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 to 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.

Equal power amplifier system for active phase array antenna and method of arranging same

A novel 8-way divider/combiner using TM/sub 010/- and TM/sub 020/ -mode cavities was developed. This divider/combiner has an insertion loss of 0.2 dB and a bandwidth of 600 MHz in the 6-GHz communications band. For broadening the operating bandwidth of the divider/combiner, two techniques of double cavities and tight coupling are described. Degradation of power-combining efficiency is also discussed when input signals into a power combiner have variations in amplitude and phase. By using this divider/combiner, an experimental 6-GHz 80-W GaAs FET amplifier with a combining efficiency of 85 percent was demonstrated to investigate the feasibility of a solid-state high-power amplifier.

A 6-GHz 80-W GaAs FET Amplifier with a TM-Mode Cavity Power Combiner

A broadband, monolithic integrated-circuit power divider/combiner circuit utilizing gallium arsenide field-effect transistors configured as distributed amplifiers Two distributed amplifiers include a common merged transmission line element which divides/combines the input signal(s)

Power divider/combiner circuit

A novel 8-way divider/combiner using TM010- and TM020-mode cavities was developed, with an insertion loss of 0.2 dB and a bandwidth of 600 MHz at 6 GHz. An 80-W broadband GaAs FET amplifier with combining efficiency of 85 percent was successfully demonstrated using this power divider/combiner.

A 6-GHz 80-W GaAs FET Amplifier with TM-Mode Cavity Power Combiner

An apparatus (20) for use as an amplifier has a transistor (26) for providing signal amplification, a heat pipe or circulated fluid heat sink (22) and a thermal interface device (24) for providing mechanical and thermal connection between the transistor (26) and the heat sink (22). In use, to facilitate efficient transfer of heat/thermal energy from the transistor (26) to the heat sink (22), the plate (24) is provided between the heat sink (22) and the transistor (26). The plate (24) connects the heat sink (22) to the transistor (26) and provides a thermal conduit therebetween.

Apparatus and method for thermal interfacing

A high power GaAs FET amplifier with an output power of 40 watts at 4.5 GHz has been developed. Power conbining loss of 1.1 dB was investigated and cooling system using heat pipe was developed.

M. Takagi

Papers

A 4.5 Ghz 40 Watt Gaas Fet Amplifier