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Патент USA US3092801

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J1me 4, 1963
R. L. HUBBELL ET AL
3,092,791
MICROWAVE swncnms DEVICE HAVING MOVEABLE JUMPER
FOR INTERNALLY SHORTING ELECTRODES OF T-R TUBE
F'iled March 8. 1961
'3:
25
2_f 2 6
28
FIGZ
INVENTORS
RICHARD L. HUBBELL
FRANK A. RECORD
ATTO R N EY
United States Patent 0
we
3,d92,791
.
ICC
Patented June 4, 1963
1
Z
3,092,791
invention with a portion of the tube envelope broken
away to reveal internal structure;
FIG. 2 is ‘an enlarged detailed view of the embodiment
shown in FIG. 1 along the line 2—-2.
Referring now to the drawing, the illustrative embodi
MICROWAVE SWITCHING DEVICE HAVING
MOVEABLE JUNIPER FOR INTERNALLY
SHORTING ELECTRODES 0F T-R TUBE
Richard L. Hubbell, Arlington, and Frank A. Record,
Danvers, Mass., assignors, by mesne assignments, to
Varian Associates, Palo Alto, Calif., a corporation of
California
ment is 1a broad band TR switching tube comprising a sec_
tion of rectangular waveguide 1 de?ning parallel broad
walls 2 and narrow walls 3.
Secured adjacent the ends
Filed Mar. 8, 1961, Ser. No. 94,297
are conventional mating ?anges 4 and 5. A resonant win
5 Claims. (Cl. 333—13)
dow assembly 6 encloses each end of the waveguide sec
10
tion to thereby provide a hermetically sealed envelope.
The present invention relates vgenerally to microwave
Each window assembly includes a dielectric member per
frequency gaseous discharge switching devices with inte
gral protective mechanisms and, more speci?cally, to a
novel and improved mechanism for attenuation of unde
sirable microwave frequency signals.
Prior art switching devices incorporated in radio direc
vious to microwave energy signals. The envelope con
tains a ‘gaseous ionizable atmosphere under reduced pres
sure to provide a highly intense gaseous discharge when
high power microwave frequency energy is transmitted
to the window assembly positioned within ?ange 4.
tion and ranging systems are coupled between the com
Disposed transversely within the waveguide envelope at
mon antenna and the sensitive receiver. A speci?c group
intervals of a quarter of a wavelength are a’ plurality of
vof such devices is commonly referred to as transmit
resonant elements. Included are a plurality of paired
receive 01' TR tubes. An internal highly ionized gaseous
metallic plate members 7 de?ning irises 8. Disposed
discharge within a metallic or dielectric envelope is initi
within each iris are spaced oppositely disposed conical
ated upon exposure to high power pulses transmitted to
electrodes 9, 10, 11, 12 de?ning ‘discharge gaps 13 and 14,
the common ‘antenna. The re?ected returning pulses at
having axes taken in the direction of a discharge across
a lower power level pass through the TR tube without *a
discharge to the receiver. It is necessary to protect the 25 the gaps. An ignitor electrode 15 having a metallic probe
16 and dielectric bead 17 is supported by a ‘collar 18 with
sensitive elements within the receiver during nonvopera
the inner end 19 of the probe exposed to the inside of the
tion of the TR tube when a ‘discharge cannot be initiated.
An attenuating protective mechanism has ‘been incorpo
envelope adjacent one ‘of the plate members 7. An ioniz
a'ble gaseous atmosphere of a suitable gas such as helium,
rated in the TR tube. This mechanism is referred to as
a “shutter” in accordance with US. Patent 2,734,171, 30 argon or hydrogen with a small percentage of water vapor
is provided within the envelope at a reduced pressure of
issued February 7, 1956 to Harold Heins and assigned to
a few millimeters of mercury.
the iassignee of the present invention. The mechanism
Pursuant to the teachings of the present invention, the
disclosed provides a metallic shorting member within a
novel attenuating mechanism is introduced into the tube
resonant element of the TR tube ‘and is electromechani
cally controlled. When the TR tube is inoperative, the 35 envelope through one of the narrow walls 3. The mecha
nism comprises an elongated shorting ‘bar member 20 sup
shorting member extends across the Waveguide path to
ported by a drive rod 21. A desirable material may be
contact another resonant element and thereby attenuate
'berrylium copper or other metals having a resiliency for
any undesired signals.
good contact and a slight ?ex-ing or bowing is preferred.
In accordance with advancements in the art, generators
FIG. 1 illustrates the mechanism in the open position with
of very high frequency signals have become available. At
the discharge gaps 13 and 14 uninhibited for normal TR
these frequencies waveguide dimensions are extremely
switch operation. The member 20 is touching the face
small and the aforementioned attenuating mechanisms
of the plate iris members 7 and is the end limit of travel
cannot be employed. An example may be the 15 to 17
toward the adjacent narrow waveguide wall 3.
kilomegacycle frequency range where the broad Wave
FIG. 2 illustrates the ‘closed position when the TR
guide wall is .702 inch and the narrow wall is .391 inch. 45
switch tube is inoperative. The shorting bar member 29
Since ‘generators have now been developed up to 75 kilo
contacts both pairs of conical electrodes to thereby effec
megacycles, a need exists for a protective attenuating
mechanism for TR switching devices at such high fre
quencies of transmission.
Accordingly, it is an object of the present invention to
provide a gaseous discharge switching device having a
new and novel protective ‘attenuating mechanism.
In accordance with the present invention, a gas switch
tively short circuit the electrodes and attenuate any unde
sired signals entering the tube envelope. The bar 29
moves into the gaps 13 ‘and 14 from a direction transverse
to the axes of the gaps. To facilitate seating of the bar
member against the ‘convergent end of all the conical elec
trodes, a notch 22, visible in FIG. 1, may be desirable.
ing TR tube having conventional internal resonant ele
The attenuating mechanism is activated by electrome
ments is provided with metallic means extending parallel 55 chanical means 23 secured to the narrow waveguide wall
to the envelope broad walls. Movement of the metallic
3 by a collar member 24. A metallic core 25 of soft iron
means by conventional electromechanical means results
having an axial bore 26 houses an end of the rod 21. An
electrical coil 27 surrounds core 25 and is connected to
elements to attenuate by a value ‘of 40 db or better any
an appropriate voltage supply, such as 14 or 28 volts DC.
60
signals entering the tube. A feature of the invention re
by means of terminals 23 mounted ‘on an insulator 29
sides in the provision of ‘a new and novel means for pro
in simultaneous short circuiting of a plurality of resonant
with wires 30 extending from the ‘coil. The housing 31
encloses the aforementioned components. Armature 32
of a suitable material secured to rod 21 is urged forward
shorting of multiple resonant discharge gaps with single
electromechanical means at a saving in cost, as well as, :a 65 by spring 33 and upon energizing of the electromechanical
means the tension of the spring is overcome to move the
reduction in number of ‘external structures disclosed in
shorting member 29 to the open position. To avert dis
the aforementioned patent.
location of the armature 32 in moving between the open
Further objects, features and advantages will become
apparent after consideration of the following detailed 70 or closed positions, an anchor pin 34 may be provided
extending through an aperture in the armature.
speci?cation and appended drawing, in which:
In an experimental embodiment for use at a frequency
FIG. 1 is a perspective view of the embodiment of the
tecting a sensitive receiver in TR switching tubes having
small internal dimensions. An additional feature is the
3,092,791
4
3
wherein the dimensions necessitate conical electrodes hav
broad walls to de?ne plural discharge gaps, attenuating
ing a tip-of .015 inch or less, attenuations of 40 db or bet
ter were achieved. In the open position, the shorting bar
means including an elongatedmmetallic shorting .bar mem
ber adapted to simultaneously contact all the electrode
member appears to have a negligible effect on insertion
ends and being movable in a-plane approximately parallel
loss since the overall tube measured only .5 db insertion
loss.
to the bro-ad side walla-and» electromechanical means
mounted on one of saidnarrow'walls to control~move
ment of said shorting bar member.
3. A microwave switching-device according to claim 2
Hence, ‘while prior art protective mechanisms require
separate short circuiting means for each discharge gap,
there is disclosed a single means for‘achieving this pur
pose for a plurality of gaps. Further, a single electrome
chanical means will now activate an ‘attenuating mecha
wherein said shorting, bar member-is fabricated with a '
10
nism for protection of switching tubes from undesired
microwave frequency signals.
bowed con?guration.
4. A microwave switching deviceia'ccording-to claim 2
wherein said electrode ends are provided ' with means
adapted to ifa‘cilitate seating of the‘shorting bar member
While a specific illustrative embodiment has been de
upon contact therewith.
5. A microwave switching device comprising, an en
velope ?lled with an i-onizable atmosphere-under reduced
pressure, a resonant element disposed within said envelope
sense consonant with the spirit and scope of the invention
to de?ne a discharge gap, said discharge gap having van
vas de?ned in the appended claims.
'
axis taken in the direction of the discharge across the‘ gap,
What is claimed is:
1. A microwave switching device comprising a metallic 20 attenuating means for short ‘circuiting said discharge gap
by moving into the gap, from a direction approximately
envelope ?lled with-an ionizable atmosphere under re
transverse to the axis of said discharge gap, and an electro
.duced pressure, resonant elements including plural op
mechanical means cooperating with and controlling the
posed conical electrode structures spaced within said en
movement of said attenuating means.
velope to de?ne plural discharge gaps having axes in the
direction of the discharge across :the gaps, attenuating 25
References Cited inthe ?le of this patent
means including a metallic shorting bar member adapted
to simultaneously contact a plurality of said electrode
UNITED STATES PATENTS
structures. by moving into the gap from a‘ direction trans
Heins ________________ __ Feb. 7, 1956
scribed above, it is intended that all matter appearing
herein and shown in the drawing be interpreted in a broad
verse to the axes of said gaps, and electromechanical
means to control movement of said shorting 1bar member. 30
2. A microwave switching device ‘comprising a rectan
gular waveguide envelope having parallel brood and nar
row walls and containing an ionizable atmosphere under
reduced pressure, plural spaced. resonant conical electrodes
having opposed ‘convergent ends extending ?rom opposite
2,734,174
2,816,272
Braden ______________ __ Dec. 10, 1957
OTHER REFERENCES
“Design and Development of- Shutter and TR-Shutter
Tubes,” Bom-ac Laboratories pamphlet,’ FIGS; 4 and- 5 re
Received US. Patent Oi?ce March 18,1955.
35 ferred to.
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