Two-feed full duplex transmitter/receiver for ultra small-aperture satellite communications terminal
First Claim
1. In a satellite communications terminal having an antenna dish and at least one full-duplex transmitter/receiver device, an improvement comprising:
- providing the at least one of the full-duplex transmitter/receiver device with a means for receiving signals and a separate means for transmitting signals, with said means for receiving signals including a receive feedhorn for receiving signals only and with said means for transmitting including a transmit feedhorn for transmitting signals only, with the receive and transmit feedhorns mounted in relation to the antenna dish with the receive and transmit feedhorns being spatially offset from one another.
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Abstract
The satellite communications terminal employs separate transmit and receive feedhorns, offset from one another, to achieve adequate isolation of received and transmitted signals during full duplex operation. In one implementation, described herein, the satellite communications terminal employs an ultra-small-aperture dish antenna having an aperture of about one meter. Signals are received and transmitted at Ku band wavelengths of about 12 gigahertz and 14 gigahertz respectively. For this implementation, an extended focal point zone occurs, rather than a discrete focal point. Both the receive and transmit feedhorns are positioned within the focal point zone thereby achieving adequate gain to both reception and transmission. However, the receive and transmit feedhorns are offset from one another to minimize the coupling of feedback transmission signals into the receive feedhorn. In one specific implementation, for use in transmitting signals to and receiving signals from a geosynchronous satellite, the receive feedhorn is positioned at an ideal focal point for reception to maximize the receive gain. The transmit feedhorn is offset within the focal point zone by an amount sufficient to achieve adequate isolation while also minimizing off-axis signal transmissions, which might interfere with the reception of signals by other adjacent geosynchronous satellites. For other implementations, wherein the frequencies of reception and transmission and the characteristics of the antenna dish yield significant Fresnel diffraction effects, the ideal focal points for reception and transmission may be offset from one another. In such implementations, the receive and transmit feedhorns are both positioned at their respective ideal focal points. Method and apparatus implementations of the invention are disclosed.
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Citations
40 Claims
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1. In a satellite communications terminal having an antenna dish and at least one full-duplex transmitter/receiver device, an improvement comprising:
providing the at least one of the full-duplex transmitter/receiver device with a means for receiving signals and a separate means for transmitting signals, with said means for receiving signals including a receive feedhorn for receiving signals only and with said means for transmitting including a transmit feedhorn for transmitting signals only, with the receive and transmit feedhorns mounted in relation to the antenna dish with the receive and transmit feedhorns being spatially offset from one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A satellite communications terminal comprising:
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an antenna dish; and at least one full-duplex transmitter/receiver device having a means for receiving signals and a separate means for transmitting signals, with said means for receiving signals including a receive feedhorn for receiving signals only and with said means for transmitting signals including a transmit feedhorn for transmitting signals only, with the receive and transmit feedhorns mounted in relation to the antenna dish with the receive and transmit feedhorns being spatially offset from one another. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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31. In a satellite communications terminal having an antenna dish and at least one full-duplex transmitter/receiver device having a means for receiving signals and a separate means for transmitting signals, with said means for receiving signals including a receive feedhorn for receiving signals only and with said means for transmitting signals including a transmit feedhorn for transmitting signals only, with the receive and transmit feedhorns mounted in relation to the antenna dish with the receive and transmit feedhorns being spatially offset from one another, a method of transmitting and receiving signals comprising the steps of:
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transmitting signals only through the transmit feedhorn located at a first position relative to the antenna dish, said first position being within a focal point zone of the antenna dish; and substantially simultaneously receiving signals, reflected from the antenna dish, only through the receive feedhorn located second position relative to the antenna dish, said second position also being within the focal point zone but being offset from the first position. - View Dependent Claims (32, 33, 34, 35, 36)
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37. In a satellite communications terminal having an antenna dish and a full-duplex transmitter/receiver device, an improvement comprising:
providing separate receive and transmit feedhorns to the full-duplex transmitter/receiver device, with the receive and transmit feedhorns mounted in relation to the antenna dish and with the receive feedhorn spatially offset from the transmit feedhorn with the receive feedhorn only receiving signals and the transmit feedhorn only transmitting signals. - View Dependent Claims (38)
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39. A satellite communications terminal comprising:
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an antenna dish; and a full-duplex transmitter/receiver device having separate receive and transmit feedhorns, with the receive and transmit feedhorns of the full-duplex transmitter/receiver device mounted in relation to the antenna dish and with the receive feedhorn spatially offset from the transmit feedhorn with the receive feedhorn only receiving signals and the transmit feedhorn only transmitting signals. - View Dependent Claims (40)
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Specification