close

Вход

Забыли?

вход по аккаунту

?

код для вставки
Nov. 6, 1962
L. DAVIS, JR
I MICROWAVE STRIP TRANSMISSION LINE CIRCULATOR
3,063,024
s
Filed Feb. 29, 1960
44
20
y/4 46
50
//v|/EA/7'0/?
LUTHER DAV/.5; JR.
BY w 31...
TTOR/VEY
United States Patent Q??ce
1
3,063,024
MECRDWAVE STRIP TRANSMISSION
LINE CIRCULATGRS
Lather Davis, Jr” Wayland, Mass., assignor to Raytheon
Company, Lexington, Mass, a corporation of Dela
ware
Filed Feb. 29, 1960, Ser. No. 11,740
5 Claims. (Cl. 333-11)
Brim“
Patented Nov. 6, 1962
2
later body includes a pair of parallel ground plane mem
bers held in spaced-apart relationship by a peripheral
cover member.
Three coaxial connectors are disposed
about the peripheral cover in symmetrical relationship,
with the center conductor of each of the connectors being
connected to the outer end of a respective one of the
three arms of a conductive spider member which is posi
tioned midway between and parallel with the ground
members to provide a strip transmission line con
This invention pertains generally to microwave circu l0 plane
?guration of three branches.
lators, and more particularly to improved ferrimagnetic
In order to obtain circulator action, a pair of ferrimag
microwave circulators employing strip transmission line
netic members are positioned substantially centrally with
con?guration. As employed herein, the term “ferrimag
in the circulator, one on either side of the central portion
netic” is intended to connote materials having negligible
electrical conductivity and exhibiting either ferrimagnetic
or ferromagnetic effects.
Ferrimagnetic materials ?nd wide use in microwave de
vices as the art advances. Exemplary of devices employ
of the spider member, and a magnetic ?eld of ?xed in
15 tensity is established within the ferrite member in a di~
rection perpendicular to the spider and ground plane
members. As will be understood by those skilled in the
art, this steady-state magnetic ?eld is of an intensity
ing magnetized ferrimagnetic materials are gyrators, iso
lators, directional phase shifters and circulators. Circu~ 20 amplitude which is signi?cantly removed from (being
either greater or smaller) that connected with ferrimag~
lators are considerably more complicated circuit elements
netic resonance at a given microwave frequency and for
than, for example, isolators, and the uses proposed for
a given geometry. The three coaxial connectors con~
them are typically more sophisticated than those for iso
stitute the ports of the circulator, and a signal applied to
lators. An important distinction between circulators and
a ?rst of these ports effectively appears at only a second
isolators is that the former diverts or otherwise makes
port,
with signals applied to the second port appearing
use of input power, rather than destroying it, as does the
only at the third, and so on, for a given ?eld polarity of
latter. It is a basic characteristic of microwave circu
magnetic energization. With the D.-C. magnetic ?eld
lators that energy introduced into a ?rst port will be pre
.reversed, the sense of the commutation between ports is
sented (ignoring losses) as an output solely at a second
reversed.
port (for a given set of operating parameters), energy at 30
With the above considerations and objects in mind the
such second port appears at only a third port, and so on,
invention itself will now be described in connection with
with substantial isolation being provided between a se
lected input port and all other ports except the particular
a preferred embodiment thereof given by way of example
and not of limitation, and with reference to the accom
output port. The term “circulator” thus connotes a com
panying drawings, in which:
.
mutation of power from one transmission terminal to 35
FIG. 1 is a plan view of the microwave circulator of
another.
It is well known that a magnetized ferrirnagnetic body is
an anisotropic medium, and that a microwave device in
cluding such a body may be electromagnetically asym—
metrical even though it has geometrical symmetry. It is
this asymmetry of electromagnetic characteristics that
renders ferrimagnetic devices the interesting and useful
tools that they are, and different theories (based upon
?eld displacement and perturbation theory, for example)
the present invention, with the D.-C. magnetic ?eld
means being removed for the sake of clarity.
FIG. 2 is a sectional view taken on line 2—2 in FIG. 1.
FIG. 3 is a fragmentary elevation view of a modi?ca
tion of the device shown in FIGS. 1 and 2.
In the exemplary embodiment shown in FIGS. 1 and 2,
a pair of circular ground plane members 10 and 12 are
shown mounted in parallel spaced-apart relationship by
have been advanced as to the basis for such asymmetric
means of a peripheral cover member 14, with the plates
10 and 12 and the cylindrical member 14 together form
The anisotropic electromagnetic properties of mag
netized ferrimagnetic bodies have been utilized by prior
ing the body of the circulator. These three members are
of electrically conductive material, and may convenient
ly be secured together by a plurality of threaded fasteners
16 disposed about the peripheries of the two plates'ltl and
characteristics.
workers in the art to provide Y-junction and other circu
lators of hollow waveguide con?guration, and these prior 50
12. A plurality of coaxial connectors 18, 2t} and 22 are
art devices have proven satisfactory for some applica
symmetrically
disposed about the cover member 14 to
tions. However, these prior art circulators have lacked
form the ports of the circulator. The center conductors
sufficient electrical bandwidth in many applications. In
24, 26 and 28 of the three coaxial connectors are con
addition, the size and width of the devices of the prior
art are often greater than can be tolerated in many in on Or nected to the ends of respective arms of a conductive
spider member 30, such spider member having a central
. stances.
Further, the adequate dissipation of heat from
portion 32 in substantial registry with the central portions
the ferrimagnetic members of prior circulators has been
of the ground plane members 10 and 12..
dif?cult.
As will be evident to those skilled in the art, energy
It is accordingly a primary object of the present inven
tion to provide a microwave circultaor of relatively 60 in coaxial lines connected to the connectors 18, 2t)‘ and
22 will be propagated into the circulator of the present
small and lightweight construction.
invention by means of the strip transmission line con?ura
An additional object of the present invention is to
tion of the components therein, and, similarly, micro
provide a microwave circulator being characterized by an
wave energy within the circulator will be propagated by
increased electrical bandwidth.
Another object of the present invention is to provide 65 such strip transmission line con?guration to one or more
of the ports formed by the connectors 18, 2t) and 22, for
a microwave circulator having improved heat-dissipation
transmission through coaxial lines connected thereto.
characteristics.
In order to render this three port strip transmission
In accordance with the present invention, the above
line junction a circulator, a pair of ferrimagnetic bodies
and other objects are achieved by means of a microwave
circulator device employing strip transmission line con 70 34 and 36 are suitably mounted (by means not shown)
on opposite sides of the conductive spider member 3%,
?guration, as opposed to hollow waveguide members.
and in substantial registry with the central portion 32
In the exemplary embodiment described herein, the circu
thereof. The particular composition of the members 34
3,063,024
and 36 is not a necessary element of the present inven
tion, and any substantially electrically nonconductive ma
terials exhibiting ferrimagnetic or ferromagnetic effects
may be employed. Yttrium iron garnet polycrystalline
materials are exemplary for this purpose.
In the operation of the device depicted in FIGS. 1 and
2, a steady-state or D.-C. magnetic ?eld is applied to the
ferrite bodies 34 and 36 in one sense or the other in a
4
shown in FIG. 3 is substantially the same as that de
scribed in connection with FIGS. 1 and 2, with the D.-C.
magnetic ?eld being applied to ferrimagnetic members 40
and 42 by a suitable magnet the pole pieces 48 and 50
of which are shown in FIG. 3. Where circulator action
or commutation is desired in but one direction, the pole
pieces 48 and 50 may form a part of a permanent magnet
of appropriate polarity. On the other hand, where it is
desired to reverse the sense of the circulator operation,
direction substantially perpendicular to the plane of the
spider member 30, such applied magnetic ?eld being sche 10 it is necessary to reverse the sense of the applied D.-C.
matically indicated by the dot-dash lines 38 in FIG. 2,
and being of a magnitude which is removed from (being
either signi?cantly greater or smaller) that connected
with ferrimagnetic resonance at the applied microwave
frequency and for the given geometry. With the D.-C. 15
magnetic ?eld passing through ferrimagnetic bodies 34
magnetic ?eld. Suitable means for achieving such ?eld
reversal are indicated schematically in FIG. 3 by the
solenoid '52 which is energized by a D.-C. source 54
through a reversing switch 56. Upon reversal of switch
56 from one position to another, the magnetic ?eld pass
ing through members 40 and 42 is reversed in polarity,
and the circulator action is correspondingly reversed.
The invention has been described above in some detail,
and 36 in a selected direction (e.g., into the drawing
page of FIG. 1), microwave energy introduced into the
and with particular reference to the application of strip
circulator at the port formed by coaxial connector 18
will appear as an output (neglecting losses) at the port 20 transmission line con?guration to a three port Y-junction
circulator. However, it will be evident to those skilled
formed by connector 20, with no effective output appear
in the art that the invention is equally applicable to cir
ing at connector 22. With the D.-C. magnetic ?eld main
culators having other than three ports therein. In addi
tained in this same direction, a singal applied to con
tion, the circulator ports may take the form of hollow
nector 20 will appear as an output signal at connector 22
with no effective coupling toward connector 18. Simi 25 waveguide connectors with central coupling loops being
connected to the outer ends of the arms of the strip trans
larly, with the D.-C. magnetic ?eld maintained in this
mission line spider member. Further, it will be under
?rst polarity, an input signal at connector 22 will produce
stood that the strip transmission line structure of the
an output at only connector 18. Thus, a commutation
present invention need not necessarily be in the form of
of signals in a given direction between the several ports
of the circulator is achieved. Where the polarity or 30 a central conductor between two spaced-apart ground
sense of the applied D.-C. magnetic ?eld is reversed from
planes. Instead, the device of the invention may equally
