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Патент USA US2113136

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April 5, 1938. y
Filed Feb. 3. 1936
Patented Apr. 5, 1938
l 2,113,136
Clarence W. Hansell, Port Jeñerson, and Nils E.
Lindenblad, Rocky Point, N. Y., assignors to
Radio Corporation oi' America, a corporation
of Delaware
Application FebruaryÍ s,- isss, sei-n1 No. 62,0111l5 Claims.
This invention relates to antennas.
A primary object is to enable thé transmission
of short radio waves with considerable vertical
directivity and with uniform and maximum
5 radiation in the horizontal plane.
-vA further object is to provide an antenna suit
able for use on ultra high frequencies which has
a broad frequency response curve whereby it will
radiate the modulation sidebands of television,
facsimile and other program services.
Another object is to provide a mechanically
simple antenna structure of pleasing appearance
suitable for use on the tops of high buildings and
A further object is to provide a simple me
chanical antenna arrangement for use with ultra
high frequencies which gives the equivalent of a
series of dipoles energized in the same phase with
respect to one another.
These and other objects of the invention which
may appear from a reading of the speciilcation
are achieved by providing an antenna in the form
of a tube having alternately arranged radiating
‘ sections each a half wave long at the operating
25 frequency and energized such that the currents
flowing therein are in the same direction, where
by cophasal energization is eiïected. The radia
tion from an intermediate section is suppressed
by means of a sleeve also a half wave length
30 long surrounding the intermediate section.
sleeve may be either insulatingly positioned with
respect to or fastened metallically at its mid
point to the antenna tube and is connected to
ground by means of a lead a multiple of a halt
35 wave long extending within the tube from ground
to the end of the sleeve nearest the high fre
quency apparatus.
The diameter of the antenna tube is selected
to give a desired Width of frequency response
curve and is based upon an appreciation of the
fact that the width of the curve is increased
simultaneously with an increase in diameter of
the tube.
A . ature of the invention is the adjustable
sleeve at the extreme end of the antenna tube for
obtaining proper adjustment of the length of
the antenna.
Advantages of the invention are that the an
tenna (1) possesses moderately great vertical
directivity but no horizontal directivity`when
erected vertically; (2) is simple to construct;
(3) is rigid in. construction; and (4) is easily
adapted for use on the top of a high building.
In the accompanying drawing, Figs. 1 and 2
illustrate the invention as applied to two diil‘erent
lengths of antennas mounted vertically on the
top of a~ building. It will be appreciated, of
course, that the antenna may also be positioned
horizontally or at any desired angle for obtain
(Cl. 250-33)
ing directivity in planes other than the vertical l
The antenna of Fig. 1 comprises, essentially,
a single rod l equal to seven-quarters the length
of the communication wave, set one-quarter of
a wavelength more or less into the top of a build
ing. The portion of the antenna above the roof
top consists of two half wavelength radiating
portions 2, 2 separated by an eñective non-ra
diating portion 3 from which radiation is sup 10
pressed by a surrounding sleeve 4 also equal to
a half wave-length. Sleeve 4 is grounded to the
roof top by a half wavelength connection I4
which connects with the sleeve at its lower end `
and extends inside the tubular antenna, as 15
shown. Connection I4 may connect to the inside
or outside of sleeve 4. The lowest quarter wave
length section is prevented from radiating by
having it sunk into the roof of the building. The
antenna is energized by high -frequency appa 20
ratus, shown conventionally in box form, through
transmission line TL which connects with an
tenna l at a tapping point which is adjustable to
match the impedance of the line TL. In this
manner standing waves are set up along the
antenna, and the voltage which is eilîective in
producing radiation is asìindicated in dotted lines
on the sections 2, 2.
Sleeve 4 may be insulatingly positioned, or can
be fastened metallically at its mid-point to the 30
antenna tube 2. If desired, `sleeve 4 may be
grounded at its upper end, in which case con
nection I4 should be an even multiple of half
the length of the operating wave.
An adjustable sleeve 5 aids in adjusting the
length of antenna l. In order to broaden the
frequency response curve of the antenna so that
it may radiate the modulation sidebands, its
diameter is made quite large, herein shown as
one-fifteenth the wavelength.
The system of Fig. 2 is similar to that of Fig. 1
except that the antenna is of greater length.
In Fig. 2 there are shown three radiating sections,
each one-half wave-length separated from one
another by half wavelength non~radiating sec 45
tions in the same manner as shown in Fig. 1.
In this case the uppermost lsleeve 4' is grounded
to the roof top by a conductor equal to three half
Instead of such a grounding ar
rangement for sleeve 4', the lower end of the
upper sleeve 4' can be connected to the upper
end of the lower sleeve 4. It will thus be ap
parent that if the antenna is lengthened, each
sleeve may be connected to ground over a con
nection equal to an odd multiple of a half wave
length. Fig. 2 also diiîers from Fig. 1 by show
ing another way of coupling the transmission line
to the antenna; instead of the direct coupling
of Fig. 1, inductive coupling is used, both types of
coupling being, of course, interchangeable.
It will be understood, of course, that the in
portion o! the antenna above said roof top being
' vention is not limited to the precise arrange
a multiple of a half wave, said roof being ot
high conductivity and maintained at `zero radio
ment shown in the figures, since various modi
fications may be made without departing from
the spirit and scope thereof. For example, the
frequency potential.
9. An antenna in accordance with claim 6, "il
characterized in this that said antenna is mount
ed on the top of a building, the lcwermost por
tion of said antenna being set below the roof top
antennas of Figs. 1 and 2 may be extended sym
metrically from a center so as to form a struc
ture equivalent to two antennas end to end,
for approximately one-quarter wavelength, said
somewhat like an extended dipole antenna. Al
» portion of the antenna above said roof top being 10
10 so, various arrays of antennas may be used to ob
tain additional directivity, It should also be a multiple-of a half wave, said high frequency
understood that the expression “sleeve” is not apparatus being coupled to said antenna at the
necessarily limited to a continuous, solid ele- - portion below said roof top, said roof top being of
ment but also includes a plurality oi?> closely high conductivity and grounded.
10. An antenna comprising two lhalf wave 15
15 spaced, interconnected wires in the form oi' a
screen and having the general configuration of length radiating sections separated by another
a cylinder.
half wavelength section, a sleeve one-half wave
length long surrounding said last section and in
sulated therefrom for preventing radiation there
from, and a connection grounding said sleeve.
11. An lantenna for obtaining moderately great
What is claimed is:
1. An antenna comprising -two half wave
20 length radiating sections separated by another
half wavelength section, and a sleeve one-half
wavelength long surrounding said last section
for preventing radiation therefrom, the ends of
vertical directivity and little or no horizontal
directivity, comprising a vertical rod, high fre
quency apparatus connected to the lower end of
said rod, a sleeve surrounding each alternate half 25
wavelength section of said rod, the portions of ~
said sleeve on both sides of the center being in
sulated from the rod, and a connection a multiple
of a half wave long connecting each' of said
sleeves to ground for preventing radiation from 30
said sleeve on both sides of its center being in
25 sulated from said last section, and a connection
grounding said sleeve.
2. An antenna comprising a straight rod hav
ing high frequency apparatus connected to one
end thereof, alternate half wave sections of
30 which, as measured from the free end, radiate,
the surrounding sections.
12. An antennal comprising a substantially
straight hollow rod, alternate half wave sections
of which radiate, means for preventing radia
means for preventing radiation from each half
wave section located between radiating sections
comprising a sleeve surrounding said section,
the ends of said sleeve being insulatingly posi
tion from each half wave section located be
35 tioned from said antenna, and a connection for
grounding said sleeve.
tween radiating sections comprising a sleeve sur
3. An antenna in accordance with claim 2,4 rounding said section, and a connection inside
characterized in this that said antenna is a tube said rod groundìngsaid sleeve.
13. An antenna comprising a substantially
and said connection grounding said sleeve runs
straight hollow rod, alternate half wave sections 40
40 inside said tube.
4. An antenna in accordance lwith claim .2, of which radiate, means for preventing radia
characterized in this that said antenna is a tube tion from each half .wave section located between
and said connection grounding said sleeve runs radiating sections comprising a sleeve surround
inside said tube, and is an odd multiple of half ing said section, and aconnection inside said rod
Y and insulatingly positioned wth respect thereto 45
45 the length of the operating wave.
5. An antenna comprising two half wave`- for grounding said sleeve, said connection ex
length radiating sections separated 'by another tending to said sleeve through an aperture in said
half wavelength section, and asleeve one-half .
`14. An- ,antenna> comprising a substantially
wavelength long surrounding said last section
50 and supported therefrom only at its mid-point» ~ straight., hollow rod~,‘~¿,alternate lhalf wave sec
>'_ Ítionscf which radiate„means for preventing ra
for preventing radiation therefrom, and a con
nection an odd multiple of a half- wavelengthV diation-from each half 'wave >section located be
long grounding said sleeve. ’
f tween radiating sectionseomprising a sleeve sur
6. An antenna for obtaining moderately great Árorundingsaid` section, and fa' connection inside
55 vertical directivity and little or no'horizontal-f
directivity, comprising a vertical rod, -high >fre
saidl rod-grounding- said' `slee've,`.j-.said connection
. beingra, multiple o'ft'half «the length of the' operat.`
quency apparatus connected to the lower end
ing-Wave. u
>15.*_An ' antenna vcomprising a substantially
of said rod, an adjustable sleeve, at the >ex- ,
treme top end of said rod for adjusting the length vvertical hollowrod, alternate vhalf wave sections
of which radiate,‘saidyrodubeingmounted on a 60
` wavelength section _of saidv rod and> insulated _grounded'support 'andbein'g " ¿below the upper
d `
therefrom, and a_.connection an odd multiple of ’ Isurface of said supportvffor
60 thereof, a sleeve surrounding each alternate half »
a halfy wave longïconneoting each of said last - " mately, one-quarterathejflength' of the operating y
wave, said'portionhaboveisaid support being a
multiple 'of half :the operating wave, ’means for 7. An antenna in> _accordance with claim 16, >preventing radiationi'rom' e‘ach half wave sec
characterized in A`this that said rod _is altube whose t tion of saidfrod located ¿ between radiating >sec
outer diameter is anvappreciable fraction of- a tions ,c'omprising' a‘shieldsurro'unding said sec
half wave long, and' said 'connections'.extend tion, av connection inside said rod grounding said
sleeves and ground ¿for preventing radiation from
the 'surrounded"fsecfftionvs_.
70 within said tube from said sleeves togroundi -`
wsliieldr' and high frequency apparatus coupled
8.» An antennal ‘in accordance with 'claim` 6,'v .tosaid rod atfthe -portion below the upper sur
characterized in this. that-said antenna'is mount- . face of> said' support.: e
ed on the topfoii> a- building,_the lcwermost por- _ Y
tion of said antenna beingy set -below the roof top
75 for approximately o'rie-ciui'trtery wavelength, said ì
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