Abstract: A system may include a first IQ modulator configured to: based on an I and a Q, produce a zero to ninety degree variable phase shifted output signal that changes relative to an input envelope of an RF drive waveform of the RF drive. The system may include a first amplifier path configured to: output a first phase modulated signal. The system may include a second IQ modulator configured to: based on the I and the ?Q, produce a zero to negative ninety degree variable phase shifted output signal that changes relative to the input envelope. The system may include a second amplifier path configured to: output a second phase modulated signal, wherein the second phase modulated signal is complementary to the first phase modulated signal. The system may include a vector generator configured to: generate the Q and the ?Q for the first and second IQ modulators, respectively.

Abstract: A filterless high-efficiency class D power amplifier (HEPA) exploits the phase relationships of even and odd harmonics at transistor drains of a push-pull topology to eliminate output filtering, enabling an ultra-high-efficiency, low harmonic signal. The filterless HEPA relieves the amplifier of a requirement for a power consuming filter by implementing a high-quality operational harmonic block on an output stage without output buffering. The operational harmonic block senses the voltage source radio frequency to the amplifier prior to waveform squaring and employs a harmonic canceling balun to block even harmonics (in-phase) but pass odd harmonics (180° out of phase). The sensed ideal voltage source shunts the odd-harmonic currents to ground, leaving only the fundamental current on its primary to pass to the load.

Abstract: An antenna matching system includes an electronically tunable antenna matching circuit, a first directional coupler, a first gain and phase detector, a second directional coupler, a second gain and phase detector, and a controller. The first directional coupler is configured to receive forward and reflected signals. The first gain and phase detector is configured to output a first magnitude measurement and a first phase measurement based on the signals received at the first directional coupler. The second directional coupler is also configured to receive the forward and reflected signals. The second gain and phase detector is configured to output a second magnitude measurement based on the signals received at the second directional coupler. The controller is configured to: determine circuit parameters based on the first magnitude and phase measurements; tune the matching circuit based on the circuit parameters; and check for phase error based on the second magnitude measurement.

Abstract: A high efficiency outphasing power amplifier is disclosed which provides a high-efficiency, high-linearity outphasing amplifier capable of amplifying complex, wideband, multi-tone signals. Systems herein may amplify at least 256 symbol QAM signals with negligible distortion, while achieving high direct current-to-radio frequency efficiency sustainable at virtually all power levels. Embodiments of the outphasing amplifier employ a bridge output network formed from two complementary Class-D amplifiers to switch a dc supply voltage across the load. In embodiments, the phase of both halves of the bridge is varied from zero to +/?90 or zero to 180 degrees to split the workload, to correct for phase error within the bridge network and to control output power. Because the current through the load and thus through the two halves of the amplifier vary directly with output level, the efficiency remains high even when power output is low.

Abstract: A magnitude of radio frequency voltage and current, input into a load from a radio frequency power source, are measured at a single point along a transmission line. Phase difference between voltage and current is also measured. These measurements are used to compute VSWR and forward input power. The computed measurements may be compared against predetermined VSWR limits, and operation of the radio frequency power source can be adjusted to prevent damage to the detection apparatus or load.

Abstract: A bipolar modulator and its associated control devices for use with a high-efficiency amplifier in an RF transmitter. The modulator receives an inverted reference signal that has passed through at least two comparators. The modulator output is filtered and then rectified and coupled to a high-efficiency power amplifier.

Abstract: A wideband high efficiency amplification system for amplifying radio frequency signals to high power levels. The system includes components adapted for generating an RF carrier signal having a multi-level waveform which may be characterized as a "modified square wave" including one or more intermediate voltage levels. This RF carrier waveform allows the power of the signal to be amplified with high efficiency beyond the efficiency levels which can ordinarily be achieved with conventional wideband class D amplifiers. The preferred embodiment of the invention describes an amplification system generating and using a three level waveform although waveforms having more than three levels may also be used.