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8/18/2019 Bilotti 1966
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1966 PROCEEDIKGSETTERS 1093
b) nonzero output conductance of the equivalent generator for
th e local oscillator circuit, which occasions small changes in
the effective values of the crysta l mount.
CONCLUSIOK
Our work shows that classical calculations
of a
microwave mixer
diode performances are still valid with an X band intermediate fre-
quency, and that theygive a good value for th e conversion
loss.
Another interest of microwave intermediate requency n re-
ceivers is the drastic decrease of local oscillator noise, and the large
pass band (absolute value) which may be used. This is specially use-
ful in radar systems.3
Smaller conversion loss may be obtainable with junction diodes.4
We think that we can improve these results
by
trying varactors
MME.
LIGEON
E.
PIC
Ecole Nationale Superieure d'Electronique
University of Grenoble
Grenoble, France
and tunnel diodes as microwave mixers.
PhiliDS. vol. 25. no. 8 D D . 209-222. 1963-1964.
8 H. ALlaries. Une installation de radar pour ondes de 4 mm. Rro. Technique
type Ga s Schottky barrier epitaxial diodes with a novel contacting technique,
Proc.
I EEE
Conespondcncc). voL 53, pp. 2130-2131. December 1965
4
D..T. Y ok g and-J. C. I ,' 'Millimeter frequency conversion using Au-8;
Operation of a MOS Transistor
as
a
Variable Resistor
An FET
transistor, operating below saturation, can perform the
function of a variable resistor within a limited voltage range. This
restriction is due to the asymmetry and nonlinearity of its charac-
teristics, especially for reverse drainpolarity. It has been shown
elsewhere tha t
i n
the case of the junction
FET
a perfect symmetry
and
a
remarkable improvement in linear ity is achieved if half of the
drain voltage is fed back to he gate [ l ] , [2]. The following work
shows tha t the same situation holds f o r a
MOS
transistor
if
the sub-
str ate is kept floating.
arrangement where half of the drain-voltage is fed back~to-the -gat;.Foi-G%I
parative purposes, the dc gate-voltage i s
always
adjusted to th e Same value as
Fig.
l a l .
c) Theoretical drain characteristics of an MOS transistor for both
cases
of
Fig. l(a)and (b).
8/18/2019 Bilotti 1966
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PROCEEDISGSFHEEEE AUGUST
200
m v l s q u a r e
(a)Drain-current vs. drain-voltagecharact eristic s of
a
p-channelenhancement
MOS transistor (Vr= -3 V) for VG
=
-3.1 V.. -3.5 V, and
5 V.
2 V l s q u a r e
(c) Drain characteristics of the sam e tran sistor as n Fig. 2(a).
Fig. 2.
200 m v l s q u a r e
(b) The Same as Fig. 2(a) but with
50
percent feedback from drain to gate
as shown in Fig.1 b)
2
V s q u a r e
(d) The Same as Fig. P(c) with the feedback arrangement
of Fig.
1
b).
8/18/2019 Bilotti 1966
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