that ?rst assumed herein, the direction of commutation
well comprise the spider member disclosed herein and
between ports is also reversed, and an input at connector
only one ground plane member. In such con?guration,
18 appears as an output at connector 22, et cetera.
the spider and the ground plane member would be
FIG. 3 shows a modi?cation of the device of FIGS. 1 35 mounted in parallel spaced-apart relationship with a ferri
and 2, with corresponding elements bearing like refer
magnetic member therebetween, with a source of D.-C.
ence numerals. Thus, the ground plane members 10
magnetic ?eld, and a plurality of appropriate connectors
and 12 are supported in parallel spaced-apart relation
suitably matched to the strip transmission line structure
ship by means of the cylindrical cover member 14, the
40 so formed. Thus, the invention is not to be considered
latter having a plurality of coaxial connectors (one of
as limited to the particular details given, nor to the speci?c
which is indicated at 20) mounted thereon. The conduc
application to which reference has been made during the
tive spider member 30 is mounted within the circulator
description of the device, except insofar as may be re'
body substantially midway between and parallel with the
quired by the scope of the appended claims.
ground plane members 10 and 12, with the outer ends of
What is claimed is:
the spider arms being connected to the center conductors
1. A circulator comprising a plurality of strip transmis—
(one of which is indicated at 26 in FIG. 3) of respec
sion lines coupled together at a common point, said trans
tive ones of the coaxial connectors mounted on cover
mission lines being oriented with their axes de?ning equal
member 14.
angles, each line including a center conductor disposed
A pair of ferrimagnetic members 40 and 42 are
between two outer conductors, means electrically con
mounted on opposite sides of the spider memebr 30, and 50 necting together the center conductors of each of said
in substantial registry with the central portion 32 thereof,
transmission lines at said common point, at least one body
as well as with the central portions of ground plane
of ferrite material disposed at said common point be
members 10 and 12.
In contrast to the ferrimagnetic
tween said center conductor and one of said outer con
members 34 and 36 shown in the preceding ?gures of
ductors, at least one other body of ferrite material dis
the drawing, members 40 and 42 are of su?icient thick 55 posed at said common point between said center conduc
ness to result in a closely contiguous relationship be
tween the upper and lower faces thereof, respectively, and
the opposing areas of the inner faces of ground plane
tor and said other outer conductor, and means magnetiz
ing said ferrite bodies in a direction substantially parallel
to the electric ?eld of waves conducted by said lines and
members 10 and 12. The intimate contact between the
with a strength such that electric waves conducted by
upper face of member 40 and the contiguous face of 60
each of said lines couple to only one other of said lines
ground plane member 10 results in an ef?cient heat trans
and said last-mentioned coupling is nonreciprocal.
fer between the ferrite 40 and the member 10. Similarly,
2. A circulator as in claim 1 and in which said outer
e?icient heat transfer takes place between the lower face
conductors of each of said transmission lines extend sub
of member 42 and the upper face of member 12. As is
common with microwave devices employing ferrimag 65 stantially beyond ‘the edge of the associated center con
ductor.
netic members, considerable quantities of heat may be
3. A circulator as in claim 1 and in which each of said
generated within the members 49 and 42, and the good
strip transmission lines couples to a separate connector at
thermal contact between these members and the respec
tive ground plane members provides a ready sink for such
the same distance from said common point.
heat. To improve the efficiency with which such heat
4. A circulator as in claim 1 and in which each of said
may be dissipated, cooling chambers 44 and 46 are pro
bodies of ferrite material has at least one dimension par
vided in intimate contact with the outer faces of mem
allel to a common plane which is greater than at least
bers 10 and 12, and a suitable coolant is circulated through
one dimension of said center conductors parallel to said
such chambers by means not shown.
It will be understood that the operation of the device 75 common plane.
5
3,063,024
6‘
5. A circulator as in claim 1 and in which said outer
OTHER REFERENCES
conductors are common to all said lines and are substan
tially ?at parallel plates and the outer peripheries of said
outer plates are connected together by electrically conduc
tive material.
“Electrical Manufacturing,” February 1959, pages
Aulbl: “IRE Transactions on Microwave Theory and
5 Techniques,” April 1959, pages 238-246.
Swanson et al.: “1958 IRE Wescon Convention Re
cord—Part 1,” pages 151-156.
UNITED STATES PATENTS
Chait et al.: “NRL Progress Report,” March 1958
2,946,966
Crowe _______________ __ July 26, 1960 10 (made available to public through OTS on Apr. 11,
1958), page 50.
2,978,649
Weiss _______________ __ Apr. 4, 1961
References Cited in the ?le of this patent
3,015,787
Allin et a1. ____________ __ Jan. 2, 1962
Seidel: “Journal of Applied Physics,” February 1957,
pages 218-226.
Документ
Категория
Без категории
Просмотров
0
Размер файла
451 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа