US4845389A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Very high frequency mixer
Assignee: US Philips Corp
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Filing: 1988-03-01
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Granted: 1989-07-04
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Expires: 2008-03-01
Abstract
Abstract A mixer of the two-transistor type (T 1 , T 2 ) arranged in series by a source S 2 and a drain D 1 . A Gate G 1 receives a radio frequency signal RF and a gate G 2 a local oscillator signal L0. Matching networks R 1 and R 2 are provided for the respective signals RF and L0. One element of the network R 3 positioned at the output (drain D 2 of the transistor T 2 ) restores a short-circuit at the frequency f L0 of the local oscillator. The instability of the input G 2 of the transistor T 2 is compensated for by an inductor element L inserted between the junction point of the source S 2 and the drain D 1 and the common-mode pole.
Inventors
- 👤 Ramesh Pyndiah
- 👤 Patrice Gamand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:24
CPC Classifications
H; H03; H03D; H03D9/00; H03D9/06; H03D9/0658; H03D9/0675; H03D2200/00; H03D2200/0001; H03D2200/0025; H03D2200/0027; H03D7/00; H03D7/12; H03D7/125
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
A very high frequency mixer comprising a first and a second field effect transistor, one of the transistors being intended to receive at its gate a local oscillator signal and the other transistor a radio-frequency input signal, the first transistor having a source connected to a first supply voltage pole, and a drain connected at a junction point to a source of the second transistor, and a drain of the second transistor being connected to a second supply voltage pole via a resistor, characterized in that the drain of the second transistor is charged by a circuit element realizing a short-circuit at the frequency of the local oscillator signal, and in that the mixer further comprises an inductor element inserted between the junction point and a common-mode pole, the inductor element being selected such as to compensate for drain-source capacitances of the two transistors and thus to stabilize the input at the gate of a second transistor.
Claim 2
Dependent Claim
157 words
A very high frequency mixer comprising a first and a second field effect transistor, one of the transistors being intended to receive at its gate a local oscillator signal and the other transistor a radio-frequency input signal, the first transistor having a source connected to a first supply voltage pole, and a drain connected at a junction point to a source of the second transistor, and a drain of the second transistor being connected to a second supply voltage pole via a resistor, characterized in that the drain of the second transistor is charged by a circuit element realizing a short-circuit at the frequency of the local oscillator signal, and in that the mixer further comprises an inductor element inserted between the junction point and a common-mode pole, the inductor element being selected such as to compensate for drain-source capacitances of the two transistors and thus to stabilize the input at the gate of a second transistor.
Claim 3
Dependent Claim
36 words
A mixer as claimed in claim 1, wherein the first transistor is intended to receive at its gate the radio-frequency signal and the second transistor is intended to receive at its gate the local oscillator signal.
Claim 4
Dependent Claim
26 words
A mixer as claimed in claim 2, the gate of the first transistor comprises a circuit for matching the signal which it is intended to receive.
Claim 5
Dependent Claim
30 words
A mixer as claimed in claim 3, wherein the gate of the second transistor (T 2 ) comprises a matching circuit for the signal which it is intended to receive.
Claim 6
Dependent Claim
98 words
A mixer as claimed in one of the preceding claims 1-4 wherein the inductor element has a value L such that: ##EQU8## with: fT 2 being the cut-off frequency at 0 dB of the second transistor, Cgs 2 being the gate source capacitor of the second transistor Cds 1 and Cds 2 being drain-source capacitors of the first and second transistors, respectively, gd 1 and gd 2 being conductances of the first and second transistors, respectively, and Cds=CDs 1 +Cds 2 , gd=gd 1 +gd 2 ω.sub. = π F 0 F o =the highest local oscillator frequency.
Claim 7
Dependent Claim
52 words
A mixer as claimed in claim 5, wherein the inductor element L is chosen such as to realize a bandpass filter whose central frequency is situated substantially within the useful receiver band, so as to filter out noise situated in the intermediate-frequency band and generated by the first transistor T 1 .
Claim 8
Dependent Claim
43 words
A mixer as claimed in claim 5, wherein the inductor element has a value L in the neighborhood of LO with: ##EQU9## where w RF =2πF RF , F RF denoting the frequency of the input signal and F RF =F LO .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-03 | 1993-01-02 | 1993-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-03 | 1997-01-02 | 1997-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-03 | 2001-01-02 | 2001-07-04 | $7700.00 | Window Closed / Lapsed |