring to Figsrl, 2 and 3,` reference nuf
ple, one-half wave~length, so that vthe remote
meral l designates a transceiver (TR) .which is ‘I
vention;
_
'
l
vopen ends or apertures are uniformly spaced in
the direction of desired radio action. The ex 50 connected by/the main air-ñlled guide or dielec- »
tric channel 2 and coupling guide section Ito an
-tremities or terminals are connected directly to
end-on array 4 constructed in accordance with
a- common dielectric channel and the associated
translation device, which may be va transmitter
‘ or_ receiver, or to a scanning transceiver unit.
The shortest _guide has a. given wide or b width,
the invention. The l.transceiver device isof v'the
type conventionally used infradlo scanning sys
v:ses y temsI and includes a pulse transmitten‘cathode- _
_
,
.
_
_
.
3
2,411,872
al
ray indicator, receiver and a circuit for alter
nately connecting the transmitter and receiver to
the main guide 2. If desired, an ordinary trans
_ `ity vn and therefore the dimension bn of pipe n
lation device,`such as a transmitter or receiver,
may be used in place of the transceiver 2. Array
4 comprises a rectangular air-filled metallic guide
tn which-renders, in the case of transmission.` the
wavelets or out-of-phase energies propagated
or pipe 5, hereinafter designated pipe o, and an- „
other rectangular air-filled metallic pipe 6, here
inafter designated pipe n, the far ends 1 of the
pipes o and n being open-ended and constituting
aperture-type elemental antennas and the near
ends 8 being immediately adjacent to each other
and directly coupled to the coupling section 3.
The longitudinal paths included in guides 2 and.
3 and extending between the device I and the.
near ends 8 are equal in electrical length. Pipes
o and n are positioned parallel to each other and
their longitudinal axes are aligned with the de
sired end-on direction or path 9' of radio action.
Pipe o has a given wide transverse dimension bo
are selected so as to obtain for pipe n a phase time
from the apertures 'l to the desired wave front
_ plane i I, which is perpendicular to direction 9, in
phase agreement at plane Il. Conversely, the
out-of-phase energies absorbed at apertures l.
from a wave having its front in plane I I arrive in
phase agreement at device I. The method of as-=
certaining the values for the phase velocity an,
the width bn and the phase time tn (=d/n/v») of
pipe n will now be explained.
A careful.distinctionshould be made between
vo, the velocity of phase propagation or the phase
velocity, which is an apparent rather than an
actual velocity, andthe actual velocity of e’nergy
propagation of the wave Within the air-ñlied
guide. As explained in the two articles “Rectan
and therefore at the operating frequency a given
phase velocity vo. Also, it has a given physical
length do and therefore a given “phase time”
to=do/vo. Pipe n has a given physical length du
greater by a predetermined amount KA than do,
as explained more fully below, where x is the 0p
erating wave-length measured in free space and
gular hollow pipe radiators” by W. L. Barrow and
F, M. Greene and “Waves in hollow tubes of rec
tangular cross section’î by L. J. Chu and W. L.
Barrow, both published in the Proceedings of the
I. R. E., December 1938, the phase velocity in an
air-filled rectangular guide and the propagation
velocity depend upon'the ratio of the operating
frequency to the guide cut-01T frequency, the
K is constant. Also, pipe n has a wide transverse
dimension bn which, as also explained below, may
width b and the dielectric constant of the mate
or may not differ from bo. The narrow transverse 30 rial constituting the channel.
See especially
pages 1532 and 1540, I. R. E. Proceedings, Decem
ber 1938, and seealso Patent 2,106,768, G. C.
l a dimensions of the pipes o and n are- equal.
Since, as stated above and as shown by arrow I0,
the transverse electric component utilized is par-.
allel to the short pipe wall or side, the dimension
a is the electric plane dimension. dimension b be
Southworth, February 1, 1938; “Wireless Engi
ing the >transverse magnetic plane dimension.
theory” vby IS. A. Scheikunoiï- et al., and “Hyper
neering," March 1942, page 93 and two articles
“Hyper-frequency wave guides-_mathematical
` In operation, assuming the array 4 is used for
'frequency Wave guides-general considerations"
transmitting, energy is supplied by device I to the "
by G. C. Southworth, both published in the Bell
connecting waveguide 2 and through coupling ‘
System Technical Journal, April 1936. As the b ‘
wave guide 3 to the input or near-end terminals 40 width approaches the _cut-oil? dimension, the op..
8 of pipe o and pipe n. The wavèlets entering
erating frequency being constant, the propaga
pipes o and n have the same polarity and phase
tion velocity becomes' a fraction of the free space
angle since the paths connecting the input aper-r
propagation velocity while the phase velocity be
comes a multiple of_ the free space propagation
velocity. In an air-filled guide the phase velocity
is always greater than the free space velocity.'
Hence, while the two guides may have the same
physical length, their phase lengths may be dii'
ferent, depending upon the relation of their> b
` tures to device I are'equal in length. yAs radiated,
the wavelets differ in phase angle an amount
corresponding to the physical separation between
the apertures 1 and dependent ’upon theb dimen
sion of pipe n. More accurately, the phase angle
of the wavelet emitted by aperture 'l of tube n
is retarded relative to that emanating from aper 50 dimensions and the phase velocities.
ture 'l of tube o by an amount t corresponding to
In order to secure phase agreement between
the time interval in which the wavelet from pipe _ the wavelets emitted at the apertures ‘I of~ the
o travels in the ether medium alöng path 9 to a
two pipes o and n, the spacing K). between aper
'point opposite aperture Tof pipe n, whereby the
tures being a constant, the phase time tn of pipe
wavelets are propagated in direction 9 in phase 55 n. must have the value given by the following
agreement and “in other directions in phase dis
equation :
y agreemena'and maximum radiation occurs end
Tvhe terms “phase agreement”_ and “co-_
phasal”, as used herein signify that the energies
have the same phaseA angle values and similar in
stantaneous polarities or have angles diiïering by
on.
60
where
dn=the given physical length of pipe n
360 degrees or a multiple thereof and similar po--
c=the free space velocity I
larities. Conversely, when used for the'collection
A7\=the operating wave-length as measured in air l'
of energy, the wavelets incoming ~in a direction -
N :an integer having a value such that the waves
from pipe o. and pipe n add in the same manner
opposite to directionl 9 have at any given instance 65
' a phase angle difference related-to the spacing
K)\,1and by reason of'the phase velocity charac
teristics and phase lengths of pipes o and n these
wavelets have, upon arrival at the transceiver l,
_ a cophasal relation whereby maximum .reception c"
occurs end-on. As explained below in connec
tion with Figs: 4 and 5, additional pipe radiators
may be employed to enhance the end-on action.
lConsidering the operation ofy the array 4 from
a mathematical standpoint, 'if bo, do, vo,-to and d» 75
'
as if the velocity in pipe n has any one -of a
number of values which make the >phase time
correct to within any number of complete
periods
'
}
K=a constant as, for example, 1/2 representing
in the two element system of Fig. 1 the spacing
between apertures.\ In a system~ comprising
more than two elements, K represents the uni
form spacing between adjacent apertures. and
nK the separation between the apertures of
'2,411,872 .
pipes o and n.
_
-
=1,_
For -the- two-element system
ì
Hence we have the general case
'
'
t* ...a
:10+ n_n
c i ri
`c
6
9 and in the case oi.' receiving maximum reception
occurs in a direction opposite to that represented
by arrow 9. In a system actually constructed in
accordance with Figs. 4 and 5 highly efñcient end
A on action was obtained.
l below.
Equation 2 equates the phase time for pipe n
_
with the phase time for pipe o -to which has been ^
added the phase time of the spacing. The `phase 10
\ time for pipe n, in terms of its own velocity is:
_
tnrdo-i-vnK).
y
The dimensions of the
system actually constructed are given in .the table
-(2)
Pipe
»
Pila-)N°- _ v
’
length
do
(a) :
8
_ and by substituting in vEquation 2 the value of
Multiplying both sides of Equation 5 by _c we have l
iN.
c
1
2
width in
cm.
0
bo 5. 6580
di
1.5
3/2
0
v bi 0. 5740
da
_ da
2. 0
2. 5
' 4
5/2
-1
-1
b2 5. 0006
b» s. 3463
3. 0
d4
tn as given by Equation _3 we get
Pipe b
'L2
d in A
2
-1
b4 5- 6580
d5
3. 5
7/4
-1
. bs 5. 9708
ds
d?
du
du
d10
du
du.
dia
du
.4. 0
4. 5
5. 0
5. 5
6. 0
6. 5
7.0
7. 5
8. 0
8/5
3/2
2
/ß
12/7
/8
14/9
3/2
16/9
-1
,-1
-2
-2
-2
-2
-2
-2
-3
‘ dia
8. 5
, 17/10
-3
bis 6. 0592
die
d11
dis
du
9.0
9. 5
10. 0
10. 5
18/11
19/12
20/13
3/2
-3
-3
-3
-3
bie
bi1
013
bis
22/13
_4 .
bzo 6.0738
d20 11
be
b1
bl
be
bm
bil
b
bis
bu
«
6. 2770
ß. 5740
5. 0580
5. 8463
0. 0328
6. 2155
G. 3970
6. 5740
5. 9265
6. 1904
6. 3200
6. 4479
6. 5740
In the system tested
From theïhteaching lon page 1532, Proceedings
y K was chosen tp be .1/2;`
30 do was chosen to be one wave-length, that is, X,
and the velocity 11o in pipe o was chosen to`be
2c. Substituting these values in (7) gives
1L
35
_ agli@
cî'l
n
frei@
-If the arbitrary constant N were not utilized and
if 'n were regarded zero we would have for pipe
40
n-_-10 a value _of
`
'
@15:
which would make bn>x and this would permit
45 higher order waves. In the above table the minus
valuesof :tN are used to keep bn within the
`
i
Referring now to Figs. 4 and,5, the array 40,-> limits.
Figs. 6 and 7 illustrate, respectively, the meas
hereinafter denoted “organ pipe array” comprises
twenty-one air-filled metallic rectangular pipes
4| designated 'for convenience, 0, I, 2 . . . 20 as
ured a. or` electric plane and the b or magnetic
50 plane characteristics of the end-on array actu
indicated bythe subscripts for lthe b dimensions.
The near end apertures 42 of pipes 4I are adja- .
ally constructed and having dimensionsvas given
vin the above table.Í As shown bythese curves, ,
the maximum electric plane lobe 44and the max
cent each other and directly >connected to the
imum magnetic plane vlobe 451are aligned sub- coupling section 3.l The twenty-one pipes are
aligned with the desired direction 9 of radio action 55 stantially with the axis 46 and the desired direc
»A tion 9, the angle “zero degrees” being coincident
and have uniformly graded lengths do, di,
with axis 46. More accurately, vin the magnetic
da . . . dao, as shown in Fig. 4, so that the spacing
plane, the principal axis 4of lobe 45 is exactly
between thefar end apertures 43 of ~each pair
aligned with the zero'degree direction but in the
of adjacent pipes isKA, and the spacing between
electric plane the largest axis of lobe 44 is at a
the aperture 43 of pipe o and aperture l43 of
slight angle to the zero degree direction„ the
any other pipe is nKA, where- n corresponds to
slight deviation resulting, it is believed, from the
the pipe designation. The a or electric plane
Also, as
widths are the same for all pipes. The bo, b1, \ coupling between the apertures 43.
_shown by the` curves of Figs. 6 and 7, the maxi
. bzo‘or magnetic plane- widths vary as
shown in the enlarged end-view, Fig. 5, since the 65 mum lobe in both planes has a relatively narrow
width and negligible secondary lobes 41.
_
b Widths of pipes 0, I, 2 . . . 20 are critically di
Although'the
invention
hasbeen
explained-in
mensioned as explained above in connection with
connection with speciiic embodiments, it is-not
-. Figs. 1, 2 and 3. The b _width variations are-notto be limited to the structures illustratedegsince
shown >in Fig. 4 inasmuch as the scalel employed ‘_
does notpermit detail illustration of these widths. 70 other apparatus may be utilized in_succe'ssfully
practicing the- invention.
The operation' of the system of Figs.. 4 and 5 is
pipes of square or circular cross section or 'di
" believed to be apparent in view ofI the explana
electrically loaded-pipes may be used in place of
tion given above relative to the two-element sys
the`rectangu1ar- air-filled pipes. Also, any prac
tem. In the case of transmission, _the radiations
from the twenty pipes'add in phasev for direction 75 tical number of pipes may vbe used and, instead
2,411,872
7
.
of uniformly graded pipe lengths do, di, d2 . . .
11.v In combination, a radio transceiver, a plu
rality of air-filled parallel rectangular metallic
ously be non-uniformly graded, provided that the
Wave guides connected thereto and having aper
phase velocities of the pipe are properly propor
tures at their remote ends, said guides having dif
-tioned in accordance with the lengths.
5 ferent physical lengths and diil'erent wide trans
What is claimed is:
,
` `
d20, the physical lengths of the pipes may obvi
verse dimensions, the wide transverse dimension
1. An end-on antenna array comprising a plu
of the longer guide being a function of the phy
rality of open-ended dielectric channels having
sical length of said guide and the phase length
different phase velocity characteristics.
'
of the shorter guide.
_
2. An antenna array comprising a plurality of _ 10
‘12. In combination, a radio translation device.
.open-ended dielectric channels having different
lengths.
a'first open-ended, metallic wave guide connected
‘
thereto and having a given phase velocity and a
3. An end-on antenna array compri-sing a plu
given phase length differing from its physical
rality of open-ended dielectric channels having
length, a second open-ended metallic wave guide
connected to said device and having a greater
different cross-sectional areas.
4. An antenna array comprising a pair of par
`physical length, said guides being parallel and
allel dielectric end-on antenna members having
different physical lengths and different phase
velocity characteristics, the velocity 'diiîerence
aligned With a desired direction of action, said
‘ second guide having a phase velocity diiïering
from that of the ñrst guide by an amount such
being a function of the length diiîerence.
‘
that the difference in phase length of said guides
5. In combination, a pair of parallel end-nre 20 is equal to the difference between the physical
dielectric radiators having different lengths and
length of said guides.
’
,
different widths, the difference in width being a
function of the length diiïerence.
>
6. An antenna array compri-sing a plurality of
13. A dielectric antenna array comprising a pair
of ‘parallel open-ended metallic wave guides
aligned substantially with a desired direction of
parallel rectangular open-ended wave guides
having different wide transverse dimensions, the
open ends of said guides being spaced on the de
action and having diiîerent physical lengthsfsaid
guides having a difference in phase velocities pro
portioned to secure a difference in phase lengths
equal to the diiïerence in their physical lengths.
difference in said dimensions.
14. In»> combination, a translation device, a plu
30
7. In combination, a radio device, a -pair of
rality of dielectric channels connected- thereto '
open-ended Áparallel metallic wave guides con
and having antenna apertures spaced on the path
nected thereto for conveying transverse electric
of desired radio action substantially, the adja
components, »said guides having different physical
cent channels having at least one dimensional dif
lengths and each guide having a physical length
35 ference related to the spacing between the asso
sired wave path an amount dependent upon the
differing from its phase length, the phase length
of one 'guide being equal to the phase length of
the other guide plus said length diiîerence.
‘
8. A dielectric antenna array comprising a pair
of dielectric channels connected to a translation
device and having apertures at their` remote ends, 40
said apertures being spaced on the path of de
sired radio action, said channels having for a
given frequency different phase velocities, the
‘
‘
prising apair of open-ended parallel -dielectric
I
15. An end-on dielectric antenna array com
ceiver for utilizing waves polarized parallelto the
.narrow transverse dimension, said members hav
ing graded lengths and graded transverse wide
dimensions, the transverse Wide dimension of any
to a translation device, said channels having dif
ferent physical lengths and phase velocities dif
fering »by an amount related to the physical length
difference and such -that the difference in -phase
length of said channels equals the difference in
physical length or equals the last-mentioned dif
ference plus or minus a multiple, including one,
intermediate member being a function of the sum
of the length of the shortest member and the dif
ference in length between said intermediate mem
ber and said shortest member.
_ of ajwave-length as measured in the ether.
16. In combination, a translation device, a pair
of dielectric channels connected thereto and .each
having an end vantenna. aperture, said channels
60
having different longitudinal dimensions and dif
ferent phase velocity characteristics för a given
and aidiiïerence in phase length as measured in
wave-lengths in the guides, said guides having a
4difference in their wide transverse dimensions
related to -the physical length diiîerence and se
frequency, the difference in length and the differ
ence in phase velocity characteristic being re
lated to the spacing on the path of desired direc
tion between said apertures.
lected so as to render the phase length difference
`equal to the physical length difference or equal
to the physical length diiference plus a multiple,
CARL B. H. FELDMAN.,
GEORGE' E. MUELLER.
including one, of la wave-length as measured in
the ether.
rection.
ing a narrow transverse dimension and a wide
transverse dimension and connected to a trans
channels having different lengths and connected
' as measured in Wave-lengths in the ether medium
wavelets emitted along said path are cophasal
and form a wave front perpendicular to said di
open-,ended rectangular metallic wave guide hav
9. An end-on dielectric antenna array com
10. ÄAn antenna array comprising a plurality of
open-ended, air-filled, metallic rectangular Wave
guides having a given' difference in physical length
wave-lengths as received at said device from a
Wave traveling on said path are cophasal and the
prising a plurality of end-on dielectric' antenna.
members, each member comprising an air-filled
phase velocity difference being a function of ,the
aperture-spacing.
ciated apertures whereby the relative phase veloc
ities in said adjacent channels are such that the
"Io
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