Ex parte Weitzel et al

Board of Patent Appeals and Interferences

Sep 23, 1998

08298721 (B.P.A.I. Sep. 23, 1998)

Application for patent filed August 31, 1994.1
1
Paper No. 18
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today
(1) was not written for publication in a law journal and
(2) is not binding precedent of the Board.
UNITED STATES PATENT AND TRADEMARK OFFICE
_______________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________
Ex parte CHARLES E. WEITZEL
and
CARL SHURBOFF
______________
Appeal No. 96-1203
Application 08/298,721 1
_______________
ON BRIEF
_______________
Before THOMAS, JERRY SMITH and LEE, Administrative Patent Judges.
JERRY SMITH, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on the appeal under 35 U.S.C. § 134
from the examiner’s rejection of claims 1-12, which constitute
all the claims remaining in the application. An amendment after
Appeal No. 96-1203
Application 08/298,721
2
final rejection was filed on September 5, 1995 and was entered
by the examiner. This amendment cancelled claims 13-16.
The disclosed invention pertains to a complementary
heterojunction amplifier particularly designed for use as a
radio frequency amplifier. The amplifier of the invention has
a P-channel heterojunction transistor and an N-channel
heterojunction transistor connected together. The gate width
of the P-channel transistor is selected so that the P-channel
transistor has the same transconductance as the N-channel
transistor. The gate length of the N-channel transistor has a
value so that the input impedance to the P-channel transistor is
approximately equal to the input impedance of the N-channel
transistor.
Representative claim 1 is reproduced as follows:
1. A complementary heterojunction amplifier comprising:
a P-channel heterojunction transistor having a first gate
width, a first transconductance, and a first input impedance; and
an N-channel heterojunction transistor having a first gate
length, a second transconductance, and a second input impedance
wherein the first gate width has a value so that the first
transconductance and the second transconductance are
approximately equal and wherein the first gate length has a value
so that the first input impedance is approximately equal to the
second input impedance.
The examiner relies on the following reference:
Redfern 5,329,184 July 12, 1994
Appeal No. 96-1203
Application 08/298,721
3
Claims 1-12 stand rejected under 35 U.S.C. § 103. As
evidence of obviousness the examiner offers Redfern taken alone.
Rather than repeat the arguments of appellants or the
examiner, we make reference to the briefs and the answer for the
respective details thereof.
OPINION
We have carefully considered the subject matter on
appeal, the rejection advanced by the examiner and the evidence
of obviousness relied upon by the examiner as support for the
rejection. We have, likewise, reviewed and taken into
consideration, in reaching our decision, the appellants’
arguments set forth in the briefs along with the examiner’s
rationale in support of the rejection and arguments in rebuttal
set forth in the examiner’s answer.
It is our view, after consideration of the record before
us, that the evidence relied upon and the level of skill in the
particular art would not have suggested to one of ordinary skill
in the art the obviousness of the invention as set forth in
claims 1-12. Accordingly, we reverse.
Appellants have indicated that for purposes of this
appeal the claims will all stand or fall together as a single
group [brief, page 3]. Consistent with this indication
Appeal No. 96-1203
Application 08/298,721
4
appellants have made no separate arguments with respect to any of
the claims on appeal. Accordingly, all the claims before us will
stand or fall together. Note In re King, 801 F.2d 1324, 1325,
231 USPQ 136, 137 (Fed. Cir. 1986); In re Sernaker, 702 F.2d 989,
991, 217 USPQ 1, 3 (Fed. Cir. 1983). Therefore, we will only
consider the rejection against independent claim 1 as
representative of all the claims on appeal.
In rejecting claims under 35 U.S.C. § 103, it is
incumbent upon the examiner to establish a factual basis to
support the legal conclusion of obviousness. See In re Fine,
837 F.2d 1071, 1073, 5 USPQ2d 1596, 1598 (Fed. Cir. 1988).
In so doing, the examiner is expected to make the factual
determinations set forth in Graham v. John Deere Co., 383 U.S. 1,
17, 148 USPQ 459, 467 (CCPA 1966), and to provide a reason why
one having ordinary skill in the pertinent art would have been
led to modify the prior art or to combine prior art references to
arrive at the claimed invention. Such reason must stem from some
teaching, suggestion or implication in the prior art as a whole
or knowledge generally available to one having ordinary skill in
the art. Uniroyal, Inc. v. Rudkin-Wiley Corp. , 837 F.2d 1044,
1051, 5 USPQ2d 1434, 1438 (Fed. Cir.), cert. denied, 488 U.S. 825
(1988); Ashland Oil, Inc. v. Delta Resins & Refractories, Inc. ,
Appeal No. 96-1203
Application 08/298,721
5
776 F.2d 281, 293, 227 USPQ 657, 664 (Fed. Cir. 1985), cert.
denied, 475 U.S. 1017 (1986); ACS Hosp. Sys., Inc. v. Montefiore
Hosp., 732 F.2d 1572, 1577, 221 USPQ 929, 933 (Fed. Cir. 1984).
These showings by the examiner are an essential part of complying
with the burden of presenting a prima facie case of obviousness.
Note In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444
(Fed. Cir. 1992).
With respect to representative, independent claim 1, the
examiner cites Redfern as suggesting the use of CMOS circuitry
for amplifiers and providing a motivation for equalizing the
transconductance of the transistors [answer, page 3]. The
examiner continues that the equalization of operating parameters
in Redfern would inherently affect the gate widths and lengths of
the transistors [Id.]. Finally, the examiner asserts that any
engineer would have found it obvious to equalize other operating
parameters such as input impedance [ Id.].
Appellants argue that Redfern’s equalization of
transconductance in the P-channel and N-channel transistors of an
inverter does not suggest the equalization of input impedances
for such channel transistors of a heterojunction amplifier
[brief, page 4]. Appellants also argue that the discovery that
“increasing the gate length of transistor 11 [the N-channel
Appeal No. 96-1203
Application 08/298,721
6
transistor] reduces the input impedance of transistor 11 with
only a minor affect on the transconductance of transistor 11" was
a discovery which would have been unexpected to the person of
ordinary skill in the art [brief, page 6]. Finally, appellants
argue that Redfern has no recognition of the problem of quiescent
power dissipation so that Redfern provides no motivation to
equate input impedances, especially by modifying the N-channel
gate length as recited in the independent claims [brief, page 7].
Since the obviousness issue must be decided on the record
before us, we are constrained to reverse the rejection as set
forth by the examiner. We basically agree with all of
appellants’ arguments as set forth in the briefs. Redfern’s
suggestion to equate transconductance of the N-channel and
P-channel transistors in an inverter cannot be said to suggest
equating the input impedances of the N-channel and P-channel
transistors of an amplifier. Although the examiner is correct in
his assertion that any change in the dimensions of the transistor
gates will have an effect on the transconductance and the
impedance of a transistor, this general assertion does not
suggest that input impedances of the N-channel and P-channel
transistors should be made equal.
Appeal No. 96-1203
Application 08/298,721
7
The form of claim 1 recites a complementary hetero-
junction amplifier in which the P-channel transistor and the
N-channel transistor have approximately equal transconductances
and approximately equal input impedances. It would seem that any
such amplifier having these equal transconductances and equal
input impedances would necessarily have gate widths and lengths
that satisfy the language of claim 1. A key feature, however, is
that the input impedances of the N-channel and the P-channel
transistors are approximately equal. As noted above, Redfern
only teaches equating transconductances in the P-channel and N-
channel transistors of an inverter.
The examiner’s assertion that the invention of claim 1
would have resulted from an obvious design choice of parameters
as suggested by Redfern simply is not supported by the evidence
on this record. We are not inclined to dispense with the
requirement that the examiner present factual support for
contested positions on inherency or design choice. Since there
is no suggestion that the input impedance between the N-channel
and P-channel transistors should be made approximately equal, we
do not sustain the rejection of representative claim 1. Since
all the claims stand or fall together, we do not sustain the
rejection of any of claims 1-12.
Appeal No. 96-1203
Application 08/298,721
8
The decision of the examiner rejecting claims 1-12 is
reversed.
REVERSED
JAMES D. THOMAS )
Administrative Patent Judge )
)
)
)
JERRY SMITH ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
JAMESON LEE )
Administrative Patent Judge )
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