US3842370A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coaxial trapatt oscillator operable at a fixed frequency and at a high efficiency
Assignee: Raytheon Co
•
Filing: 1973-02-22
•
Granted: 1974-10-15
•
Expires: 1993-02-22
Abstract
Abstract Disclosed is an improved and highly efficient coaxial TRAPATT oscillator and method for rapidly tuning same. The oscillator includes a TRAPATT diode connected directly between an outer coaxial conductor and a cylindrical quarter wave impedance transformer, and the transformer is in turn coaxially mounted directly between the TRAPATT diode and an inner coxial conductor of the oscillator. An end wall of the cylindrical impedance transformer is closely adjacent to the TRAPATT diode and it forms with the outer conductor a relatively large capacitance necessary for handling the TRAPATT diode displacement currents. Additionally, the geometry of the impedance transformer may be varied to control both this capacitance as well as the transformer impedance, ZT, and the latter in turn determines the optimum delay angle for the oscillator. The impedance transformer provides, among other things, the three functions of: (1) impedance matching the TRAPATT diode to the coaxial oscillator circuitry, (2) providing Saalbach; Herman Karl relatively large gap capacitance, Cg, necessary for handling TRAPATT diode displacement currents, and (3) controlling the optimum delay angle, theta d, of the oscillator. The geometry and location of the step transformer with respect to the TRAPATT diode and the above coaxial conductors greatly improve the tunability of the oscillator.
Inventors
- 👤 T Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:16
CPC Classifications
H; H03; H03B; H03B9/00; H03B9/12; H03B9/14; H03B9/145; H03B2009/126; H03B2201/00; H03B2201/01; H03B2201/014; H03B2201/015
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
220 words
An improved TRAPATT oscillator including in combination: a. an inner conductor surrounded by a hollow outer conductor, said conductors being mounted in a predetermined spaced-apart relationship, b. a TRAPPATT diode electrically connected to said outer conductor, c. an impedance matching step transformer connected directly between said TRAPPATT diode and said inner conductor, said step transformer being substantially coaxial with said inner conductor and having a radial dimension thereof greater than the corresponding radial dimension of said inner conductor, said step transformer being operable to match the impedance of said TRAPATT diode with that of an oscillator load, as well as establish an optimum delay angle, theta d, for the shock wave generated by said TRAPATT diode, said step transformer further establishing a relatively high gap capacitance, Cg, for handling large displacement currents flowing in said TRAPATT diode, and d. a plurality of tuning stubs slidably mounted between said inner and outer conductors for establishing a low pass filter section of said oscillator, the positions of said stubs establishing a particular value of impedance seen by said TRAPATT diode which corresponds to a preselected frequency for said oscillator when operating at a maximum DC-RF conversion efficiency, said efficiency determined by the diode''s internal electrical characteristics, the impedance of said step transformer, said gap capacitance Cg and said delay angle theta d.
Claim 2
Dependent Claim
220 words
An improved TRAPATT oscillator including in combination: a. an inner conductor surrounded by a hollow outer conductor, said conductors being mounted in a predetermined spaced-apart relationship, b. a TRAPPATT diode electrically connected to said outer conductor, c. an impedance matching step transformer connected directly between said TRAPPATT diode and said inner conductor, said step transformer being substantially coaxial with said inner conductor and having a radial dimension thereof greater than the corresponding radial dimension of said inner conductor, said step transformer being operable to match the impedance of said TRAPATT diode with that of an oscillator load, as well as establish an optimum delay angle, theta d, for the shock wave generated by said TRAPATT diode, said step transformer further establishing a relatively high gap capacitance, Cg, for handling large displacement currents flowing in said TRAPATT diode, and d. a plurality of tuning stubs slidably mounted between said inner and outer conductors for establishing a low pass filter section of said oscillator, the positions of said stubs establishing a particular value of impedance seen by said TRAPATT diode which corresponds to a preselected frequency for said oscillator when operating at a maximum DC-RF conversion efficiency, said efficiency determined by the diode''s internal electrical characteristics, the impedance of said step transformer, said gap capacitance Cg and said delay angle theta d.
Claim 3
Dependent Claim
58 words
The oscillator defined in claim 1 wherein said impedance matching transformer is a step transformer of cylindrical shape and with an impedance, ZT, which is proportional to its diameter, whereby said diameter may be controlled to in turn closely control Cg as well as the optimum delay angle, theta d, for said oscillator, which is dependent upon ZT.
Claim 4
Dependent Claim
76 words
The oscillator defined in claim 2 wherein the size of the cylindrical body forming said step transformer is selected to establish the gap capacitance, Cg, proportional to A/d, where A is the area of the end wall of the cylindrical body and d is the gap spacing between said end wall and the outer conductor of said oscillator; the diameter of said cylindrical body also chosen to control and establish said optimum delay angle, theta d.
Claim 5
Dependent Claim
58 words
The oscillator defined in claim 3 wherein the step transformer impedance, ZT, is controlled by the ratio b/a, where b is the spacing between the longitudinal axis of said cylindrical body and said outer conductor and a is the radius of said cylindrical body, whereby the dimension b may be varied to independently control ZT without varying Cg.
Claim 6
Dependent Claim
186 words
A microwave coaxial oscillator having inner and outer substantially coaxial conductors operative for coupling microwave power to an external load, said oscillator including: a. a high frequency negative resistance diode mounted on a header which is electrically connected to said outer coaxial conductor, said header having an end wall thereof forming one plate of a gap capacitance for said diode, b. an impedance matching step transformer electrically connected directly between said diode and said inner conductor of said oscillator and having an end wall which forms, with the end wall of said header, a parallel plate capacitor with a gap capacitance, Cg, for conducting relatively large displacement currents from said diode, and c. a plurality of tuning stubs slidably mounted between said inner and outer conductors for controlling the impedance seen by said diode, said oscillator may be frequency tuned by the movement of said stubs to ensure that said oscillator operates at a preselected frequency after the size of said transformer has been selected to provide the optimum delay angle and optimum conversion efficiency for said diode and said oscillator corresponding to said preselected frequency.
Claim 7
Dependent Claim
186 words
A microwave coaxial oscillator having inner and outer substantially coaxial conductors operative for coupling microwave power to an external load, said oscillator including: a. a high frequency negative resistance diode mounted on a header which is electrically connected to said outer coaxial conductor, said header having an end wall thereof forming one plate of a gap capacitance for said diode, b. an impedance matching step transformer electrically connected directly between said diode and said inner conductor of said oscillator and having an end wall which forms, with the end wall of said header, a parallel plate capacitor with a gap capacitance, Cg, for conducting relatively large displacement currents from said diode, and c. a plurality of tuning stubs slidably mounted between said inner and outer conductors for controlling the impedance seen by said diode, said oscillator may be frequency tuned by the movement of said stubs to ensure that said oscillator operates at a preselected frequency after the size of said transformer has been selected to provide the optimum delay angle and optimum conversion efficiency for said diode and said oscillator corresponding to said preselected frequency.
Claim 8
Dependent Claim
42 words
The oscillator defined in claim 5 wherein said diode is a TRAPATT diode with a fundamental frequency, omega o, in radians per second, which is the preselected frequency of said oscillator when said oscillator is operating at a maximum DC-RF conversion efficiency.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |