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Патент USA US3095557

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June 25, 1963
J. F. ZALESKI
3,095,547
HIGH SPEED MICROWAVE SWITCH UTILIZING GYROMAGNETIC ELEMENT
Filed May 28, 1959
30
3 Sheets-Sheet 1
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1
INVENTOR.
JOHN F. ZALESKI
BY
7mg?
ATTORNEY
June 25, 1963
J. F. ZALESK]
3,095,547
HIGH SPEED MICROWAVE SWITCH UTILIZING GYROMAGNETIC ELEMENT
Filed May 28, 1959
3 Sheets-Sheet z
MICROWAVE J49
SOURCE
5|)
MICROWAVE
LOAD
INVENTOR.
JOHN F. ZALESKI
BY
ATTORNEY
June 25, 1963
J. F. ZALESKI
‘
3,095,547
HIGH SPEED MICROWAVE SWITCH UTILIZING GYROMAGNETIC ELEMENT
Filed May 28, 1959
3 Sheets-Sheet 3
INVENTOR.
JOHN F. ZAhESKl
BY
ATTORNEY-4
United States Patent 0. 1C6
3,095,547
1
1
Patented June 25, 1963
2
Still another purpose is to provide a microwave pulse
modulator.
Still another purpose is to provide an electrically-‘oper
3,095,547
HIGH SPEED MICROWAVE SWITCH UTILIZING
GYRQMAGNETIC ELEMENT
John F. Zaleslri, Pleasantville, N.Y., assigncr to General
Precision, Inc., a corporation of Delaware
ated attenuator for insertion in a microwave transmission
line.
A further understanding of this invention may be se
Filed May 28, 1959, Ser. No. 816,417
3 Claims‘. (Cl. $33-$42)
cured from the detailed description and associated draw‘
ings, in which:
This invention relates to high speed microwave switches
which operate by abruptly changing the power-carrying
properties of ‘a waveguide.
Microwave switches of this description have been used
as duplexers for ‘radar apparatus and similar systems
FIGURE 1 depicts one form of the invention in which
a ferrite component is axially centered in :a round wave
guide, the component being penetrated by an axial wire.
vFIGURE 2 depicts one form of ferrite component con
sisting of a ferrite tube wrapped with a wire helix.
FIGURE 3 depicts another form of ferrite component
wherein a single antenna is used for both transmission
and reception. One such switch is the well known trans 15 consisting of a ferrite tube surrounded by a number of
close-?tting metal bands.
mit-receive, or TR switch, and another an antitransmit
FIGURE 4 ‘depicts another form of ferrite component
receive, or ATR switch. The present switch serves the
consisting of a ferrite tube surrounded by, a dielectric
same purposes, as well as other purposes, but operates
sleeve.
on entirely different principles.
In the present switch a tube of ferrite material is posi 20
FIGURE 5 depicts another embodiment of the inven
tion utilizing Ia rectangular waveguide shunt T with the
tioned in the longitudinal axis of a waveguide through
‘which microwave energy is to be passed. ‘One or more
magnetic ?eld sources located near the ferrite tube gen
erates a unidirectional magnetic ?eld ‘at the ferrite tube.
ferrite component and the Xaxial wire in its shunt arm.
FIGURE 6 depicts still another embodiment of the
invention utilizing a rectangular waveguide containing
An electrical conductor is positioned in the bore of the 25 the ferrite component and surrounded by a magnetizing
coil winding. The fer-rite component is supported by
ferrite tube with its two ends brought outside of the
an H-rod structure which ‘also serves as the axial con
waveguide, and a switching current, which may have the
ductor and its terminal leads.
form of a current step or of a pulse train, is passed
Referring now to FIG. 1, ‘a round hollow waveguide
through this electrical conductor. When this is done an
11 is designed to support X-band microwave transmission,
electrical load at the output end of the waveguide receives
microwave energy of greatly changed magnitude during
for example, at 8800‘ me. p.s. This waveguide .11 is con
the step or pulse.
nected through broad-face transitions to two rectangular
waveguides 12 and 13. These waveguides 12 and 13
7
I
The ferrite tube may be composed of any selected fer
rite material such as, for example, ferramic R41, made
by General Ceramics Corp., Keasbey, N .J . This material
is composed of iron, manganese and magnesium oxides in
the molecular proportions of 22Fe2O3, 8MnO2, and
'70MgO.
are terminated in short-circuited stubs 14 and 16, and
employ other .conventional devices as required for match
ing the transitions so that, when microwave energy in
the dominant mode is applied to waveguide 12, it is trans
formed by the transition to the round waveguide 11,
through which it is transmitted in the dominant mode or
The operation of the switch is greatly enhanced by ‘ap
plying a conductive wire helix, la series of metal bands, or 40 other suitable mode. The energy is then retransformed
to the rectangular waveguide dominant mode and trans
a dielectric cylinder to the outside surface of the ferrite
mitted out waveguide 13 to‘ a microwave load.
tube. The waveguide is preferably hollow, land may be
Although the waveguide 11 is designated as :a round
either round or rectangular in form, or may be a contin~
waveguide section, rectangular waveguide may alterna
uation of a coaxial line. The ferrite tube is supported in
such manner that the supports offer minimum impedance 45 tively be employed.
The round waveguide 11 contains a ferrite component
‘discontinuity to the microwave energy carried by the
waveguide. Any discontinuities that are offered by the
17 centered axially therein. The ferrite component 17
supports and by the two ends of the ferrite tube may be
matched or tuned out by two adjustable susceptances
positioned in the waveguide, one in front of the ferrite
has an axial hole through which runs an electrical wire
be employed in connection with a radar antenna to
switch the ‘direction of the radiated microwave beam. In
or more polyfoam cylinders.
conductor 18. This wire, in addition to its electrical func
tions, may support the ferrite component ‘17 mechani
cally. Alternatively, the ferrite component 17 may be
tube and the other behind it.
7
supported so as to remain centered in the waveguide by
The present invention is useful as a duplexer and to
electrical insulators which negligibly distort or impede
protect radar receiver semiconductor diodes from burn
microwave ?eld energy carried by the waveguide. For
out by the transmitter pulses. The invention may also 55 example, the ferrite component may be supported by one
The wire 18 is led outside the waveguide system through
all of these uses the high speed operation of the switch
choke ?ttings 19 and 21, the metal pipe extensions 22
gives it an advantage. This speed of operation is indi
and 23 of which serve, together, with the coaxial wire
cated by the small waveform deterioration sutfered by 60 18, to form two pairs of coaxial conductors 24 and 26
modulating pulses transmitted through the switch, this
forming external terminals for the wire centered in the
ferrite component.
deterioration being only of the order of 0.005 micro
second.
One purpose of this invention is to provide a high
speed microwave switch which has no moving parts.
The ferrite component 17 consists of a ferrite tube
made, for example, of ferramic R-l as more speci?cally
65 described above, and having a length of one and a half
inches, an external diameter of one-quarter inch and a
Another purpose of this invention is to provide a de
bore diameter of one-eighth inch. Two short permanent
vice to open or close a microwave circuit at high speed,
magnets in tube form are applied to the two ends of the
analogous to a single-throw switch in a wire circuit.
ferrite tube, with opposed magnetic ?elds, as depicted by
Another purpose is to provide a microwave device to
70 the magnets 27 and 28, FIG. 2. .These magnets are se
perform the functions of a radar transmit-receive or ranti
cured by mortising and cementing to the two ends of the
transmit-receive switch but at greatly increased speeds.
ferrite tube 29. The ferrite tube 29 is wrapped with an
_
3,095,547
1
4
external helix or bare copper wire 31, closely ?tted directly
waveguide 37, the exit being provided with a choke to
thereto and in mechanical and electrical contact therewith.
prevent escape of microwave energy. A metal sleeve 46
The end 32 and 33 of the helix are left unconnected. The
wire diameter is 0.020 inch and the helix has 25 turns per
inch. The wire 18, FIG. 1, is centered in the ferrite tube
connected externally to the waveguide 73 at this point,
surrounds and is insulated from the conductor 42 as it
emerges and, with the conductor, constitutes a coaxial
bore by two insulating plugs 30 and 35, FIG. 2, which
conductor terminal pair for the application of switching
?t the bore and are drilled for the wire. Such an arrange
pulses or steps to the wire within the ferrite tube. The
return of this circuit is, of course, through the material
ment is advisable at high pulse train frequencies in order
to interpose space separating wire from the ferrite
material, thus reducing capacitive loss.
Although these dimensions and speci?cations are pre
ferred, they may be widely varied without extreme degra_
dation of results. The ferrite tube may have any length,
but generally the effects produced thereby are proportional
to its length. The ferrite tube external diameter may
of the waveguide from the cross-conductor sidewall junc
10 tion 33’ to the tube 16. A permanent magnet 47 is posi
tioned outside of the waveguide sidearm 38 parallel to the
ferrite component 41 within. The permanent magnet 47 is
secured to the broad face of the wavegmide sidearm 38 but
is separated from it by a non-magnetic shim 48 of adjust
able thickness. The purpose of this shim is to control
the strength of magnetic ?eld applied by the permanent
be varied, but should not be made so large that the
magnet to the ferrite component.
ferrite occupies a major part of the volume of the wave
In the operation of this device, microwave energy is
guide. The wire helix may be replaced by a series of
transmitted from a source 49, through the waveguide 37,
electrically conductive bands, such as the metal bands
34 of FIG. 3. The wire helix may also be replaced by a 20 to a load 51. In the absence of current through con
ductor 42, the position of the short-circuiting plunger 39
dielectric sleeve 36 as shown in FIG. 4, which is made of
is adjusted until a short circuit is re?ected to the junction
Stycast, made by Emerson-Cummings Co. This sleeve
of the sidearm 38 with the waveguide 37. This distance
has an external diameter of three-eighths inch and a
is schematically indicated by the dimension ‘D, and is equal
dielectric constant of 4.
The wire helix, when used, may be variously con 25 to a multiple of one-half wavelength in the sidearm. The
sidearm then does not interrupt the waveguide 37 trans
structed of any conductive wire of gauge between 20 and
mission to the load 51. It now a ‘direct-current step or
40 AWG, tinned or bare, spaced variously between turns.
pulse train be generated by generator 52 and applied to
In general, spacing from the surface of the ferrite tube
the wire 42, the circumferential magentic ?eld around the
degrades the results in proportion to the amount of spac
ing. The permanent magnets 27 and 28, FIG. 2, may be 30 wire 42 so affects the microwave properties of the ferrite
component as to change the electrical length of the elec
positioned in aiding position, as in FIG. 3, instead of in
trical path having the dimension D. The electrical length
opposing position as in FIGS. 2 and 4. Other means of
is caused to depart from a half wavelength multiple, and
applying a stationary magnetic ?eld to the ferrite tube
with an appropriate amplitude applied from generator 52
may be employed, examples of which will be given later.
the electrical length is changed to an odd multiple of
In the operation of the embodiment of FIGS. 1 and 2,
one-quarter wavelength in the waveguide. The input
let it be assumed that microwave energy at a frequency
microwave energy now encounters an open circuit or
of 8800 mc. p.s. is applied to the waveguide 12, and that
high impedance at the sidearm, and energy transmitted
the coaxial conductor terminal pairs 24 and 26 are un
to the load 51 is greatly reduced.
connected. The applied microwave energy will then be
By changing the position of the plunger 39 the opera
available at the output waveguide 13 for application to 40
a load, the device causing an insertion loss of about 0.3
db. Now let be supposed that a pulse train is applied
between the terminals 24 and 26. This train has a fre
quency of 5000 c.p.s. and consists of rectangular 1 ,us.
pulses. The maximum rise or fall time of each pulse is
about 0.02 ,us. Measurement at the output microwave
terminal 13 now discloses that during each pulse the
energy available at the output terminal 13‘ is a few percent
of the applied energy and that the degradation of the
waveform is negligible. Thus the device constitutes a
fast and e?icient on-o? microwave switch.
These results show that the switch is operable up to
tion can be reversed, and energy will be transmitted to
the load only when the wire 42 is energized.
FIG. 6 depicts an embodiment in which a rectangular
waveguide is adapted to transmit microwave energy from
one end 54 to the other end 56. A ferrite component 57
is of any one of the types described in connection with
the preceding drawings. A stiff conductive wire 58 passes
through the bore of the ‘ferrite tube and is mechanically
and electrically secured, as by welding, soldering, or
riveting, at either end to two cross members 59 and 61.
These members are also made of stiif conductive wire,
and pass out of the waveguide through holes in the nar
row side walls thereof, such as the hole 62. These holes
a pulse train frequency limit of some 50 or 100 mc. p.s.
may be protected by the usual choke constructions, not
and also may be employed down to a direct-current limit,
that is, to switching by a single step change in direct 55 shown in the drawing. Insulating sleeves in the holes
62, or in the choke constructions if used, mechanically
current applied to the axial wire.
suppont the members 59 ‘and 61, and through them and
FIG. 5 depicts {another embodiment of the invention.
the wire 58 also support the ferrite component 57. The
A rectangular waveguide 37 is provided with sidearm 38
members 59 and 61 are at right angles, within the wave
to constitute a shunt or H-plane T. The sidearm 38 is
terminated in a movable plunger 39 constituting an ad 60 guide, to the microwave electric ?eld, so that currents in
justable short circuit. A ferrite component 41 is axially
the members cannot interact with the ?eld.
The wave
guide 53 is surrounded, in the vicinity of the ferrite com
positioned within the sidearm 38. This component con
ponent 57, by a coil 63 having a pair of terminals 64 for
sists of a ferrite tube with a covering, and does not in
connection to a direct-current source, whereby the coil
clude the permanent magnet end cylinders shown in
FIGS. 2, 3 and 4. Except for the absence of these perma 65 generates a ‘longitudinal magnetic ?eld at the ferrite
component.
nent magnets, the ferrite component is identical with that
It is possible, and may be advantageous in special
described in connection with preceding ?gures. The fer
cases, to combine any or all of the continuous magnetic
rite component contains a central conductor 42, as before
?eld generating means 1described in connection with all
described. This conductor is terminated at one end on
a cross wire 43 to which it is conductively secured. The 70 six ?gures.
The waveguide 53, FIG. 6, is provided with two ad
cross wire 43 is positioned transvei'sely in the arm 38, and
is secured to its narrow walls. This cross wire is thus
perpendicular to the waveguide axis and to the narrow
justable susceptan'ce matching or tuning devices. These
devices may simply be screw stubs 66 and 67 in the
median line of a waveguide broad face, adjustable in
waveguide faces. The other end of the central conductor
42 is brought Out through the narrow wall 44 of the 75 length between zero intrusion within the waveguide and
3,095,547
6
an intrusion equal to not more than one-quarter wave
and means applying to said conductor a switching cur
rent having at any instant one of two magnitudes where
length in free space. The distance M between the screws
is equal to an odd multiple of one-quarter wavelength
by when the current has one magnitude said main section
within the waveguide between the screws. This wave
is interdicted and when the current has the other magni
length in guide is determined under the condition of no 5 tude said main section is microwave transmissive.
current in the wire '58 but with the continuous magnetic
2. A microwave switch comprising, a rectangular
?eld or ?elds in operation.
waveguide, means for applying microwave energy to one
In the operation of this embodiment, with a direct
end thereof, load means for extracting microwave energy
current source connected to terminals 64, the screw 66
from ‘the other end thereof, a ferrite component posi
is adjusted ‘for minimum voltage standing wave ratio 10 tioned coaxially in said waveguide, discontinuity match
between it and the microwave source connected to the
ing means positioned in said wave guide between one end
waveguide end 54. Most of the microwave energy will
thereof and said ferrite component, another discontinuity
then be transmitted [to the waveguide end 56 and out to
matching means positioned in said waveguide between
the load connected thereto. The screw 66 will compen
the other end thereof and said ferrite component, a mag
sate for the discontinuities caused ‘by the screw 67 and 15 netizing coil wound around the outside of said waveguide
by the ferrite component and its supports. The trans
adjacent said ferrite component and coaxial therewith,
mitted bandwidth will be generally inversely proportional
means applying direct current to said coil, an electrical
to the depths of insertion of the screws. If now a pulse
train or a step current be applied to the support wires,
ponent, vand means applying to said conductor a switch
conductor extending axially through said ferrite com
for example to the ends 68 and 69, from the generator 20 ing current having at any instant one of two magnitudes
whereby ‘when the current has one magnitude said wave
guide is microwave transmissive while at other times said
71, the microwave transmitting properties of the section
of waveguide containing the ferrite component Iwill be
modi?ed during the step or during each pulse, with the
waveguide is nontransmissive.
result that the microwave energy reaching the load is
reduced.
.
3. A microwave switch in accordance with claim 2 in
25 which said electrical conductor is connected at each end
In some cases it may be desirable to employ a step or
to one of two support conductors, the two support con
pulse modulation on the wire 58 which varies between
ductors being disposed at right angles to the electrical
two values of direct current instead of between zero and
conductor, the support conductors conducting current to
a single value. That is, continuous direct current and
and from the electrical conductor and providing mechan
pulse current may be combined in the external circuit 30 ical support, each support conductor penetrating a nar
row side of said rectangular waveguide.
by means of frequency combination components, and the
combined signal applied to terminals 68 and 69‘.
What is claimed is:
l. A microwave switch ‘comprising, a rectangular
waveguide shunt T having a main section and a shunt 35
sidearm joined thereto, means for applying microwave
energy to one end of said main arm, load means for
extracting microwave energy from the other end of said
main arm, a conductive plate short-circuiting the end of
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,671,884
Zaleski ______________ __ Mar. 9, 1954
2,798,205
2,885,677
2,906,974
Hogan _______________ __ July 2, 1957
Zaleski _______________ __ May 5, 1959
Reggia _____________ __ Sept. 29, 1959
2,920,292
2,951,220
a permanent magnet positioned adjacent said ferrite com
ponent outside of said shunt sidearm, an electrical con~
2,994,841
Scovil ________________ __ Jan. 5, 1960
Miller ______________ _._ Aug. 30, 1960
Zaleski ______________ __ Aug. 1, 11961
ductor extending axially through said ferrite component,
202,013
Australia _____________ __ June 6, 1956
said shunt sidearm distal to said main section, .a [ferrite 40
component positioned coaxially in said shunt sidearm,
FOREIGN PATENTS
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