COAXIAL CAVITY NEGATIVE RESISTANCE AMPLIFIERS AND OSCILLATORS
First Claim
1. In a high-frequency energy device, semiconductor means, resonant circuit means coupled to said semiconductor means, said resonant circuit means including biasing means connected across said semiconductor means for biasing said latter means to its negative resistance state, said biasing means including first and second quarter-wave line portions of different characteristic impedances, high-frequency coupling means adjacent the junction of said first and second quarter-wave line portions adapted for interchange of high-frequency energy with at least one utilization device.
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Abstract
A semiconductor diode interiorly coupled to fields within a coaxial line cavity resonator serves as a negative resistance device, amplifying the high frequency fields present within the cavity. The combination forms a single port microwave amplifier or oscillator. A simple resistor, placed in the diode bias circuit in series with the diode, eliminates spurious modes of high frequency oscillation within the cavity.
8 Citations
21 Claims
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1. In a high-frequency energy device, semiconductor means, resonant circuit means coupled to said semiconductor means, said resonant circuit means including biasing means connected across said semiconductor means for biasing said latter means to its negative resistance state, said biasing means including first and second quarter-wave line portions of different characteristic impedances, high-frequency coupling means adjacent the junction of said first and second quarter-wave line portions adapted for interchange of high-frequency energy with at least one utilization device.
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2. A high-frequency energy device according to claim 1 wherein said resonant circuit means is a coaxial line cavity resonator.
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3. A high-frequency energy device according to claim 1, wherein capacitive tuning means is disposed adjacent the junction of said first and second quarter-wave line portions opposite said high-frequency coupling means.
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4. A microwave signal amplifying device comprising semiconductor means, resonant circuit means connected across said semiconductor means, said resonant circuit means including means across said semiconductor means for biasing said latter means to its negative resistance state, said biasing means including a first quarter-wave transmission line portion joined to a resistive means, said resistive means being surrounded in part by a second quarter-wave transmission line portion, said resistive means being connected to said second quarter-wave transmission line element adjacent said semiconductor element, means for abstracting energy from said signal amplifying device.
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5. In a high-frequency energy device, a hollow body defining a cavity with interior walls of high electrical conductivity, said cavity having a first end wall integrally formed in said body, said cavity having a second end wall insulated from said body by a dielectric member for forming a bypass condenser for high frequency energy within said cavity, a series circuit conductively coupling said first wall to said second wall, said series circuit comprising semiconductor means, a first quarter-wave transmission line portion having a predetermined characteristic impedance, a second quarter-wave transmission line portion having a characteristic impedance large compared to that of said first quarter-wave transmission line portion, means for transferring high-frequency energy with respect to said cavity.
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6. An oscillator for generating high-frequency energy comprising semiconductor means, means coupled across said semiconductor means for biasing said latter means to its negative resistance state, resonant circuit means connected across said semiconductor means, said biasing means including first and second quarter-wave transmission line portions, said first quarter-wave transmission line portion being joined at one of its ends to resistive means encompassed in part by said second quarter-wave transmission line portion, said resistive means being connected to the body of said second quarter-wave transmission line adjacent said semiconductor means, means for abstracting high-frequency energy from said oscillatoR.
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7. Apparatus defined in claim 6 wherein said means for abstracting high-frequency energy from said oscillator comprises capacitive coupling plate means coupled to the electric field in the vicinity of the adjacent ends of said first and second quarter-wave transmission line portions.
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8. In a high-frequency device, cavity resonator means, said cavity resonator means including at least one high-frequency current-conducting wall, said wall being coupled to at least one series circuit, said series circuit comprising semiconductor means with first and second terminals respectively attached at said first terminal to said wall and at said second terminal to a quarter-wave transmission line portion of predetermined characteristic impedance, a second quarter-wave transmission line portion having first and second terminals and having a characteristic impedance substantially greater than said predetermined characteristic impedance, said second quarter-wave transmission line portion being coupled at a first terminal to at least one of said series circuits, plate means capacity-coupled to said cavity resonator for forming a bypass condenser for high-frequency currents, said second terminal of said second quarter-wave transmission line portion being conductively attached to said plate means, means for transferring high-frequency energy with respect to said cavity.
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9. In a high-frequency device according to claim 8, the structure in which said quarter-wave transmission line portion of predetermined characteristic impedance is oriented substantially at right angles to said second quarter-wave transmission line portion.
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10. In a resonator device, a cavity defining means having walls adapted for conducting high-frequency currents, at least a portion of one of said conducting walls being capacity coupled to said currents, series circuit means connected between said walls and said wall portion, said series circuit means including semiconductor means having a negative resistance characteristic, and at least first and second quarter-wave transmission line portions having substantially different characteristic impedances with respect to each other, and having high conductivity for high-frequency currents, and high-frequency means coupled to said cavity for transferring energy.
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11. In apparatus of the kind described in claim 10 wherein said first quarter-wave transmission line portion has a predetermined diameter, said second quarter-wave transmission line portion has a larger diameter than said predetermined diameter, said first quarter-wave transmission line portion is electrically connected to a portion of a first end of said second quarter-wave transmission line portion, a second portion of said first end being formed of material for converting unwanted high-frequency energy into heat.
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12. Apparatus of the type set forth in claim 11, wherein the depth of material for converting unwanted high-frequency energy into heat is substantially greater than the skin depth for the frequency of any undesired signal present.
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13. In apparatus of the kind described in claim 10, wherein said first quarter-wave transmission line portion has a predetermined characteristic impedance, said first quarter-wave transmission line portion has at least one end face, said face has a substantially concentric bore therewithin, said bore encompasses a cylindrical resistor with first and second terminal leads and first and second faces, said first terminal lead is soldered within said bore to said first quarter-wave transmission line portion, said first face of said resistor lies within said bore, said second face of said resistor lies in substantially the same plane as said end face of said first quarter-wave transmission line portion, said second terminal lead forms said second quarter-wave transmission line having a characteristic impedance differing from that of said predeterMined characteristic impedance.
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14. A high-frequency device according to claim 10, wherein said means for transferring high-frequency energy with respect to said cavity comprises a transmission line passing through a wall of said cavity, said transmission line includes inner and outer high-frequency conductors supported in coaxial relation and said inner conductor supports capacitive coupling plate means adjacent the junction common to said first and second quarter-wave transmission line portions.
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15. A device of the kind described in claim 14, wherein the effective capacitive coupling between said capacitive coupling plate means and said junction between said first and second quarter-wave transmission line portions is adjusted below a predetermined value so that the effective loading on said semiconductor element is represented by a positive resistance smaller than the net negative resistance of said semiconductor element permitting the generation of high-frequency oscillations within said cavity.
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16. A device of the kind described in claim 14 wherein the effective capacitive coupling between said capacitive coupling plate means and said junction between said first and second quarter-wave transmission line portions is adjusted above a predetermined value so that the effective loading on said semiconductor element is represented by an equivalent positive resistance larger than the net negative resistance of said semiconductor element such that high-frequency signals coupled into said cavity from the exterior are amplified.
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17. A high-frequency device having a hollow body said body having at least first and second internal walls, said walls being adapted to conduct high-frequency currents, said first wall being capacitively coupled at least to said second wall, a quarter-wave transmission line portion of a first characteristic impedance having first and second ends, coupled at its first end to said first wall, at least one quarter-wave transmission line portion of a second characteristic impedance having first and second ends and coupled at its first end to said second end of said first quarter-wave transmission line, said quarter-wave transmission line portion of second characteristic impedance being coupled at its said second end to a semiconductor element, said semiconductor element being supported by said second wall, means for abstracting high-frequency energy from said hollow body.
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18. A high-frequency device having a hollow body said body having at least first and second internal walls, said walls being adapted to permit conduction of high-frequency currents, said first wall being capacitively coupled at least to said second wall, a quarter-wave transmission line portion of a first characteristic impedance and having first and second ends coupled at its first end to said first wall, an array of series circuits coupled in parallel to said second end of said transmission line portion of first characteristic impedance, said series circuits each comprising a second quarter-wave transmission line portion and a semiconductor element, said semiconductor elements being conductively mounted on said second wall, means for abstracting energy from within said hollow body.
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19. Apparatus as in claim 18, wherein said series circuits form substantially symmetrical radial arms lying in a common plane substantially at right angles to said transmission line portion of first characteristic impedance.
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20. Apparatus as in claim 18, wherein said second wall is cylindrical in shape.
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21. Apparatus as in claim 19, wherein said means for abstracting high-frequency energy comprises capacitive coupling means symmetrically placed adjacent the said common plane of radial arms.
Specification