Andrew Corp. v. Gabriel Electronics, Inc.

Citation6 USPQ2d 2010,847 F.2d 819
Decision Date25 May 1988
Docket Number86-1690 and 87-1193,Nos. 86-1689,s. 86-1689
Parties, 6 U.S.P.Q.2d 2010 ANDREW CORPORATION, Plaintiff-Appellant, v. GABRIEL ELECTRONICS, INC., Defendant/Cross-Appellant. Appeal
CourtUnited States Courts of Appeals. United States Court of Appeals for the Federal Circuit

Stephen G. Rudisill, Arnold, White & Durkee, Chicago, Ill., argued for plaintiff-appellant.

Charles Pfund, Dike, Bronstein, Roberts, Cushman & Pfund, Boston, Mass., argued for defendant/cross-appellant. With him on the brief was Robert M. Asher.

Before FRIEDMAN, NEWMAN, and ARCHER, Circuit Judges.

PAULINE NEWMAN, Circuit Judge.

Andrew Corporation (Andrew) and Gabriel Electronics, Inc. (Gabriel) appeal and cross-appeal two final judgments of the United States District Court for the District of Maine. The court held 1 Andrew's U.S. Patent No. 4,410,892 (the Knop patent) invalid for indefiniteness, but if valid infringed by Gabriel. The court's second judgment 2 held Gabriel's U.S. Patent No. 3,550,142 (the Dawson patent) not infringed by Andrew. We reverse the judgment of invalidity of the Knop patent and affirm the other aspects of both judgments.


Both the Knop and the Dawson patents relate to improvements in horn reflector microwave antennas used in long distance telephone and data communication networks. As described by the district court, a horn reflector antenna generally is constructed of an inverted vertical "feed" cone and a horizontal cylinder, which intersect at right angles. The microwave beam enters the feed cone vertically from the apex of the cone; an angled paraboloidal reflector catches the unfocused beam as it rises, focuses it into a coherent beam, and reflects it out the horizontal cylinder and on to the next antenna in the network.

The performance of such antennas is evaluated using the standard criteria of "gain" and "pattern". "Gain" refers to the strength of the focused beam relative to the original unfocused beam; higher gain allows transmission over longer distances. "Pattern", or "Radiation Pattern Envelope" ("RPE"), refers to the distribution of microwave energy outside the main beam in what are referred to as "sidelobes".

These patterns are measured in both the horizontal ("E-plane") and the vertical ("H-plane") directions. Normally, the E-plane has more energy distributed outside the main beam. This is referred to as having "higher sidelobes" or "a wider pattern", and results in unwanted interference with nearby antennas. The overall performance of an antenna is measurable by the E-plane and H-plane patterns.


The Knop patent specification describes a horn reflector antenna that reduces interference Indefiniteness--35 U.S.C. Sec. 112

with other antennas without significant loss of gain. This improved result is obtained by placing absorber material deep inside the conical feed horn. The use of absorber material had been shown in the prior art, placed in the first few inches of the conical feed horn to dampen stray radiation. According to the prior art, placing absorber material deeper into the cone causes unsatisfactory loss of gain. Knop teaches that this deep absorber acts by reducing the width of the E-plane RPE without significantly affecting the quality of the H-plane RPE, thereby improving overall performance of the antenna.


The district court held the Knop patent claims invalid, stating that terms in the claims such as "approach each other", "close to", "substantially equal", and "closely approximate", with reference to the E-plane and H-plane RPEs, were too vague to satisfy the requirement of definiteness stated in 35 U.S.C. Sec. 112. 3 One or more of these terms appears in each of the claims, as illustrated in the following independent and dependent claims:

1. A conical horn-reflector antenna comprising the combination of:

a paraboloidal reflector forming a paraboloidal reflecting surface for transmitting and receiving microwave energy,

a smooth-walled conical feed horn for guiding microwave energy from the focus of said paraboloidal reflecting surface to said reflector, and

a lining of absorber material on the inside wall of the horn for reducing the width of the RPE in the E plane of the antenna without significantly increasing the width of the RPE in the H plane, said absorber increasing the Eigen value E and the spherical hybridicity factor Rs sufficiently to cause the E plane and H plane RPEs to approach each other.

3. A conical horn-reflector antenna as set forth in claim 2 which produces substantially equal E and H plane illumination patterns.

6. A method as set forth in claim 5 wherein said lining of absorber material increases the taper of the field distribution along the radii of said horn in the E plane to closely approximate the taper of the field distribution along the radii of said horn in the H plane. [emphases added]

The criticized words are ubiquitous in patent claims. Such usages, when serving reasonably to describe the claimed subject matter to those of skill in the field of the invention, and to distinguish the claimed subject matter from the prior art, have been accepted in patent examination and upheld by the courts. As this court put it in Rosemount, Inc. v. Beckman Instruments, Inc., 727 F.2d 1540, 1546-47, 221 USPQ 1, 7 (Fed.Cir.1984):

Beckman attacks the claims as indefinite, primarily because "close proximity" is not specifically or precisely defined. As stated in the district court's Memorandum Decision, "to accept Beckman's contention would turn the construction of a patent into a mere semantic quibble that serves no useful purpose."

In Rosemount the district court found that " 'close proximity' is as precise as the subject matter permits". Id. In Seattle Box Co. v. Industrial Crating & Packing, 731 F.2d 818, 826, 221 USPQ 568, 573-74 (Fed.Cir.1984) (citing W.L. Gore & Associates, Inc. v. Garlock, Inc., 721 F.2d 1540, 1557, 220 USPQ 303, 316 (Fed.Cir.1983), cert. denied, 469 U.S. 851, 105 S.Ct. 172, 83 L.Ed.2d 107 (1984)), the court remarked that "substantially equal" is a term of degree, and that its acceptability depends on "whether one of ordinary skill in the art would understand what is claimed ... in light of the specification", even if experimentation may be needed.

In W.L. Gore & Associates, Inc. v. Garlock, Inc., No. 87-1296, 842 F.2d 1275, 1280, 6 USPQ2d 1277, 1282 (Fed.Cir.1988), this court stated that an "imprecise claim "If the claims, read in the light of the specification, reasonably apprise those skilled in the art both of the utilization and scope of the invention, and if the language is as precise as the subject matter permits, the courts can demand no more."

                limitation, such as the phrase 'about 100% per second' " does not impart invalidity to the claims, but is to be considered in determination of infringement.   See also Hybritech Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1385, 231 USPQ 81, 95 (Fed.Cir.1986) ("the claims, read in light of the specification, reasonably apprise those skilled in the art and are as precise as the subject matter permits.  As a matter of law, no court can demand more"), cert. denied, --- U.S. ----, 107 S.Ct. 1606, 94 L.Ed.2d 792 (1987);  Shatterproof Glass Corp. v. Libbey-Owens Ford Co., 758 F.2d 613, 624, 225 USPQ 634, 641 (Fed.Cir.), cert. dismissed, 474 U.S. 976, 106 S.Ct. 340, 88 L.Ed.2d 326 (1985)

(quoting Georgia-Pacific Corp. v. United States Plywood Corp., 258 F.2d 124, 136, 118 USPQ 122, 132 (2d Cir.), cert. denied, 358 U.S. 884, 79 S.Ct. 124, 3 L.Ed.2d 112 (1958)).

The Manual of Patent Examining Procedure instructs examiners in a similar vein. See MPEP Sec. 706.03(d):

[An examiner] should allow claims which define the patentable novelty with a reasonable degree of particularity and distinctness. Some latitude in the manner of expression and the aptness of terms should be permitted even though the claim language is not as precise as the examiner might desire. [emphasis in original]

Andrew asserted that the Knop claims could not reasonably be expressed more precisely; and indeed the court found that it "became very clear during trial ... that curves showing RPEs for horn antennas will never be identical". Words similar to those used in the Knop claims appear in prior art patents that were of record in the district court, dealing with similar technology. For example, claim 1 of U.S. Patent No. 3,305,870 to Webb describes a "radiation pattern whose magnitudes in both the E and H planes are substantially equal".

Neither the record nor the law supports Gabriel's position that one of ordinary skill in the art would not know when the RPEs were "substantially equal" or "closely approximate". The district court's ruling is contrary to authority, and the holding of invalidity on this ground is reversed.


The district court observed that the RPEs change gradually with increased depth of absorber in the cone. The court held that the claims must specifically delineate the point at which infringement starts, and that if such point does not correspond to an unexpected change in properties, the claims are fatally flawed under 35 U.S.C. Sec. 112. The court said:

There is no unexpected change in the E-plane at any of the levels of absorber which gives a clue to what is intended by the patent claims. The choice of a point beyond which there is infringement, therefore, is arbitrary and the point unforeseeable. [footnote omitted]

The district court held that the outer limit of the claim scope must coincide precisely with the point at which the claimed invention comes into scientific being. The court referred to Brown-Bridge Mills, Inc. v. Eastern Fine Paper, Inc., 700 F.2d 759, 763, 217 USPQ 651, 655 (1st Cir.1983), which quoted with approval the holding originating in Kwik-Set, Inc. v. Welch Grape Juice Co., 86 F.2d 945, 947, 32 USPQ 104, 106 (2d Cir.1936) that "It is only where the selected [i.e., claimed] point corresponds with the physical phenomenon and the patentee has discovered...

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