Equal power amplifier system for active phase array antenna and method of arranging same
First Claim
1. A transmit subsystem for use with a microwave antenna system having an array of radiating elements, comprising:
- beam-forming network means for producing, from at least one transmit signal, a plurality of output signals having a predetermined relationship relative to one another which defines a distribution function desired for driving the array of radiating elements to produce at least one microwave beam having selected characteristics, said beam-forming network means including(1) at least one first line for carrying the transmit signal, and(2) a set of second lines spaced from one another and operatively disposed at an angle to and crossing the first line so as to define cross-over points therewith, each of the second lines being coupled to the first line at the cross-over points such that a portion of the electromagnetic energy of the transmit signal carried by the first line is transferable to each of the second lines, each of the second lines having an output adapted to be placed in electromagnetic communication with the array, the first line having first and second portions spaced apart from one another and respectively defining first and second levels displaced from one another, the set of second lines having first and second subsets of second lines respectively arranged adjacent to said first and second levels and respectively associated with the first and second portions of the first line, such that the first subset of second lines is coupled to the first portion of the first line, and the second subset of second lines is coupled to the second portion of the first line;
amplifying means for amplifying the plurality of output signals before the output signals are applied to the array, the amplifying means including at least a pair of first power amplifiers for simultaneously amplifying a selected first pair of the output signals having substantially unequal signal strength, means for dividing the selected pair of signals between the amplifiers such that the amplifiers substantially equally share the task of amplifying the selected pair of signals, said amplifying means including a plurality of such pairs of first power amplifiers, each such pair being arranged for simultaneously amplifying a distinct selected pair of the output signals; and
means for combining signals output by the amplifiers to form a first pair of amplified signals which each directly correspond to a respective one of the first pair of output signals.
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Accused Products
Abstract
An equal power amplifier system (100) for amplifying a plurality of signals for transmission by an active phase array antenna (20), and a compact plural level beam-forming network (98) for forming a plurality of such signals, for example on excitation patterns for frequency scanned virtual beams, are disclosed. The amplifier system uses at most only a few sizes of power amplifiers (130, 134) to amplify efficiently numerous signals having significantly different amplitudes. This is accomplished by distributing the task of amplifying signal pairs (Ai, Bi) composed of one large amplitude signal and one small amplitude signal to an equal power amplifying apparatus (130; 230), which includes two hybrid couplers (236, 238) and two equally sized power amplifiers (232, 234). The first hybrid coupler (236) divides the two signals (Ai, Bi) for input into the two power amplifiers. The second hybrid coupler (238) receives the intermediate amplified signals from the power amplifiers and through constructive and destructive interference produces amplified output signals (Ai *, Bi *) corresponding to the input signals. Also disclosed is a method for properly selecting pairs of signals from an amplitude distribution (200; 202) for application of such equal power amplifying apparatuses of the amplifier system in order to operate the power amplifiers therein at or near peak efficiency. The beam-forming network (98) is arranged on two levels to simplify interconnection of the selected pairs of outputs of its line summers (176) for input into the equal power amplifier system. The amplifier system and beam-forming network may be used together, for example, in the transmit antenna system of a geosynchronous satellite (10) or mobile earth station.
52 Citations
33 Claims
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1. A transmit subsystem for use with a microwave antenna system having an array of radiating elements, comprising:
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beam-forming network means for producing, from at least one transmit signal, a plurality of output signals having a predetermined relationship relative to one another which defines a distribution function desired for driving the array of radiating elements to produce at least one microwave beam having selected characteristics, said beam-forming network means including (1) at least one first line for carrying the transmit signal, and (2) a set of second lines spaced from one another and operatively disposed at an angle to and crossing the first line so as to define cross-over points therewith, each of the second lines being coupled to the first line at the cross-over points such that a portion of the electromagnetic energy of the transmit signal carried by the first line is transferable to each of the second lines, each of the second lines having an output adapted to be placed in electromagnetic communication with the array, the first line having first and second portions spaced apart from one another and respectively defining first and second levels displaced from one another, the set of second lines having first and second subsets of second lines respectively arranged adjacent to said first and second levels and respectively associated with the first and second portions of the first line, such that the first subset of second lines is coupled to the first portion of the first line, and the second subset of second lines is coupled to the second portion of the first line; amplifying means for amplifying the plurality of output signals before the output signals are applied to the array, the amplifying means including at least a pair of first power amplifiers for simultaneously amplifying a selected first pair of the output signals having substantially unequal signal strength, means for dividing the selected pair of signals between the amplifiers such that the amplifiers substantially equally share the task of amplifying the selected pair of signals, said amplifying means including a plurality of such pairs of first power amplifiers, each such pair being arranged for simultaneously amplifying a distinct selected pair of the output signals; and means for combining signals output by the amplifiers to form a first pair of amplified signals which each directly correspond to a respective one of the first pair of output signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. For use with a microwave antenna system of the type including an array of radiating elements for producing at least one microwave beam having a preselected beam pattern, and means for producing a plurality of transmit signals respectively having various predefined amplitudes related to said beam pattern, apparatus for amplifying said transmit signals comprising:
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a plurality of discrete amplifying network means for respectively amplifying a plurality of distinct selected pairs of said transmit signals such that the amplified transmit signals output by each amplifying network means are independent of the transmit signals intended to be amplified by other of said amplifying network means, each of said amplifying network means including first and second inputs for respectively receiving first and second transmit signals which define said pair of transmit signals, and first and second outputs for respectively delivering said pair of transmit signals to said array of radiating elements, said inputs being connected with said transmit signal producing means in a manner such that the sums of the amplitudes of the pairs of transmit signals respectively received by said plurality of said amplifying network means are essentially equal, each of said amplifying network means further including (1) means for dividing each of said first and second signals into first and second portions, (2) first amplifying means coupled with said dividing means for amplifying said first portion of said first transmit signals and said second portion of said second transmit signal, thereby producing a first intermediate signal, (3) second amplifying means coupled with said dividing means for amplifying said first portion of said second transmit signal and said second portion of said first transmit signal, thereby producing a second intermediate signal, and (4) means coupled with said first and second amplifying means for combining said first and second intermediate signals in a manner to produce said first and second transmit signals in amplified form respectively on said first and second outputs. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. For use in a microwave antenna system of the type including an array of radiating elements for producing at least one microwave beam having a preselected beam pattern, and means for producing a plurality of transmit signals respectively having various predefined amplitudes related to said beam pattern, a method of amplifying said transmit signals, comprising the steps of:
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(A) associating said transmit signals with each other in a manner to form a plurality of distinct pairs of said transmit signals, wherein the sums of the amplitudes of the pairs of transmit signals are essentially equal; (B) separately amplifying each of said pairs of transmit signals using a plurality of separate amplification means, respectively associated with said plurality of pairs of transmit signals, wherein the amplification factors of all of said amplification means are essentially equal; (C) delivering the pairs of transmit signals amplified in step (B) to said array. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification