US5164686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High-frequency oscillator having a field-effect transistor with a stepwise increasing active layer carrier concentration
Assignee: Sumitomo Electric Industries Ltd
•
Filing: 1991-11-15
•
Granted: 1992-11-17
•
Expires: 2011-11-15
Abstract
Abstract This invention is a high-frequency oscillator including a MESFET, wherein a GaAs MESFET, in which the doping profile of an active layer has a pulse-doped structure, is used as the MESFET. Since the GaAs MESFET is formed to have the pulse-doped structure, the change in transconductance with respect to the change in gate resistance remains constant at gate voltages within a predetermined range. When the gate voltage is set to be a voltage within this predetermined range, a capacitance change with respect to a gate voltage across a gate and a source is reduced. FM noise proportional to the magnitude of this capacitance change is reduced. Accurate information transmission is not interfered with unlike in conventional arrangements.
Inventors
- 👤 Nobuo Shiga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:33
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/18; H03B5/1864; H03B5/187; H03B5/1876; H03B2200/00; H03B2200/0014; H03B2200/0028; H03B2200/003; H03B2200/0058; H03B2200/006; H03B2200/0088; H03B2200/009; H03B2202/00; H03B2202/02; H03B2202/025; H03B2202/027; H03B2202/06; H03B5/1841; H03B5/1847; H03B5/1852
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
47 words
A high-frequency oscillator comprising: a Schottky barrier field-effect transistor, and a resonator having an output connected to said field-effect transistor, said field-effect transistor being formed of a GaAs semiconductor, and a carrier concentration of an active layer of said field-effect transistor increasing stepwise at a predetermined depth.
Claim 2
Dependent Claim
47 words
A high-frequency oscillator comprising: a Schottky barrier field-effect transistor, and a resonator having an output connected to said field-effect transistor, said field-effect transistor being formed of a GaAs semiconductor, and a carrier concentration of an active layer of said field-effect transistor increasing stepwise at a predetermined depth.
Claim 3
Dependent Claim
38 words
An oscillator according to claim 1, further comprising means for setting a gate voltage of said field-effect transistor within a range in which a change in transconductance with respect to a change in the gate voltage remains constant.
Claim 4
Dependent Claim
44 words
An oscillator according to claim 1, wherein a gate of said Schotty barrier field effect transistor is doped to electrically connect with the resonator, and an output of said high frequency oscillator is provided in a drain of said Schottky barrier field effect transistor.
Claim 5
Dependent Claim
13 words
An oscillator according to claim 3, wherein the resonator comprises a dielectric resonator.
Claim 6
Independent Claim
90 words
A method of reducing FM noise in a high-frequency oscillator which comprises a Schottky barrier field-effect transistor, and a resonator which has an output connected to said field-effect transistor, said field-effect transistor being formed of a GaAs semiconductor, and a carrier concentration of an active layer of said field-effect transistor increasing stepwise at a predetermined depth, said method comprising the step of setting the gate voltage of said field-effect transistor within a range in which a change in transconductance with respect to a change in the gate voltage remains constant.
Claim 7
Independent Claim
90 words
A method of reducing FM noise in a high-frequency oscillator which comprises a Schottky barrier field-effect transistor, and a resonator which has an output connected to said field-effect transistor, said field-effect transistor being formed of a GaAs semiconductor, and a carrier concentration of an active layer of said field-effect transistor increasing stepwise at a predetermined depth, said method comprising the step of setting the gate voltage of said field-effect transistor within a range in which a change in transconductance with respect to a change in the gate voltage remains constant.
References Cited (Backward Citations)
US4707669A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-11-17 | 1996-05-18 | 1996-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-17 | 2000-05-18 | 2000-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-17 | 2004-05-18 | 2004-11-17 | $7700.00 | Window Closed / Lapsed |