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Publication numberUS2663754 A
Publication typeGrant
Publication dateDec 22, 1953
Filing dateJul 18, 1950
Priority dateJul 18, 1950
Publication numberUS 2663754 A, US 2663754A, US-A-2663754, US2663754 A, US2663754A
InventorsBianco Joseph F
Original AssigneeBianco Joseph F
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Slotted dielectric coaxial line and process for making same
US 2663754 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Dec. 22, 1953 .nici


Application July 18, 1950, Serial N o. 174,542


(Granted under Title 35, U. S. Code (1952),

sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to a slotted dielectric coaxial line of the kind used in radio, radar and television laboratories to measure the wave lengths of high frequency currents passing through it or along it.

A novel, expeditious and precise method for making the line forms a part of the invention.

Briefly stated, the line comprises a centerlessground and electroplated central conductor, which may be of steel and which has reverse tapered ends; a cast or injection-molded dielectric about the central conductor, which dielectric is machined to size, including tapers, and then electroplated; force fit tubing on the ends of the dielectric; an electrically conductive surface plated on the dielectric and a narrow longitudinal machined or molded slot for the accommodation of a probe.

One object of the invention is the provision of a precision coaxial line for close measurement of wave lengths.

Another object is the reduction of machining time, the elimination of joints, the establishment of a close, airfree junction of the conductor and the dielectric and the elimination of inside machined taper with consequent increase in the precision of the machining Operations.

Another object is the provision of a particularly eicient manufacturing method for making the line.

Referring now to the drawings, Fig. 1 is a longitudinal section taken through the slot and the solid parts of the line.

Fig. 2 is a cross section of the line taken on the line 2 2 of Fig. l.

ll'l is a central conductor which may be of copper, brass, steel or equivalent metal. If of steel, it is copper or brass-plated as indicated by the heavy line IO'. At its ends ll the diameters are reverse-tapered at an angle of about giving sufiicient enlargement to hold a dielectric I 2 tightly on the conductor ID without the possibility of removal over the ends.

The dielectric is electroplated after molding or casting by coating its exterior with a highly conductive material, for example a paste or liquid made of finely divided graphite or copper powder plus a vehicle. Such compositions are well known. The coatng may be accomplished by spraying, brushing or dipping. The electroplating is accomplished in the conventional manner,

2 using available techniques to insure that the deposited material is not stressed.

The dielectric is a low-loss mechanically stable Synthetic resin which may be of either the kind which must be cast or the kind which may be injection molded and plated with copper or brass, preferably, as indicated by the heavy line |2'. General Electric phenolic resin Textolite is an example of the first, while polystyrene (the preferred material) is an example of the second. The depth of dielectric may be widely varied as long as it is suicient to prevent puncture by sparks or arcs resulting from high voltages.

As shown by the drawings, the cable has a long slot 13 intermediate the ends thereof for the reception of a probe, In practice, the slot |3 is about 1% wide and extends to the bare conductor. It may be produced by milling or molding. Other widths may be used. It is as long as the frequency range to be covered requires without interfering with the dielectric ends M. These are tapered outwardly at an angle approximating 45 which however, is not critical. An air termination, which is desirable, is thereby produced. Thin metal ends 15 made of tubing and attached with a press fit are used to complete the cable, these being preferably brass, which may be nickel or chrome plated. Standard coaxial cable fittings may be used to join pieces of cable of the above description. The dielectric of different pieces may be cemented together and electrical connections may be aided by applying conductive pastes (which are known) to the junctions to make the connections electrically good. Irregular bends may be molded into the cable if required. Special tapers may also be employed.

The method of using the cable and probe to measure wave lengths is conventional, so will not be described.

What I claim is:

1. A coaxial cable comprising a central conductor, reverse tapered ends on said ccnductor, a plating of a highly conductive metal on said conductor and ends and a dielectric tightly molded about said conductor and ends to the furthest extremities thereof, said dielectric being electroplated on its outer surface and having a narrow longitudinal slot substantially deep enough to reach the conductor.

2. A coaxial cable according to claim 1 having in addition tapered ends on said dielectric and cylindrical tubing surrounding the tapered portion thereof, said tubing being attached to the outer surface of said dielectric with a press fit.

3. A coaxia cable having a central conductor of exact predetermined diameter, reversely tapered ends on said conductor, an envelope of dielectric over said conductor and ends, a thin coat of highly conductive metal over said dielectric, tapered ends on said dielectric, and metallic tubng ends over said tapered ends, said tubing ends being in good electrical contact With said metal coat.

4. The process of making a coaxial Cable which comprises centerless grinding'a steel condutr with reverse tapered ends, electroplati'ng the' tire conductor with a highly conduetive metal,V

molding a covering of dielectric about the conductor, said covering consisting of 'a mechanical;

then electroplatng the outer surface VVof said covering with a highly conduct'ive metal.

5. The process set forth in claim 4 and in addition the steps of molding tapered ends and a longitudinal slot in the cable and attaching highly conductve tubing ends to the cable over the tapered ends with a tight fit over the plated dielectric. w l


References Cited in the file of this patent UNITEDv STATES PATENTS Numbe Name Date 2,Q61,3 E9Q Coupier Nov. 17, 1936 2 ,129,712` Southworth Sept. 13, 1938 23864119' vJacil Oct. 2, 1945 2,4 1Q,59'7V Peterson May 21, 1946 2",4'06,945 Fell Sept. 3, 1946 21,454,`30` Tille Nov. 23, 1948

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2061350 *May 22, 1935Nov 17, 1936Emmanuel Milde CharlesMethod of covering wires
US2129712 *Dec 9, 1933Sep 13, 1938American Telephone & TelegraphTransmission of energy effects by guided electric waves in a dielectric medium
US2386119 *Dec 30, 1942Oct 2, 1945Jack Norman HMethod of continuously shielding wire in unlimited lengths
US2400597 *Oct 6, 1943May 21, 1946Rca CorpStanding wave indicator for radiofrequency transmission lines
US2406945 *Feb 16, 1943Sep 3, 1946Rca CorpInsulator for concentric transmission lines
US2454530 *Oct 13, 1944Nov 23, 1948Philco CorpPhase adjuster for fixed-branch wave guide
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3287490 *May 21, 1964Nov 22, 1966United Carr IncGrooved coaxial cable
US3639674 *Jun 25, 1970Feb 1, 1972Belden CorpShielded cable
US6825418May 16, 2000Nov 30, 2004Wpfy, Inc.Indicia-coded electrical cable
US7465878Aug 18, 2004Dec 16, 2008Wpfy, Inc.Indicia-marked electrical cable
US7954530Jun 15, 2009Jun 7, 2011Encore Wire CorporationMethod and apparatus for applying labels to cable or conduit
US8278554Dec 10, 2008Oct 2, 2012Wpfy, Inc.Indicia-coded electrical cable
US8454785Apr 22, 2011Jun 4, 2013Encore Wire CorporationMethod for applying labels to cable or conduit
US8826960Apr 21, 2011Sep 9, 2014Encore Wire CorporationSystem and apparatus for applying labels to cable or conduit
US9321548Apr 30, 2013Apr 26, 2016Encore Wire CorporationMethod for applying labels to cable or conduit
US9409668Nov 10, 2014Aug 9, 2016Encore Wire CorporationMethod and apparatus for applying labels to cable
US9446877Aug 6, 2014Sep 20, 2016Encore Wire CorporationSystem and apparatus for applying labels to cable or conduit
US9452856Nov 10, 2014Sep 27, 2016Encore Wire CorporationMethod and apparatus for applying labels to cable
U.S. Classification174/102.00C, 29/600, 29/458, 29/828, 333/27
International ClassificationG01R1/26, G01R1/00
Cooperative ClassificationG01R1/26
European ClassificationG01R1/26