An electron deflection device responsive to an electrical input signal for producing an output signal includes a focusing array for producing a collimated electron beam input ribbon in the direction of a propagation axis, the input ribbon being elongated along an array axis perpendicular to the propagation axis, and being relatively thin along a deflection axis perpendicular to the array axis and to the propagation axis. The focusing array is preferably a linear array of gated cold cathode units with lens electrodes. The deflection device further includes first and second electrically conductive deflector faces, forming a deflection region therebetween and being disposed so that the propagation-axis passes through the deflection region. The deflection device further includes means responsive to the input signal for applying time varying potentials to the deflector faces so as to produce a modulated electric field in the deflection region for deflecting the input ribbon over the course of a temporal deflection cycle to produce a continuously modulated output ribbon. The deflection device further includes an anode section responsive to the continuously modulated output ribbon for producing an output signal. The output signal can be in the form of an electrical output signal or a chopped output ribbon suitable for input to a high power amplifier, such as a klystron, klystrode, traveling wave tube, distributed amplifier or a gigatron, or to a free electron laser.

FIELD OF THE INVENTION 
The present invention relates to electron beam deflection devices, and more 
particularly to medium power vacuum deflection amplifiers and to cathodes 
for production of chopped electron ribbons for power amplifiers in the 
microwave and millimeter-wave range. 
DESCRIPTION OF THE RELATED ART 
Deflection control or modulation of electron beams produced by thermionic 
emission was suggested almost half a century ago. See, Karl R. 
Spangenberg, "Vacuum Tubes," McGraw-Hill, 1948, .sctn.20.11, pages 
727-728. However, it was recognized then that such a design had severe 
shortcomings. Thermionic cathodes do not provide sufficiently high 
current. Thermionic cathodes have a large velocity spread, thus distorting 
the response. Other vacuum tube deflector designs which have been proposed 
are large, precluding efficient operation at high frequency. Some designs 
require the use of high anode potentials, thereby reducing the device 
efficiency. 
Cold cathode units now provide for electron beams with higher current 
density and with lower energy spread than thermionic cathodes. However, 
previously proposed deflection amplifiers using cold cathodes are 
inefficient at high frequencies because of their large size, high 
capacitance, large emittance, high anode voltage, or physical beam 
interception. Previously proposed designs also fail to provide for high 
gain over a wide bandwidth or else they are not suitable for use in 
integrated circuits. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a medium power vacuum 
deflection amplifier utilizing a high current density, low voltage 
electron beam produced by cold cathode units. 
Another object of the invention is to provide a medium power vacuum 
deflection amplifier utilizing a high current density, low voltage 
electron beam produced by cold cathode units, which deflection amplifier 
is suitable for use at frequencies as high as 40 gigahertz (GHz). 
A further object of the invention is to provide a medium power vacuum 
deflection amplifier utilizing a high current density, low voltage 
electron beam produced by cold cathode units, which deflection amplifier 
has high gain over a wide bandwidth at high frequencies. 
A still further object of the invention is to provide a medium power vacuum 
deflection amplifier device utilizing a high current density, low voltage 
electron beam produced by cold cathode units, which deflection amplifier 
is an integrated device suitable for use in integrated circuits. 
It is also an object of the invention to provide a medium power vacuum 
deflection modulator utilizing a high current density, low voltage 
electron beam produced by cold cathode units, which modulator produces a 
prebunched electron beam suitable for input to a high power amplifier, 
such as a klystron, traveling wave tube, or distributed amplifier for use 
at frequencies as high as 80 GHz. 
These and other objectives are achieved by an electron deflection device 
responsive to an electrical input signal for producing an output signal. 
The deflection device includes a focusing array for producing a collimated 
electron beam input ribbon in the direction of a propagation axis, the 
input ribbon being elongated along an array axis perpendicular to the 
propagation axis, and being relatively thin along a deflection axis 
perpendicular to the array axis and to the propagation axis. The focusing 
array is preferably a linear array of gated cold cathode units with lens 
electrodes. The deflection device further includes first and second 
electrically conductive deflector faces, forming a deflection region 
therebetween and being disposed so that the propagation-axis passes 
through the deflection region. The deflection device further includes 
means responsive to the input signal for applying time varying potentials 
to the deflector faces so as to produce a modulated electric field in the 
deflection region for deflecting the input ribbon over the course of a 
temporal deflection cycle to produce a continuously modulated output 
ribbon. The deflection device further includes an anode section responsive 
to the continuously modulated output ribbon for producing an output 
signal. 
The output signal can be in the form of an electrical output signal or a 
chopped output ribbon suitable for input to a high power amplifier, such 
as a klystron, klystrode, traveling wave tube, distributed amplifier or a 
gigatron, or to a free electron laser.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, an electron deflection device 100 responsive 
to an electrical input signal I.sub.s (not shown) for producing an output 
signal U.sub.s (not shown) is shown in FIG. 1. 
The device 100 includes a focusing array 200 for producing a collimated 
electron beam input ribbon R.sub.i (not shown). The device 100 further 
includes a deflection section 300 integrated with the focusing array 200, 
the deflection section 300 being responsive to the input signal I.sub.s 
for deflecting the input ribbon R.sub.i to produce a continuously 
modulated output ribbon R.sub.cm (not shown) having a time-varying path. 
The device 100 further includes an anode section 400 responsive to the 
continuously modulated output ribbon R.sub.cm for producing the output 
signal U.sub.s. The device 100 is preferably encapsulated in a vacuum on 
the order of 10.sup.-6 -10.sup.-9 Torr. 
The focusing array 200 is a linear array of a plurality of cold cathode 
units 210 disposed along a y-axis. The focusing array 200 produces an 
input ribbon R.sub.i propagating in the z-direction, that is, upwards as 
shown in FIG. 1. The x and y axes are orthogonal with respect to the 
z-direction. The input ribbon R.sub.i is elongated along the y-axis and, 
as discussed below, is relatively thin in the x-direction. 
The focusing array 200 produces a highly collimated input ribbon R.sub.i. 
The trajectories of all electrons in a perfectly collimated beam are 
parallel to each other. A highly collimated beam has low normalized 
emittance. As defined in Tang, C. M. et al., "Field-Emission Arrays--a 
Potentially Bright Source," in "Nuclear Instruments and Methods in Physics 
Research" A318 (1992) 353-357, North Holland, which is incorporated herein 
by reference, and as discussed further below, normalized emittance 
.epsilon..sub.n is determined with reference to a phase space emittance 
diagram, such as the diagram shown in FIG. 2. The abscissa of FIG. 2 is 
displacement parallel to the x-axis, and the ordinate is 
(.beta..multidot..gamma..gamma..multidot..theta.) which is the product of 
the relativistic factors .beta., .gamma. and .theta., where 
##EQU1## 
c is the speed of light in vacuo, and the vector v having components 
v.sub.x, v.sub.y, and v.sub.z is the velocity of electrons emitted from 
the focusing array 200. 
The emittance diagram shown in FIG. 2 is determined for a cold cathode unit 
210 with respect to a fixed z-displacement (FIG. 1). As the y-displacement 
(FIG. 1) is varied for a fixed x-displacement (FIG. 1), the product 
.beta..multidot..gamma..multidot..theta. for each electron falls within a 
range as shown by the line segment r. The product 
.beta..multidot..gamma..multidot..theta. stays within the range r as the 
y-displacement is increased, until it reaches a sharp boundary past which 
there is no further electron emission. The area occupied by the electrons 
in (x, .beta..multidot..gamma..multidot..theta.) phase space on this 
diagram, that is, the area of the shaded propeller-type shape in FIG. 2, 
is the normalized emittance .epsilon..sub.n in the x-direction. The 
normalized emittance .epsilon..sub.n (the area) does not vary in the 
paraxial limit as the z-displacement is varied. 
For nonrelativistic propagation of electrons, 
.beta..multidot..gamma..theta..apprxeq.v.sub.x /c. For a given beam 
x-thickness, the more collimated the input ribbon R.sub.i, the smaller the 
maximum value for .beta..multidot..gamma..multidot..theta., and therefore, 
the more horizontal the shaded shape. A perfectly collimated beam has zero 
normalized emittance. For purposes of this invention, the normalized 
emittance in the x-direction associated with the focusing array 200 is on 
the order of a few 10.sup.-3 .pi. millimeter-milliradians (mm-mrad). 
Normalized emittance of at most 10*10.sup.-3 .pi. mm-mrad is considered 
sufficiently low, but normalized emittance of at most 2*10.sup.-3 .pi. 
mm-mrad is preferable, and normalized emittance of 10.sup.-3 .pi. mm-mrad 
is most preferable. Cold cathode units 210 with normalized emittance as 
high as 1000*10.sup.-3 .pi. mm-mrad (which is less than that obtained from 
most thermionic cathodes) could also be used, but yield lower 
gain-bandwidth product and are not as effective at frequencies above 1 
GHz. 
Collimation is a measure of the extent to which the input ribbon R.sub.i 
approaches a perfectly collimated beam, that is, an electron ribbon in 
which the electron trajectories are parallel to each other. As discussed 
earlier, a highly collimated beam has low normalized emittance. An input 
ribbon R.sub.i with normalized emittance .epsilon..sub.n of 10.sup.-3 .pi. 
mm-mrad and an x-thickness of 4 micrometers (.mu.m) would be considered 
highly collimated if it had a collimation angle=arctan(v.sub.x /v.sub.z) 
of 5.degree.. Highly collimated beams are capable of being focused to a 
very thin sheet within this device, thereby enhancing the performance of 
this deflection device. In fact, the electron deflection device of the 
present invention serves to keep the electron beam focused to a very thin 
sheet within this device. 
Further desirable specifications of the input ribbon R.sub.i produced by 
the focusing array 200 are that it have energy on the order of tens of 
electron volts (eV), preferably below 200 eV and most preferably below 50 
eV, with energy spread under 0.2 eV, and that the input ribbon have 
thickness in the x-direction of under about 200 .mu.m and most preferably 
under about 10 .mu.m. Furthermore, the input ribbon R.sub.i has current 
density J between 20 and 1000 Ampere/cm.sup.2 (A/cm.sup.2), preferably on 
the higher end of this range. In other words, the focusing array 200 
preferably produces a high current density input ribbon. Although not 
absolutely required for the practice of this invention, the total current 
emitted from the focusing array 200 may be on the order of 1 A. The cold 
cathode units 210 may be spaced apart in the y-direction by as little as 2 
.mu.m. Each cold cathode unit 210 produces a beamlet with up to about 100 
micro Amperes (.mu.A) current. 
Referring now to FIG. 3, an exemplary focusing array 200 is a vacuum 
cone-type focusing array. This invention may also be practiced using other 
cold emitter designs known to persons of ordinary skill in the art, such 
as one dimensional focusing array wedges (with or without lens electrodes) 
and one dimensional focusing array edges (with or without lens 
electrodes). 
The focusing array 200 includes a plurality of cold cathode units 210 
regularly spaced along the y-axis. Each cold cathode unit 210 emits an 
electron beamlet (not shown) from the tip 215 of an emitter cone 220 which 
is mounted on a conducting substrate 230 and is therefore at the same 
voltage as the substrate 230. The substrate 230 is common to all the cold 
cathode units 210. The plurality of beamlets emitted by the plurality of 
cold cathode units 210 constitutes the input ribbon R.sub.i. 
A gate 240 for extracting the electron beamlet is positioned apart from the 
emitter cone 220. A first lens electrode 250 for focusing the electron 
beamlet is positioned above the gate 240. The first lens electrode 250 
provides beam collimation, i.e. the voltage gradient between the gate 240 
and the first lens electrode 250 results in focusing of the beamlet. The 
gate 240 and first lens electrode 250 can be circular lenses, linear 
lenses, or other appropriate designs. The gate 240 need not be a lens. The 
gate 240 is mounted on an insulating spacer 260 which spacer 260 is thus 
between the substrate 230 and the gate 240, and the first lens electrode 
250 is mounted on an insulating spacer 270 on the gate 240, which spacer 
270 is thus between the gate 240 and the first lens electrode 250. The 
insulating spacers 260 and 270 are typically silicon dioxide (SiO.sub.2). 
Optionally, one or more additional lens electrodes 280 (FIG. 5) may be 
positioned above the first lens electrode 250 to further focus the 
beamlet. An example of a double lens electrode design is discussed further 
below. 
The tip 215 has a very small radius of curvature, for example, on the order 
of 185 .ANG. or less. Upon application of a relatively low electric 
potential drop between the gate 240 and the emitter cone 220, a high 
electric field is produced at the tip 215, causing electron emission from 
the tip 215. The voltage of the tip 215, which is the same as the voltage 
of the substrate 230, is considered the reference voltage herein. The 
emitter cone 220 need not be heated as thermionic cathodes must be, and in 
fact it may be operated at room temperature. Electrons are continuously 
extracted from the emitter cone 220 by application of a constant positive 
dc voltage to the gate 240, which is positioned near the tip 215. The 
focusing array 200 is designed so that the emitted electrons do not 
intercept either of the insulator spacers 260 and 270. As is known in the 
art, cold cathode units 210 with extraction gates 240 are capable of 
emitting electron beams independently of any electric fields external to 
the cold cathode unit 210, if a constant dc potential drop is applied 
between the gate 240 and the emitter cone 220. 
Referring now to FIG. 4, an example of a single lens electrode design for 
the focusing array 200 of FIG. 1 and 3 is shown. In this design, the gate 
240 and the first lens electrode 250 are self-aligned. This example is 
referred to as having a sidewall lens. The generally horizontal and 
vertical lines of FIG. 4 depict electron trajectories and equipotentials, 
respectively, as determined by computer simulation. These trajectories and 
potentials are shown in cross-section through the x-z plane (FIG. 1) with 
the y-displacement selected so the x-z plane passes through the tip 215. 
The origin of the x-z plane is selected so as to coincide with the tip 
215. 
In this example, the surface of the emitter cone 220 forms an angle of 
35.degree. with respect to the vertical. Gate voltage V.sub.g =100 V is 
applied to the gate 240, and the emitter cone 220 is considered ground, 
i.e., the reference voltage. V.sub.g is optimally between 90 V and 130 V. 
A first voltage, V.sub.1 =3 V, optimally 3-9 V, is applied to the first 
lens electrode 250, and so the input ribbon R.sub.i has 3 eV energy. The 
gate has thickness t.sub.g of 0.4 .mu.m and the tip 215 is t.sub.tip =0.15 
.mu.m above the bottom of the gate 240. The bottom of the first lens 
electrode 250 is t.sub.g,1 =0.5 .mu.m above the top of the gate 240. The 
minimum diameters d.sub.g and d.sub.1 of the openings for the gate 240 and 
the first lens electrode 250 are 1.3 .mu.m and 1.8 .mu.m, respectively. 
The thickness of the first lens electrode 250 is t.sub.1 =2.6.mu.m, which 
is related to d.sub.1 as t.sub.1 =1.44*d.sub.1. As shown in FIG. 4, the 
inside edge of the gate 240 and the first lens electrode 250 are each at 
an opening angle .phi.=15.degree. with respect to the z-axis, and these 
inside edges fall along the same conic section. As further shown in FIG. 
4, the inside opening of the lens electrode 250 is tapered and becomes 
larger as the distance from the tip 215 of the tip 215 increases. The 
distance between the gate 240 and the substrate 230 is t.sub.s,g 0.7 
.mu.m. The thickness t.sub.1 of the first lens electrode 250 (2.6 .mu.m) 
is considerably greater than the gate thickness t.sub.g (0.4 .mu.m) and 
than the distance between the gate 240 and the first lens electrode 250 
(0.5 .mu.m). As described further below, an accelerating electric field of 
2 V/.mu.m, optimally 2-10 V/.mu.m, is applied in the z-direction beyond 
the first lens electrode 250. 
Further design considerations of this sidewall lens focusing array 200 
shown in FIG. 3 are shown in the following TABLE 1. 
TABLE 1 
______________________________________ 
Variable Range 
______________________________________ 
d.sub.g (.mu.m) 0.08-2.5 
d.sub.1 (.mu.m) 0.08-2.5 
t.sub.tip (.mu.m) 
-0.1 .ltoreq. t.sub.tip .ltoreq. t.sub.g + 0.2 
t.sub.g (.mu.m) (thickness decreases 
0.1-1.0 
as diameter decreases from 
calculated value for gate 
diameter d.sub.g less than 1.0 .mu.m) 
t.sub.1 /d.sub.1 (.mu.m/.mu.m) 
0.75-3.0 
V.sub.g (Volts) 25-250 
V.sub.1 (Volts) 1-20 
(V.sub.g -V.sub.1)/t.sub.g,l (V/.mu.m) 
(V.sub.g -V.sub.1)/t.sub.g,l &lt; V.sub.270, where V.sub.270 
is 
the breakdown voltage of the 
insulating spacer 270. For 
SiO.sub.2 , the typical breakdown 
voltage is V.sub.270 = 250-400 V/.mu.m. 
V.sub.g /t.sub.s,g (V/.mu.m) 
V.sub.g /t.sub.s,g &lt; V.sub.260, where V.sub.260 is the 
breakdown voltage of the insu- 
lating spacer 260. For SiO.sub.2, 
the typical breakdown voltage 
is V.sub.260 = 250-400 V/.mu.m. 
.phi. (lens and gate opening 
0-45 
angle) (.degree.) 
accelerating electric field in 
0.1-300 
the z-direction beyond the 
first lens electrode 250 
(V/.mu.m) 
______________________________________ 
A sidewall lens focusing array 200 can be non-aligned as well as 
self-aligned, although the latter is preferable in terms of production. 
Manufacture of a self-aligned focusing array 200 generally takes fewer 
fabrication masks than manufacture of a non-aligned focusing array 200. 
Referring now to FIG. 5, an example of a double lens electrode design for 
the focusing array 200 is shown. In addition to having a first lens 
electrode 250, this structure also has a second lens electrode 280 
positioned above the first lens electrode 250, that is, further from the 
substrate 230. The generally horizontal and vertical lines of FIG. 5 
depict electron trajectories and equipotentials, respectively, as 
determined by computer simulation. These trajectories and potentials are 
shown in cross-section through the x-z plane with the y-displacement 
selected so that the x-z plane passes through the tip 215. The origin of 
the x-z plane is selected so as to coincide with the tip 215. The optimal 
and preferred specification ranges for this design are shown in the 
following TABLE 2. 
TABLE 2 
______________________________________ 
Most 
Preferred 
Variable Range Preferred Range 
______________________________________ 
d.sub.g (.mu.m) 
1.1 0.08-2.5 
d.sub.1 (.mu.m) 
3.4 0.08-10.0 
d.sub.2 (.mu.m): minimum open- 
5.5 0.08-10.0 
ing of the second lens 
electrode 280 
t.sub.tip (.mu.m) 
0.0 t.sub.tip .ltoreq. t.sub.g 
t.sub.g (.mu.m) 
0.7 0.45 .ltoreq. (t.sub.g -t.sub.tip)/d.sub.g 
.ltoreq. 1 
t.sub.1 (.mu.m) 
0.4 t.sub.1 /d.sub.1 &lt; 0. 2 
t.sub.2 (.mu.m): thickness of 
0.4 t.sub.2 /d.sub.2 &lt; 2.0 
the second lens elec- 
trode 280 
V.sub.g (Volts) 
90-130 25-250 
V.sub.1 (Volts) 
895 1 &lt;&lt; V.sub.1 /V.sub.g and (V.sub.1 - 
V.sub.g)/t.sub.g,1 is as large as 
possible 
V.sub.2 (Volts): Voltage of 
50 0 .ltoreq. V.sub.2 .ltoreq. 100; V.sub.2 &lt; 
V.sub.1 
the second lens elec- 
trode 280 
t.sub.g,1 (.mu.m) 
2.5 (V.sub.1 -V.sub.5)/t.sub.g, 1 &lt; V.sub.270, where 
V.sub.270 is the breakdown 
voltage of the insulat- 
ing spacer 270. For 
SiO.sub.2, the typical 
breakdown voltage is 
V.sub.270 = 250-400 V/.mu.m. 
t.sub.1,2 (.mu.m): distance 
2.47 (V.sub.1 -V.sub.2)/t.sub.1,2 &lt; V.sub.1,2, where 
between first lens V.sub.1,2 is the breakdown 
electrode 250 and voltage of the insulat- 
second lens electrode ing spacer between the 
280 first and second lens 
electrodes 250 and 280. 
