Patent US3728731A successfully refreshed from Google Patents.
US3728731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-function antenna coupler
Assignee: Motorola Solutions Inc
•
Filing: 1971-07-02
•
Granted: 1973-04-17
•
Expires: 1991-07-02
Abstract
Abstract The antenna coupling circuit facilitates simultaneous reception and transmission of information carrying radio signals through a common antenna. A single filter having a plurality of helical resonator sections forms the harmonic filter of the transmitter, the preselector of the receiver, and a duplexer for connecting both the transmitter and receiver to a single antenna. A first plurality of the helical resonator sections are connected between the antenna and the input stage of a receiver which passes the band of frequencies to be received while reflecting the frequencies to be transmitted. A second plurality of helical resonator sections are connected between the output of a transmitter and the antenna which passes the frequencies to be transmitted while reflecting the frequencies to be received. The coupling between individual helical resonators is arranged to discriminate against frequencies higher than the passband. All of the cells of the filter circuit are mechanically connected together to form an integral compact structure.
Inventors
- 👤 C Choi
- 👤 Ghay M Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:47
CPC Classifications
H; H03; H03H; H03H7/00; H03H7/46
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
255 words
Filter apparatus for selectively coupling signals from an antenna to an input stage of a radio receiver operating on a first frequency band and from an output stage of a transmitter operating on a second frequency band to the antenna, the filter apparatus including in combination: a conductive housing including a plurality of conductive enclosures and helical windings in each of said enclosures forming a plurality of helical resonators; a first group of said helical resonators being tuned to the first frequency band to form a receiver preselector filter having an output terminal adapted to be connected to the input stage of the radio receiver for selecting signals applied thereto; a second group of said helical resonators being tuned to the second frequency band to form a transmitter harmonic filter having an input terminal adapted to be connected to the output stage of the transmitter for selecting only the desired components of the signal therefrom; an antenna terminal on said housing adapted to be connected to the antenna; first circuit means coupling said winding of said receiver filter to said antenna terminal whereby the receiver filter selects signals of the first frequency band and applies tHe same to the receiver stage and rejects signals of the second frequency band; and second circuit means coupling said winding of said transmitter filter to said antenna terminal whereby the transmitter filter selects signals of the second frequency band from the transmitter stage and applies the same to the antenna terminal and rejects signals of the first frequency band.
Claim 2
Dependent Claim
255 words
Filter apparatus for selectively coupling signals from an antenna to an input stage of a radio receiver operating on a first frequency band and from an output stage of a transmitter operating on a second frequency band to the antenna, the filter apparatus including in combination: a conductive housing including a plurality of conductive enclosures and helical windings in each of said enclosures forming a plurality of helical resonators; a first group of said helical resonators being tuned to the first frequency band to form a receiver preselector filter having an output terminal adapted to be connected to the input stage of the radio receiver for selecting signals applied thereto; a second group of said helical resonators being tuned to the second frequency band to form a transmitter harmonic filter having an input terminal adapted to be connected to the output stage of the transmitter for selecting only the desired components of the signal therefrom; an antenna terminal on said housing adapted to be connected to the antenna; first circuit means coupling said winding of said receiver filter to said antenna terminal whereby the receiver filter selects signals of the first frequency band and applies tHe same to the receiver stage and rejects signals of the second frequency band; and second circuit means coupling said winding of said transmitter filter to said antenna terminal whereby the transmitter filter selects signals of the second frequency band from the transmitter stage and applies the same to the antenna terminal and rejects signals of the first frequency band.
Claim 3
Dependent Claim
32 words
The filter apparatus of claim 1 wherein said first circuit means includes capacitor means having a first plate connected to said antenna terminal and a second plate connected to said receiver filter.
Claim 4
Dependent Claim
32 words
The filter apparatus of claim 1 wherein said second circuit means includes capacitor means having a first plate connected to said antenna terminal and a second plate connected to said transmitter filter.
Claim 5
Dependent Claim
163 words
The filter apparatus of claim 1 further including: first capacitor means having a first plate formed by a portion of said winding of said receiver filter, a dielectric formed by a first insulating member which is mechanically connected to said winding of said receiver filter, and a second plate formed by a first conductive member having first and second ends, said first end being connected to said first insulating member and said second end being connected to said antenna terminal; and second capacitor means having a first plate formed by a portion of said winding of said transmitter filter, a dielectric formed by a second insulating member which is mechanically connected to said winding of said transmitter filter, and a second plate formed by a second conductive member having first and second ends, said first end of said second conductive member being connected to said second insulating member and said second end of said second conductive member being connected to said antenna terminal.
Claim 6
Dependent Claim
186 words
The filter apparatus of claim 1 wherein said receiver filter includes a plurality of cooperating helical resonators which tend to have a spurious passband, each of said resonators having a helical coil with first and second ends and a longitudinal axis, and a housing member enclosing said helical coil which is formed by four conductive sidewalls and first and second conductive end walls, said longitudinal axis of each of said coils being perpendicular to said first and second conductive end walls; said resonators being juxtapositioned with respect to each other so that said housing member of each resonator has a common sidewall with the housing member of a cooperating resonator; said first end walls of said resonators being formed by a single integral conductive member; means electrically connecting said first end of each of said coils to said integral conductive member; and each of said common sidewalls having an aperture formed therein, said apertures being located adjacent to said second ends of said coils to facilitate predominantly capacitive coupling between said adjacent cooperating resonators to provide attenuation to signals having frequencies lying within said spurious passband.
Claim 7
Dependent Claim
186 words
The filter apparatus of claim 1 wherein said transmitter filter includes a plurality of cooperating helical resonators which tend to have a spurious passband, each of said resonators having a helical coil with first and second ends and a longitudinal axis, and a housing member enclosing said helical coil which is formed by four conductive sidewalls and first and second conductive end walls, said longitudinal axis of each of said coils being perpendicular to said first and second conductive end walls; said resonators being juxtapositioned with respect to each other so that said housing member of each resonator has a common sidewall with the housing member of a cooperating resonator; said first end walls of said resonators being formed by a single integral conductive member; means electrically connecting said first end of each of said coils to said integral conductive member; and each of said common sidewalls having an aperture formed therein, said apertures beIng located adjacent to said second ends of said coils to facilitate predominantly capacitive coupling between said adjacent cooperating resonators to provide attenuation to signals having frequencies lying within said spurious passband.
Claim 8
Dependent Claim
215 words
The filter apparatus of claim 1 wherein each of said resonators has a helical coil with first and second ends, a coil form for supporting said coil and having first and second ends and an aperture extending from said second end into said coil form, and a housing member formed by four conductive sidewalls and first and second conductive end walls; said resonators of said receiver filter being juxtapositioned so that said housing members thereof have common intermediate sidewalls; said resonators of said transmitter filter being juxtapositioned so that said housing members thereof also have common intermediate sidewalls; said first end walls of said housing members of each of said filters being formed by a first integral conductive member, means electrically connecting said first ends of said coils to said first conductive member; said second end walls of said housing members of each of said filters being formed by a second integral conductive member having a surface located in a plane which is parallel to and adjacent to said second ends of said coil forms; and a plurality of tuning means each extending through said second conductive member into said aperture of one of said coil forms, said plurality of tuning means facilitating simultaneous adjustment of said resonant frequencies of said receiver and transmitter filters.
References Cited (Backward Citations)
US3293644A
Cited
US3656162A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |