Envelope tracking can be employed to reduce power consumption of a power amplifier, but envelope tracking can introduce nonlinearities to a power amplifier. These nonlinearities can manifest themselves as noise at the output of the power amplifier. Embodiments described herein provide techniques for characterizing a parameter indicative of power amplifier noise when envelope tracking is employed. Measurement of this parameter can permit power amplifier designers to decide whether to forgo envelope tracking if a power amplifier is too susceptible to such noise, redesign the power amplifier to improve compatibility with envelope tracking, or to employ distortion compensation circuitry to reduce the noise output by the power amplifier. Counterintuitively, this distortion compensation circuitry may involve increasing the power, such as the envelope tracking power supply. However, increasing the power may be a desirable trade-off for increased linearity.

In accordance with the concepts, systems, methods and techniques described herein a tripole current loop radiating element is provided having three conductors disposed on a substrate with the three conductors being physically spaced apart from each other and arranged to be responsive to radio frequency (RF) signals at a desired frequency range. Each of the three conductors includes a ground via to couple the respective conductor to a ground plane and a signal via to receive RF signals from a single feed circuit. The feed circuit includes a signal port, and first, second and third antenna ports, with each of the antenna ports coupled to a respective one of the three conductors. The feed circuit can provide the RF signals to each of the three conductors having equal amplitudes and distributed with relative phases of 0/120/240 respectively (i.e., phase shifted by 120 from an adjacent conductor).

A cable type antenna is provided having a small-sized lightweight configuration and enabling specifying of a radiation region having a desired antenna length. The cable type antenna may be sectionalized into a first region on the power feeding circuit side and a second region on the leading end side. The cable type antenna of the present disclosure further comprises a balanced-to-unbalanced transformer element disposed between the first region and the second region, wherein the balanced-to-unbalanced transformer element includes an unbalanced-side terminal connected to the first region and a balanced-side terminal connected to the second region configured to allow the first region to serve as a non-radiation part and the second region to serve as a radiation part.

A cable type antenna is provided having a small-sized lightweight configuration and enabling specifying of a radiation region having a desired antenna length. The cable type antenna may be sectionalized into a first region on the power feeding circuit side and a second region on the leading end side. The cable type antenna of the present disclosure further comprises a balanced-to-unbalanced transformer element disposed between the first region and the second region, wherein the balanced-to-unbalanced transformer element includes an unbalanced-side terminal connected to the first region and a balanced-side terminal connected to the second region configured to allow the first region to serve as a non-radiation part and the second region to serve as a radiation part.

A power amplifier (PA) system is provided for multi-mode multi-band operations. The PA system includes one or more amplifying modules, each amplifying module including one or more banks, each bank comprising one or more transistors; and a plurality of matching modules, each matching module being configured to be adjusted to provide impedances corresponding to frequency bands and conditions. A controller dynamically controls an input terminal of each bank and adjusts the matching modules to provide a signal path to meet specifications on properties associated with signals during each time interval.

Adaptive self-tunable antenna systems and methods are provided including a closed-loop system for sensing near-field RF signals of transmitted RF signals and tuning an antenna or switching between multiple antennas, so that the strength of the transmitted RF signals is maximized. A sensing antenna detects the near-field RF signal, which is filtered and converted to an RF strength control signal that can be used to generate an antenna tuning control signal. An antenna tuner uses the antenna tuning control signal to keep the antenna in resonance by dynamically changing the electrical length of the antenna or switching between multiple antennas to maximize the strength of the radiated RF signal. Such antennas may be less prone to detuning due to interaction with human bodies or other objects. Dynamically matching the antennas to an RF power amplifier and low noise amplifier can improve stability, power efficiency, gain, noise figure, and receiver sensitivity.

An antenna device is provided that can be designed easily and includes a flat antenna of which communication characteristics do not change significantly even when there exist metallic objects or the like in the surroundings. Moreover, the flat antenna is provided with an antenna-side signal line path conductor, an antenna-side first ground conductor, a matching circuit part, and an antenna-side connector part which are provided in an antenna-side insulator. The antenna device further includes a signal transmission cable that is provided with a radiation area setting part in the vicinity of a cable-side connector part. The antenna device is designed such that, by connecting the antenna-side connector part and the cable-side connector part to each other, substantially the entire surface of the flat antenna serves as a radiation part that radiates electromagnetic waves.

An antenna device is provided that can be designed easily and includes a flat antenna of which communication characteristics do not change significantly even when there exist metallic objects or the like in the surroundings. Moreover, the flat antenna is provided with an antenna-side signal line path conductor, an antenna-side first ground conductor, a matching circuit part, and an antenna-side connector part which are provided in an antenna-side insulator. The antenna device further includes a signal transmission cable that is provided with a radiation area setting part in the vicinity of a cable-side connector part. The antenna device is designed such that, by connecting the antenna-side connector part and the cable-side connector part to each other, substantially the entire surface of the flat antenna serves as a radiation part that radiates electromagnetic waves.

Communication between a wireless base-station and a microwave reflector link are enhanced by feeding back a portion of the transmitter signal, adjusted for phase and amplitude, to cancel ambient reflection blocker signals being received at the base-station. The microwave reflector link does not utilize a transmitter gain stage, but communicates data back to the base-station in response to modulating the reflections of its antenna (e.g., in gain and/or phase). The disclosure aids in the proper amplification and processing of reflection signals from the microwave reflector link, by canceling out the blocking signals which arise as background objects reflect transmitter signal energy back to the base-station.

Communication between a wireless base-station and a microwave reflector link are enhanced by feeding back a portion of the transmitter signal, adjusted for phase and amplitude, to cancel ambient reflection blocker signals being received at the base-station. The microwave reflector link does not utilize a transmitter gain stage, but communicates data back to the base-station in response to modulating the reflections of its antenna (e.g., in gain and/or phase). The disclosure aids in the proper amplification and processing of reflection signals from the microwave reflector link, by canceling out the blocking signals which arise as background objects reflect transmitter signal energy back to the base-station.