A linearization circuit that reduces intermodulation distortion in an amplifier output receives a first signal that includes a first frequency and a second frequency and generates a difference signal having a frequency approximately equal to the difference of the first frequency and the second frequency. The linearization circuit generates an envelope signal based at least in part on a power level of the first signal and adjusts a magnitude of the difference signal based on the envelope signal. When the amplifier receives the first signal at an input terminal and the adjusted signal at a second terminal, intermodulation between the adjusted signal and the first signal cancels at least a portion of the intermodulation products that result from the intermodulation of the first frequency and the second frequency.

An electronic device is provided. The electronic device includes a housing including a first surface, a second surface disposed facing an opposite side of the first surface, and a side surface configured to surround at least a portion of a space between the first surface and the second surface, a first elongated metal member configured to form a first portion of the side surface and including a first end and a second end, at least one communication circuit electrically connected to a first point of the first elongated metal member through a capacitive element, at least one ground member disposed in an interior of the housing, and a first conductive member configured to electrically connect a second point of the first elongated metal member to the ground member. The second point of the first elongated metal member is disposed closer to the second end than to the first point.

Disclosed are systems and methods related to reducing intermodulation products in an RF output signal by matching an impedance of the power amplifier to an impedance of the antenna and concurrently blocking signals having a second fundamental frequency received by the antenna when the antenna is transmitting to inhibit intermodulation products of the first and second fundamental frequencies from re-radiating from the antenna. The matching and blocking are performed concurrently by a single circuit with combined matching and blocking functionality.

A radio frequency switch circuit with improved harmonic suppression and low insertion loss has an antenna port and a plurality of signal ports. A plurality of transistor switch circuits, are connected to a respective one of the plurality of signal ports and to the antenna port. Each of the transistor switch circuits has a transistor, which in an off state, together with a harmonic suppression capacitor and a parallel inductor both connected thereto, define a tank circuit that suppresses RF signals applied to the corresponding transistor switch circuit from a different one of the transistor switch circuits. The harmonic suppression capacitor is tuned to distribute large signal voltage swings in the RF signal amongst parasitic diodes of the transistor.

A radio frequency (RF) front-end apparatus is provided. In examples discussed herein, the RF front-end apparatus can be configured to communicate RF signals in millimeter wave (mmWave) RF frequencies (e.g., 12 GHz). The RF front-end apparatus includes an RF front-end circuit and an antenna element. The RF front-end circuit includes a transmit path and a receive path for transmitting and receiving RF signals, respectively. The antenna element includes an input port(s) and an output port(s) that are coupled to the transmit path and the receive path, respectively. The antenna element can be configured to enable impedance matching between the input port(s) and the transmit path, as well as between the output port(s) and the receive path. As a result, it may be possible to reduce insertion losses in the RF front-end circuit, thus helping to improve performance of the RF front-end apparatus, particularly in support of mmWave communications.

An electronic device is provided. The electronic device includes a housing including a first surface, a second surface disposed facing an opposite side of the first surface, and a side surface configured to surround at least a portion of a space between the first surface and the second surface, a first elongated metal member configured to form a first portion of the side surface and including a first end and a second end, at least one communication circuit electrically connected to a first point of the first elongated metal member through a capacitive element, at least one ground member disposed in an interior of the housing, and a first conductive member configured to electrically connect a second point of the first elongated metal member to the ground member. The second point of the first elongated metal member is disposed closer to the second end than to the first point.

An apparatus includes a low-noise amplifier having an input and an output, a first switch coupled between the input of the low-noise amplifier and the output of the low-noise amplifier, and a transformer including a first inductor and a second inductor, wherein the first inductor is coupled to the output of the low-noise amplifier. The apparatus also includes a power amplifier having an input and an output, and a switching circuit coupled between the output of the power amplifier and the second inductor.

First and second frequency bands used for multiband communication are both higher than or equal to about 3 GHz, and do not overlap each other. The spacing between the first and second frequency bands is less than or equal to about 10% of the lower one of the lower-bound frequency of the first frequency band and the lower-bound frequency of the second frequency band. A radio-frequency circuit includes a first antenna, a second antenna, a first multiplexer connected to the first antenna, and a second multiplexer connected to the second antenna. The first multiplexer includes a first filter with a pass band including the first frequency band, and a third filter with a pass band different from the first filter. The second multiplexer includes a second filter with a pass band including the second frequency band, and a fourth filter with a pass band that differs from the second filter.

A signal switch includes a first transistor coupled between first and second nodes, a plurality of second transistors coupled in series between the first and second nodes and in parallel with the first transistor, and a first shunt path including a first shunt transistor and a first inductor connected in series between a reference node and a first connection point between two of the plurality of second transistors.

Communications systems containing an electrically-isolated Push-To-Talk (EI-PTT) device are described in this application. The communication systems contain multiple radios, a microphone/headset, and a centralized power supply. The systems also contain an EI-PTT device which reduces or eliminates noise that can disrupt the audio transmission. The EI-PTT device allows an operator or user of the communication system to actuate a button which remotely switches the radio from receive mode to transmit mode. This allows multiple users to listen (receive) to communication traffic on the same frequency at all times, but only speak (transmit) on the frequency while activating the EI-PTT device. Unlike other PTT devices which electrically tie the ground signals inside the device, the EI-PTT devices electrically isolate the ground signals to reduce the problem of noise coupling. Other embodiments are described.