Abstract: A power feedforward amplifier uses integral cavities to provide RF isolation between subcircuits of the power amplifier. The chassis includes a main chassis body and a lid structure adapted to couple with the chassis body and define the subcircuit cavities. The inner lid includes an amplifier dividing wall and interstage walls adapted to isolate the main and error amplifier subcircuits of the feedforward power amplifier and further to isolate individual components of the subcircuits. In one embodiment, the amplifier subcircuits are mounted on a single circuit board and isolated from each other by the dividing wall. A delay line subcircuit portion is integral with the main chassis body and is coupled beneath the error amplifier subcircuit to contain and electromagnetically shield a delay line filter subcircuit while providing direct connection with the error amplifier.

Abstract: An antenna has multiple arrays of radiating elements and includes a plurality of single channel power amplifiers, with each amplifier electrically connected with an array. The radiating elements of the arrays are interleaved so that radiation from the arrays combines at a distance from the antenna.

Abstract: An automatic gain compensation circuit for actively adjusting the gain of an amplifier caused by in-loop and/or out-of-loop influences on system gain. Two matched RF detectors convert pre- and post-amplified signals to input and output voltages representative of the power of the RF signals. A gain control circuit which may include a Digital Analog Converter (DAC) utilizes an offset voltage that is weighted along with the input and output voltages to produce an error voltage. The error voltage is used to drive a voltage-controlled attenuator within the amplification path. Operational amplifiers may be used in the weighting circuits for weighting the input, output, and offset voltages in order to prevent loading of the RF detector outputs and to obtain rapid settling time. During amplifier operation, the offset voltage is adjusted by a processing unit to compensate for gain changes in the amplifier due to out-of-loop temperature-related influences on system gain.

Abstract: A feed forward power amplifier system and method identify active channels across a frequency band to suppress unwanted intermodulation distortion (IMD) products in a communications signal such as a single- or multi-carrier communications signal. A scanning receiver identifies at least one active channel in a frequency band, and identifies at least one portion of the frequency band likely to include IMD products based upon the identified active channel(s). Based upon the identified portion of the frequency band, IMD products are suppressed from the communications signal, e.g., by controlling the magnitude and/or phase of a suppression signal mixed with the communications signal.

Abstract: A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products.

Abstract: A power feedforward amplifier uses integral cavities to provide RF isolation between subcircuits of the power amplifier. The chassis includes a main chassis body and a lid structure adapted to couple with the chassis body and define the subcircuit cavities. The inner lid includes an amplifier dividing wall and interstage walls adapted to isolate the main and error amplifier subcircuits of the feedforward power amplifier and further to isolate individual components of the subcircuits. In one embodiment, the amplifier subcircuits are mounted on a single circuit board and isolated from each other by the dividing wall. A delay line subcircuit portion is integral with the main chassis body and is coupled beneath the error amplifier subcircuit to contain and electromagnetically shield a delay line filter subcircuit while providing direct connection with the error amplifier.