Patent US2928549A successfully refreshed from Google Patents.
US4313097A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image frequency reflection mode filter for use in a high-frequency receiver
Assignee: US Philips Corp
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Filing: 1980-02-27
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Granted: 1982-01-26
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Expires: 2000-02-27
Abstract
Abstract A planar image reflection mode filter is provided for reflecting parasitic signal frequencies produced in the mixer of a receiver. The filter includes a reflecting quarter-wavelength filter and an adaptive circuit functioning to enable the transmission of desirable frequencies. A slot can be formed in the quarter-wavelength filter to enable odd-mode resonance and reduce the width of a transition frequency band lying between a reflection band and a transmission band.
Inventors
- 👤 Francois C. de Ronde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:20
CPC Classifications
H; H01; H01P; H01P1/00; H01P1/20; H01P1/201; H01P1/203; H01P1/2039; H01P7/00; H01P7/08; H01P7/082
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
201 words
A planar, image reflection mode filter for use with a receiver including an input for receiving a signal of frequency f S , a local oscillator for supplying a signal of frequency f OL , a mixer for receiving the signal of frequency f S and the signal of frequency f OL , and a planar transmission line for coupling the signals to the mixer, the filter functioning to prevent transmission of a parasitic signal having the frequency f p =2f OL -f S from the mixer to the input, said filter comprising: A. a quarter-wavelength filter for connection at one end to the planar transmission line and having a width which is at least equal to that of the transmission line and a length which is equal to one quarter of the wave length of the signal of frequency f p , the opposite end including a slot formed therein to enable odd-mode resonance in the quarter-wavelength filter; and B. an adaptive circuit for connection to the planar transmission line at substantially the same point of the parasitic signal path as the quarter-wavelength filter, said circuit functioning to enable transmission without reflection of the signal of frequency f S .
Claim 2
Dependent Claim
201 words
A planar, image reflection mode filter for use with a receiver including an input for receiving a signal of frequency f S , a local oscillator for supplying a signal of frequency f OL , a mixer for receiving the signal of frequency f S and the signal of frequency f OL , and a planar transmission line for coupling the signals to the mixer, the filter functioning to prevent transmission of a parasitic signal having the frequency f p =2f OL -f S from the mixer to the input, said filter comprising: A. a quarter-wavelength filter for connection at one end to the planar transmission line and having a width which is at least equal to that of the transmission line and a length which is equal to one quarter of the wave length of the signal of frequency f p , the opposite end including a slot formed therein to enable odd-mode resonance in the quarter-wavelength filter; and B. an adaptive circuit for connection to the planar transmission line at substantially the same point of the parasitic signal path as the quarter-wavelength filter, said circuit functioning to enable transmission without reflection of the signal of frequency f S .
Claim 3
Dependent Claim
23 words
A filter as in claim 1 where the quarter wavelength filter comprises a rectangular conductor adapted for perpendicular connection to the transmission line.
Claim 4
Dependent Claim
32 words
A filter as in claim 1 where the quarter wavelength filter comprises a circular conductor having a diameter equal to one quarter of the wavelength associated with the frequency f p .
Claim 5
Dependent Claim
25 words
A filter as in claim 1 where the interior of the slot is occupied by a conducting surface which is insulated from the quarter-wavelength filter.
Claim 6
Dependent Claim
47 words
A filter as in claim 1, 2, 3 or 4, where the adaptive circuit comprises a rectangular conductor adapted for connection along its total length to the transmission line, said circuit having a length equal to three-eighths of the wave-length associated with the frequency f S .
Claim 7
Dependent Claim
46 words
A filter as in claim 1, 2, 3 or 4, where the adaptive circuit comprises a rectangular conductor adapted for perpendicular connection to the transmission line, said circuit having a capacitance which corrects for the inductance of the quarter-wavelength filter at the frequency f S .
Claim 8
Dependent Claim
46 words
A filter as in claim 1, 2, 3 or 4 where the adaptive circuit comprises a rectangular conductor adapted for perpendicular connection to the transmission line, said rectangular conductor widening into a second rectangular conductor to provide a series arrangement of an inductor and a capacitor.
Claim 9
Dependent Claim
46 words
A filter as in claim 1, 2, 3 or 4 where the adaptive circuit comprises a rectangular conductor adapted for prependicular connection to the transmission line, said rectangular conductor widening into a semi circular conductor to provide a series arrangement of an inductor and a capacitor.
Claim 10
Dependent Claim
49 words
A filter as in claim 1, 2, 3 or 4 where the adaptive circuit comprises two rectangular conductors for perpendicular connection to the transmission line at a distance from one another which is equal to one eighth of the wave length associated with the frequency of f S .
References Cited (Backward Citations)
US3688225A
Cited
US3678433A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |