Патент USA US2104915код для вставки
Jan. 11, 1938. B_ _1_ THOMPSON 2,104,915 TUNED OSC ILLATOR C IRCUIT Filed Sept. 29, 1954 (434,677)’ /3 / INVENTOR dJ. 7/1’0 P 0N > BY W | ma, ATTORNEY Patented Jan. 11, 1938 2,104,915 TUNED OSCÍLLATOR UIRCUET `Browder J. Thompson, Summit, N. J., assigner to Radio Corporation of America, a corpora tion of Delaware Application September 29, 1934, Serial No. 746,124 12 Claims. This invention relates uo a new form of short wave tuned oscillatory circuit which is character ized by extremely low loss. The customary tuned circuits used on wave 5 lengths of several meters and less comprise par allel or concentric lines having distributed con stants, and small circuits having lumped induct ance and capacitance. Of these, only the concen Y tric lines give high impedance, since the radiation, lll eddy current, and stray dielectric losses of the other circuits are usually high. Concentric. lines have the disadvantage of requiring a conductor at least one-quarter o1" a wave length long. Ú It has been proposed to provide a tuned circuit 1*" consisting oi two copper hemispheres supported on a copper rod with flanges on the hemispheres forming a timing capacity, while the supporting rod forms the inductance. Such an arrangement, however, introduces considerable loss in the cir co cuit, because of the high external electrostatic ñeld set up. For the same reason, the tuning is affected by stray capacitances. The present invention provides a highly eñîl cient tuned oscillatory circuit having lsubstantially no external magnetic or electric iielcl, and this is achieved by the use of inner and outer conductors, the surface ci the outer conductor being substan tially continuous electrically so that there is no external magnetic or electric ?eld, and the inner :A C) conductor being connected to the external ele ments ci the circuit by means of one or more leads l extending through the outer conductor. Al though it is appreciated that there are some losses produced by the connecting leads, the losses con sist principally of resistance losses of the inner conductors and can be made to be very low. One advantage of the present invention lies in the sub stantial freedom of the circuit from the effects oi stray tuning due to movements of dielectrics and 40 conductors near the surface. The invention is described in more detail in connection with the accompanying drawing, wherein Figs. 1-3 illustrate different preferred embodiments of the invention. Fig. l shows a cross section of a tuning circuit comprising a continuous hollow sphere I, prefer ably copper, enclosing two- rods 2, 3 with the in ner ends terminating in discs ll, 5 in the center to form a tuning capacity, the length of rod between 50 discs 4, 5 and the surface of sphere l serving as the tuning inductance. Leads 6 are brought out of the tuning circuit through holes in the sphere. These leads can be tapped oil anywhere along the rods to match any external impedance. Fig. 2 shows another embodiment which com prises a metallic cylinder l, preferably copper or brass, enclosing copper rods 8, 9 terminating in discs ll, 5 to form the inductance and capacitance respectively, as in Fig. l. Rod 8 is herein shown threaded at the end to permit variation in the Ul capacity between the discs d, 5, merely by a turn of the tuning knob Iß. This arrangement is simpler to construct than the spherical arrange ment of Fig. l, and possesses all of the advantages oi the latter. in Fig. 3 is shown an arrangement which, in effect, is one-half oi that of Fig. 2, with the lead lí brought out from the end of the support rod E2. The plate i3 at the free end of the rod l2 provides one terminal oi a capacitance whose 15 other terminal is the outer surface oi the cylinder. The value of this capacitance may be adjusted by varying the length of rod l2. This embodiment has a considerable advantage in mounting, as the circuit can be placed directly on the ground plate of the apparatus. Water cooling of the inner conductor l2 may be provided, if desired, by making the conductor hol low and causing a iiow of cooling iiuid through it by means oi an internal tube. Since, at high fre quencies, the skin effect causes practically all the current to flow near the surface of the conductor, it will be readily understood that the resistance would not be appreciably increased by removing material from the interior of the conductor. For ‘ the same reason, very little loss is introduced by the cooling fluid. If mercury is employed for the cooling, little or no loss will be introduced due to it comparatively low resistance. Another advantage of the present invention, besides that or“ very low loss, is that the improved oscillatory circuits enable tuned circuits to be constructed for very short wave lengths of the order of one meter and less, while still providing appreciable lumped capacity, since the induct ance can be made very low. Although the arrangements illustrated in the drawing are preferred and have been shown to be symmetrical, it should be understood that the enclosing surface need not have any symmetrical shape or be a surface of revolution in order to practice the invention; nor is it necessary that the inner conductors be axially located or the condenser be substantially in the center. Lack ï of symmetry o1", or small openings in, the outer surface have no serious adverse eiîect, and, elec trically, are not greatly inferior to any ci the idealized structures illustrated. The essential thing is that the outer surface be substantially 2. 2,104,915 continuous electrically, so that there is no ex 7. A high frequency tuned oscillatory circuit ternalrmagnetic or electric field. comprising a substantially continuous metallic What is claimed is: surface enclosing an inductance in the form of two metallic rods and a capacitor in the form of a pair of separated metallic plates, one end of each rod electrically terminating at one of the plates and the other end at the enclosing surface, and means for adjusting the length of one of the rods n l. An ultra high frequency tuned Voscillatory circuit comprising a container in the form of a metallic surface of revolution, a lumped capaci tor substantially in the center of said surface of revolution, and connected to said surface by in ductance in the form'of support rods, and a lead within said'surface of revolution connected to the outer'surface of each of said support rods between the> ends thereof and extending there from externally of and through said surface of within saidv surface for varying the distance be~ tween said plates, and a'lead connected to the 10 outer surface of each of said support rods and extending externally of and through said sur face: revolution, said leads being physically separated 15 from each other. . 8. An ultra-high frequency tuned oscillatory ~ 2. An 'ultra high frequency oscillatory circuit » i comprising a substantiallyrenclosed metallic sur substantially continuous metallic surface, a lumped' capacitor substantially inthe center of said surface and connected to said'surface by faceV of revolution, a capacitor comprising two separated plates substantially in the center of. 20 said enclosed surface of revolution, a metallic'` supporting rod devoid of concentrated reactance directly connecting each of said plates to said circuit comprising a container in the form of a 15 inductances in the form of Vsupport rods, and a lead' within said container connected to the outer surface of each of said support rods between the ends thereof and extending therefrom externally surface, said rods forming an inductance which, of and through said container, said leads being taken together with the plates of said capacitor, physically Vseparated from each other. 25 comprise the oscillator circuit, the adjacent ends 9. A high frequency tuned oscillatory circuit 25 of said rods being separated substantially by the distance between said plates, and leads coupled ' comprising a container in the form of a substan tially continuous metallic surface, a lumped ca to the outer surface of said rods and extending pacitor within said surface, and a pair o-f in substantially perpendicular thereto and through ductance elements in the form of linear conduc 30. said surface of revolution. tors devoid of concentrated reactance directly 30 3. A high frequency tuned oscillatory circuit in connecting saidr capacitor to said surface, and a accordance with claim 2, characterized in this lead within said container connected to the outer that said enclosed surface of revolution is'V a sphere. 4. An ultra high frequency oscillatory circuit comprising a substantially enclosed cylinder, a capacitor comprising two separated plates» sub stantially in the center of said enclosed cylinder, a metallic supporting rod devoid of concentrated reactance directly connecting each of said plates to a wall of said enclosure, said rods forming an ductance which, taken together with the plates of said capa itor, comprise the oscillatory circuit, the adjacenî ends of said rods being separated V45 substantially by the distance between said plates, surface of each of said support rods between the ends thereof and extending externally of and through said container. l0. A highV frequency tuned oscillatory circuit comprising a container in the form of a sub stantially continuous metallic surface, a lumped capacitor within said surface, a pair of induc tance elements in the form of linear conduc 40 tors devoid of concentrated reactance directly connecting said capacitor- to said surface, and a lead conductively coupled to the outer surface of each of said inductance elements extending and leads coupled to said rods and extending ~ from within said container externally of said os substantially perpendicular thereto and through said cylinder. 5. An ultra high frequency oscillatory circuit 50 comprising a substantially enclosed metallic sur face of revolution, a capacitor comprisingrtwo plates substantially in the center of said enclosed surface of revolution, a metallic supportingV rod for each plate of said capacitor connecting the 55 plate to the surface, said rods forming an in ductance which, taken togetl'ier‘with the plates of said capacitor comprise the oscillatory circuit, means located externally of said surface for ad justing one of said support rods with respect to 60 the other, for Varying the capacity betweenr said plates, and leads coupled to said rods and ex tending substantially perpendicular thereto and through said surface of revolution. 6. An ultra high frequency tuned'oscillatory 65 circuit comprising a container in the form of a metallic surface of revolution, a lumped capacitor substantially in the center of said surface of revolution and connected to said surface by'in ductance'in the form of sup-port rods, and leads 70 extending from said support rods externally1 of said surface of revolution, said leads being ad justable over the lengths of said rods. cillatoryV circuit, and substantially >at a right >angle to its associated inductance elements.Y 11. A high frequency tuned oscillatory circuit comprising a container in the form of a substan- tially continuous metallic surface, a lumped ‘ca pacitor within said surface and connected to said surface by inductance in the form of two sup port rods arranged substantially inthe same straight line, and leads conductively coupled toV the outer'surface of said support rods‘and extend ing externally of said surface Yat substantially a right angle to said support rods. 12. A. high frequency tuned oscillatory circuit comprising a substantially continuous metallic surface enclosing an inductance in the form of 60 two metallic rods, and a capacitor in the form of a¿ pair of separated metallic plates, one end of each rod electrically terminating at one of the ` plates and the other end at the enclosing sur face, means for adjustingthe length of Vone of 65 said rods within said surface for varying the dis tance between said plates, and leads adjustable over the lengths of said rods and extending'there from externally of said metallicsurface. BRQWDER J. THOMPSON.