For SiO.sub.2, the typical 
breakdown voltage is 
V.sub.1,2 = 250-400 V/.mu.m. 
t.sub.s,g (.mu.m) 
0.7 V.sub.g /T.sub.s,g &lt; V.sub.260, where V.sub.260 
is the breakdown volt- 
age of the insulating 
spacer 260. For SiO.sub.2, 
the typical breakdown 
voltage is V.sub.260 = 
250-400 V/.mu.m. 
.phi..sub.g (.degree.): gate opening 
22.5 0-45 
angle 
.phi..sub.1, .phi..sub.2 (.degree.): opening 
0 0-45 
angles for lens elec- 
trodes 250 and 280 
accelerating electric 
0 0-300 
field in the z-direc- 
tion beyond the second 
lens electrode 280 
(V/.mu.m) 
______________________________________ 
The configuration of the focussing array 200 of FIG. 1 is not necessarily 
limited to the embodiments shown in FIGS. 3, 4 or 5 so long as the 
focussing array 200 has the above-described properties. 
Referring now to FIGS. 6 and 1, the deflection section 300 of an electron 
deflection device 100 includes first and second electrically conductive 
deflector faces 310 and 320, respectively disposed symmetrically with 
respect to the y-axis so as to face inward towards the y-axis. The first 
and second deflector faces 310 and 320 are supported on first and second 
deflector plates 330 and 340, respectively. An input electrical circuit 
(not shown) responsive to the electrical input signal I.sub.s is connected 
to the deflector plates 330 and 340 for applying electric potentials 
.phi..sub.A and .phi..sub.B to the first and second deflector faces 310 
and 320, respectively. 
The deflector faces 310 and 320 form a vacuum deflection region 350 
therebetween, and are disposed so that the z-axis passes through the 
deflection region. As a result of the input electrical circuit's 
application of potentials .phi..sub.A and .phi..sub.B to the deflector 
faces 310 and 320, respectively, the deflection section 300 produces an 
electric field E in the deflection region 350. 
The electrical input circuit provides time varying potentials .phi..sub.A 
and .phi..sub.B so that the potential difference .phi..sub.A -.phi..sub.B, 
i.e. the modulation voltage, and therefore the x-component E.sub.x of the 
electric field E in the deflection region 350, is proportional to the ac 
component of the input signal I.sub.s. The maximum amplitude of the 
modulation voltage, i.e. the variation .DELTA.V.sub.m of the modulation 
voltage, is typically on the order of a tenth of a Volt to a few Volts, 
and preferably less than 4 Volts. The peak of the electric field component 
E.sub.x is typically in the range 5-500 mV/.mu.m. This small modulation 
voltage makes higher frequency operation and higher gain feasible. 
The dc values of the applied potentials .phi..sub.A and .phi..sub.B can 
provide an appropriate field between the focusing array 200 and the 
deflector sector, such as the accelerating field referred to earlier. 
It is preferable that the potentials .phi..sub.A and .phi..sub.B be applied 
to the deflector faces 330 and 340, respectively, so that the potentials 
propagate in the x-direction, but they can also be applied so as to 
propagate in the y-direction. 
The modulated electric field E transversely deflects the input ribbon 
R.sub.i in the x-direction to produce a continuously modulated output 
ribbon R.sub.cm. Although the input ribbon R.sub.i is propagated with 
constant velocity in the z-direction, the deflection section 300 
transversely deflects the input ribbon R.sub.i to produce the continuously 
modulated output ribbon R.sub.cm propagating in time-varying directions. 
The deflection section 300 provides a modulated x-component of the beam 
velocity of ribbon R.sub.cm. 
The specifications of the deflection section 300 are selected so as to 
satisfy the above conditions. In order to effectively deflect the input 
ribbon R.sub.i in the x-direction, the deflector faces 310 and 320 should 
be at least as long in the y-direction (perpendicular to the x-z plane) as 
the input ribbon R.sub.i is. This y-dimension is approximately the size of 
the focusing array 200 in the y-direction. 
In order to effectively modulate the input ribbon R.sub.i at high 
frequencies, the transit time L.sub.z /v.sub.z of electrons passing 
through the deflection region 350 should be short with respect to l/f, 
where L.sub.z is the z-dimension of the deflector faces 320 and 340, 
v.sub.z as stated earlier, is the z-component of the electron velocity, 
and f is the frequency of the ac component of the input signal I.sub.s. 
The z-dimension L.sub.z of the deflector faces 310 and 320 is typically on 
the order of tens of .mu.m. The factor .theta.=.omega.L.sub.z /v.sub.z is 
a normalized measure of the z-dimension of the deflector faces 320 and 
340, where .omega.=2.pi.f is the angular frequency of the input signal 
I.sub.s. The factor .theta. is preferably in the range 
0&lt;.theta..ltoreq..pi.. 
The gap in the x-direction between deflector faces 310 and 320, i.e., the 
x-size of the deflection region 350, should be as small as possible and 
yet large enough to accommodate the width of the input ribbon R.sub.i 
(which is preferably under 200 .mu.m and most preferably under 10 .mu.m) 
and provide room for deflection so that the input ribbon R.sub.i does not 
physically intercept any structural part of the deflection section 300. A 
small gap between deflector faces 310 and 320 maximizes the electric field 
component E.sub.x in the deflection region 350 so as to maximize 
deflection of the input ribbon R.sub.i and thereby maximize the amplifier 
gain. 
Space charge effects become significant as the line current density 
.DELTA.I/.DELTA.y of the input ribbon R.sub.i increases, based on the 
following relation: 
##EQU2## 
where e is the absolute value of the elementary electron charge, m.sub.e 
is the electron mass, .epsilon..sub.0 is the free space permeability, 
eV.sub.i the electron energy in units of electron Volts (eV), D is the gap 
between deflectors 330 and 340, and the electron beam is located in the 
center between the deflectors 330 and 340. For eV.sub.i =10 eV, D=8 .mu.m, 
and the average potential of deflectors 330 and 340 is 10 V, then the 
space charge effect becomes important as the line current density exceeds 
10 .mu.A/.mu.m, and becomes detrimental as the line current density 
approaches 30 .mu.A/.mu.m. Therefore, the focusing array 200 produces an 
input ribbon having line current density as large as possible but less 
than (.DELTA.I/.DELTA.y).sub.max as specified in the above relation. 
A feature of the electron deflection device 100 is that the input ribbon 
R.sub.i produced by the focusing array 200 is focused to a very thin 
sheet, and the continuously modulated output ribbon R.sub.cm produced by 
the deflection section 300 remains focused to a very thin sheet as far as 
the anode section 400. 
The anode section 400 responsive to the continuously modulated output 
ribbon R.sub.cm for producing the output signal U.sub.s includes a first 
anode 410 and a second anode 420 positioned and designed so that the 
electron beam R.sub.cm intercepts the first anode 410 during part of the 
deflection cycle and the second anode 420 during part of the deflection 
cycle. The first anode 410 is loaded with potential .phi..sub.1 and 
impedance Z.sub.1, and the second anode 420 is loaded with potential 
.phi..sub.2 and impedance Z.sub.2. As a result of the electron beam 
R.sub.cm intercepting the anodes 410 and 420, the anode section 400 
produces first and second electrical output signals U.sub.1 and U.sub.2, 
respectively. These signals U.sub.1 and U.sub.2 can be selectively 
combined to constitute the output signal U.sub.s. 
The first and second anodes 410 and 420 are each disposed in the path of 
the continuously modulated output ribbon R.sub.cm. The first anode 410 is 
disposed closer to the deflection section 300 than the second anode 420. 
The first anode 410 is loaded with potential .phi..sub.1 selected so that 
it is on an equipotential surface with respect to the second anode 420. 
For example, if the second anode 420 were loaded at .phi..sub.2 =150 V and 
were disposed 85 .mu.m from a deflection section 300 having a dc bias of 
10 V, then a first anode 410 disposed 45 .mu.m from the deflection section 
300 would be loaded at 
##EQU3## 
The applied potentials .phi..sub.1 and .phi..sub.2 are further selected so 
that .phi..sub.A, .phi..sub.B, &lt;&lt;.phi..sub.1 -I.sub.1 .multidot.Z.sub.1 
and .phi..sub.1 .apprxeq.&lt;.phi..sub.2 -I.sub.2 .multidot.Z.sub.2, are the 
peak total current to the first and second anodes 410 and 420, 
respectively. These conditions minimize anode loading problems caused by 
electron repulsion from the anodes due to voltage depression resulting 
from output current I.sub.1 or I.sub.2. 
The second anode 420 can be a single plate. The first anode 410 provides a 
slit 430 for passage of the continuously modulated output ribbon R.sub.cm 
to pass therethrough during part of the deflection cycle. As shown in FIG. 
6, the first anode 410 includes sections 440 and 450 with the slit 430 
therebetween, asymmetrically positioned and designed so that the 
continuously modulated output ribbon R.sub.cm intercepts section 440 
during part of the deflection cycle and does not intercept section 450 
during any part of the deflection cycle. Sections 440 and 450 can be 
separate plates or different sections of a single plate containing a slit 
430. Section 450 serves to balance the electric field near the anode 
section 400 so that equipotential surfaces are generally perpendicular to 
the path of the continuously modulated output ribbon R.sub.cm. 
Referring now to FIG. 7, a configuration of anode section 400 is shown in 
which the continuously modulated output ribbon R.sub.cm strikes the first 
anode 410 during at least two separate parts of the deflection cycle and 
passes through the slit 430 during another part of the deflection cycle. 
Sections 440 and 450 can be symmetrically disposed about the path of the 
continuously modulated output ribbon R.sub.cm. Just as in the 
configuration shown in FIG. 6, sections 440 and 450 can be separate plates 
or different sections of a single plate containing a slit 430. The output 
signal U.sub.s for such a configuration has a frequency twice that of the 
input signal I.sub.s frequency. The load parameters .phi..sub.1, 
.phi..sub.2, Z.sub.1 and Z.sub.2 satisfy the same conditions as the device 
shown in FIG. 6. 
It is not necessary that the first anode 410 be asymmetric as shown in FIG. 
6 in order to produce an output signal U.sub.s of the same frequency as 
the input signal I.sub.s, or that the first anode 410 be symmetric as 
shown in FIG. 7 in order to produce an output signal U.sub.s of twice the 
input signal I.sub.s frequency. The same results could be achieved by 
applying a bias between the first and second deflector faces 310 and 320 
and shifting the slit 430, or by using some combination of bias and slit 
430 position. 
A person of ordinary skill in the art may readily design an anode section 
400 for use in an electron deflection device 100 of the present invention 
so as to be responsive to the continuously modulated output ribbon 
R.sub.cm for producing an output signal U.sub.s. For example, rather than 
loading the first and second anodes 410 and 420 with potentials 
.phi..sub.1 and .phi..sub.1 and impedances Z.sub.1 and Z.sub.2, 
respectively, inductive bias chokes (not used) could be used. As another 
example, anode sections 440 and 450 could be loaded with different 
impedances. 
As a further example, the push-pull configuration of U.S. Pat. No. 
2,553,753 to Adler, designed for use with a thermionic emitter, may be 
readily adapted for use with a cold cathode unit 200 (FIGS. 1, 3). 
Referring now to FIG. 8, an acceleration voltage, for example 90 V, is 
applied to an accelerating electrode 460, which includes slots 462 and 466 
for passage of the continuously modulated output ribbon R.sub.cm 
therethrough. A beam splitting element 470 series to divide the projected 
beam R.sub.cm into two portions so that the ribbon R.sub.cm intercepts the 
first anode 410 during part of the deflection cycle and the second anode 
420 during another part of the deflection cycle. The first anode 410 and 
the second anode 420 are connected across a primary winding 482 of a 
center-tap transformer 480, the center tap being held at the accelerating 
voltage. A secondary winding 484 of the transformer 480 produces the 
output signal U.sub.s. 
The above designed electron deflection device 100 may be used as in 
amplifier in the microwave range. Other uses may be readily determined by 
a person of ordinary skill in the art. For example, it may also be used as 
an oscillator in the microwave range. When so used, the factor 
.theta.=.omega.L.sub.z /v.sub.z is preferably in the range 
2.pi.&lt;.theta..ltoreq.2.86.pi., and most preferably .theta.=2.5.pi.. 
Referring now to FIGS. 9 and 1, an electron deflection device 100 is shown 
which is suitable for use as a modulator or beam source to produce a 
chopped output ribbon U.sub.s. The output ribbon is suitable for input to 
a high power amplifier, such as a klystron, klystrode, traveling wave 
tube, distributed amplifier or a gigatron, or to a free electron laser. 
The anode section 400 of the device shown in FIG. 9 comprises a first anode 
410 comparable to the first anode 410 of the deflection amplifier shown in 
FIG. 6 and described earlier. The first anode 410 is positioned and 
designed so that the electron beam R.sub.cm intercepts the first anode 410 
during part of the deflection cycle. The first anode 410 provides a slit 
430 for passage of the continuously modulated output ribbon R.sub.cm 
therethrough during another part of the deflection cycle, thereby 
producing the output ribbon U.sub.s. The first anode 410 includes sections 
440 and 450 with the slit 430 therebetween, asymmetrically positioned and 
designed so that the continuously modulated output ribbon R.sub.cm 
intercepts section 440 during part of the deflection cycle and does not 
intercept section 450 during any part of the deflection cycle. Section 450 
serves to balance the electric field near the anode section 400 so that 
equipotential surfaces are generally perpendicular to the path of the 
continuously modulated output ribbon R.sub.cm. 
Referring now to FIGS. 10 and 1, an electron deflection device 100 is shown 
which also is suitable for use as a modulator or beam source to produce a 
chopped output ribbon U.sub.s. The anode section 400 comprises a first 
anode 410 comparable to the first anode 410 of the deflection amplifier 
shown in FIG. 7 and described earlier. The anode section 400 is designed 
so that the continuously modulated output ribbon R.sub.cm strikes the 
first anode 410 during at least two separate parts of the deflection 
cycle. Just as in the configuration shown in FIG. 9, the first anode 410 
provides a slit 430 for passage of the continuously modulated output 
ribbon R.sub.cm therethrough during part of the deflection cycle, thereby 
producing the output ribbon U.sub.s. The output ribbon U.sub.s for such a 
configuration has a frequency double the frequency of the input signal 
I.sub.s. Sections 440 and 450 can be symmetrically disposed about the path 
of the continuously modulated output ribbon R.sub.cm. 
A simulated example of this configuration uses a drive frequency of 40 GHz 
to produce an 80 GHz prebunched chopped output ribbon U.sub.s. In this 
example, the gap 430 of the first anode 410 is 10 .mu.m. The first anode 
410 is 45 .mu.m from the deflector section 430 and is at potential 
.phi..sub.1 =90 V. A modulation voltage variation of .DELTA.V.sub.m =4 V 
is applied to an input ribbon R.sub.i having current of 7 mA. 
Referring now to FIG. 11, part of a multiple beam device is shown which is 
suitable for use as a deflection amplifier. This multiple beam device 
includes at least 2 units 100 comparable to the devices 100 as shown in 
FIGS. 1, 3 and 6. The at least two devices 100 are spaced apart in the 
x-direction and integrated as appropriate so that adjacent continuously 
modulated output ribbons R.sub.cm are deflected in opposite directions. 
For example, adjacent focusing arrays 200 may share a common substrate 
230, insulating spacers 260 and 270, and parts of the lens electrode 250. 
Adjacent deflection sections 300 may have a common deflector plate 340. 
Adjacent anode sections 400 may have a common second anode 420. The first 
anode 410 shown in FIG. 11 differs from the first anode 410 shown in FIG. 
6 in that adjacent first anodes 410 (FIG. 6) will have a total of two 
slits 430 and four sections 440 and 450 (FIG. 6), and can be combined to 
constitute a first anode 410 (FIG. 11) having one slit 430 and two 
sections 440 (FIG. 11). 
Another configuration for a multiple beam device which is suitable for use 
as a deflection amplifier also includes at least 2 units 100 comparable to 
the devices 100 as shown in FIGS. 1 and 3 and spaced apart in the 
x-direction. Unlike the configuration shown in FIG. 11, the adjacent 
devices 100 are integrated as appropriate so that adjacent continuously 
modulate output ribbons R.sub.cm are deflected in the same direction. Such 
a multiple beam device is essentially a combination of devices as shown in 
FIGS. 1, 3, and 6, 7 or 8. If it includes devices 100 comparable to those 
shown in FIGS. 1, 3 and 7, the output frequency can be double the input 
frequency. 
Multiple deflection devices suitable for use as a modulator or beam source 
for producing at least two chopped output ribbons U.sub.s include at least 
2 units 100 comparable to the devices 100 as shown in FIGS. 1, 3, 9 and 
10. The at least two devices 100 are spaced apart in the x-direction and 
integrated as appropriate so that adjacent continuously modulate output 
ribbons R.sub.cm are deflected in opposite directions. Just as shown in 
FIG. 11, adjacent focusing arrays 200 may share a common substrate 230, 
insulating spacers 260 and 270, and parts of the lens electrode 250. 
Adjacent deflection sections 300 may have a common deflector plate 340 and 
adjacent anode sections 400 may have common first anodes 410. If it 
includes devices 100 comparable to those shown in FIGS. 1, 3 and 10, the 
output frequency can be double the input frequency. 
Another design for multiple deflection devices suitable for use as a 
modulator or beam source for producing at least two chopped output ribbons 
U.sub.s includes at least 2 units 100 comparable to the devices 100 as 
shown in FIGS. 1, 3 and 9 or 10. The at least two devices 100 are spaced 
apart in the x-direction and integrated as appropriate so that adjacent 
continuously modulate output ribbons R.sub.cm are deflected in the same 
direction. 
The following results have been obtained from computer simulations of this 
invention using software MAGIC and EGUN2. MAGIC is available from Mission 
Research Corp., Newington, Va. 22122; EGUN is discussed in W. B. 
Herrmannsfeldt, "EGUN--An Electron Optics and Gun Design Program," SLAC 
Report 331 (1988). 
Using the configuration of FIG. 6 with an input ribbon having a current of 
14 mA and energy 10 eV, the required input power for each deflector is 
3.2*10.sup.-4 W while the output power is 2.45*10.sup.-3 W, yielding a 
power gain of 7.66. The gain bandwidth product is G.DELTA.f=2.2 GHz. 
For input ribbon having 2A current, and multiple units being connected 
together as discussed above as a multiple beam deflection amplifier, the 
gain bandwidth product is G.DELTA.f=300 GHz, and the power gain is 819. 
The device operates at an rf power efficiency of 15%. 
Further computer simulated examples also use the configuration shown in 
FIG. 6 and frequency 10 GHz, but have longer deflector faces 310 and 320 
in the z-direction as measured by the factor .theta.=.omega.L.sub.z 
/v.sub.z. In these examples, the line current density is 20 .mu.A/.mu.m, 
the input ribbon R.sub.i has width .delta.x=10 .mu.m and energy 34 eV, 
.DELTA.V.sub.m =0.24 V, short circuit current gain bandwidth product 
f.sub.T =60 GHz, and the gap between deflector faces 310 and 320 is D=20 
.mu.m. For .theta.=.pi., L.sub.z =170 .mu.m, .DELTA.V.sub.m =0.24 V, and 
f.sub.T =60 GHz. For .theta.=.pi./2, L.sub.z =85 .mu.m, .DELTA.V.sub.m 
=0.34 V, and f.sub.T =155 GHz. As .theta. approaches 0, f.sub.T approaches 
260 GHz. This result is further described in C. M. Tang, Y. Y. Lau, T. A. 
Swyden, "Deflection Microwave Amplifier with Field Emission Arrays," 
submitted to International Electronics Device Meeting '93, which paper is 
incorporated herein by reference. 
A simulation of 40 GHz amplification uses anode voltages of .phi..sub.1 =90 
V and .phi..sub.2 =120 V, modulation voltage variation .DELTA.V.sub.m =2 
V, input ribbon current 375 mA, and loads Z.sub.1 =Z.sub.2 =200.OMEGA.. 
The first and second anodes 410 and 420, are 30 .mu.m and 55 .mu.m, 
respectively, from the deflection section 300. The simulation shows that 
using multiple units of this configuration to obtain total input beam 
R.sub.i current of 375 mA provides gain bandwidth product of G.DELTA.f=165 
GHz and power gain of 24. The device operates at an rf power efficiency of 
24%. 
It is understood that many other changes and additional modifications of 
the invention are possible in view of the teachings herein without 
departing from the scope of the invention as defined in the appended 
claims.