In many examples, a device comprises a transmitter. The transmitter comprises a power amplifier, a first transformer coil coupled to the power amplifier, and a second transformer coil adapted to be electromagnetically coupled to the first transformer coil. The transmitter also comprises a first bond wire coupled to a first end of the second transformer coil and adapted to be coupled to a first end of an antenna, a capacitor coupled to a second end of the second transformer coil, a switch coupled to the capacitor and configured to engage and disengage the capacitor from the transmitter, and a second bond wire coupled to the switch and adapted to be coupled to a second end of the antenna.

A radio frequency circuit includes a power amplifier configured to selectively amplify one of a first radio frequency signal and a second radio frequency signal that have different bandwidths, and when the first radio frequency signal is input to the power amplifier, a first bias signal is applied to the power amplifier, and when the second radio frequency signal is input to the power amplifier, a second bias signal different from the first bias signal is applied to the power amplifier.

Apparatus and methods for power amplifier output matching is disclosed. In one aspect, there is provided an output matching circuit including an input configured to receive an amplified radio frequency signal from a power amplifier, a first output, and a second output. The output matching circuit further includes a first matching circuit electrically connected between the input of the output matching circuit and the first output, the first matching circuit configured to suppress harmonics of a fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a first band. The output matching circuit further includes a second matching circuit electrically connected between the input of the output matching circuit and the second output, the second matching circuit configured to suppress harmonics of the fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a second band different from the first band.

Provided is a high frequency communication apparatus and method for vehicle. The high frequency communication apparatus for vehicle includes a communication module configured to process a radio frequency (RF) signal; a cable having one end connected to the communication module; and an antenna module connected to the other end of the cable and configured to transmit through an antenna the RF signal delivered from the communication module, the antenna module including a compensator configured to compensate for a loss of the RF signal in the cable and a controller configured to determine an amount of compensation for the loss in the cable based on power of the RF signal transmitted from the compensator.

A switch device includes a first node, a switch unit, an adjustment switch, an impedance element, a second node and a detection unit. A first terminal of the switch unit is coupled to the first node. A first terminal and a second terminal of the adjustment switch are respectively coupled to a second terminal of the switch unit and a reference voltage terminal. A first terminal and a second terminal of the impedance element are respectively coupled to the first terminal and the second terminal of the adjustment switch. The detection unit is coupled to the second node, and a control terminal of the switch unit and a control terminal of the adjustment switch. The detection unit detects a node signal at the second node to accordingly control the switch unit and the adjustment switch.

A radio frequency circuit includes a transmit power amplifier, a differential transmit signal path having first and second paths, and first and second baluns. The first balun can be configured to convert a single ended transmit signal into a differential transmit signal, and the second balun can be configured to convert the differential transmit signal back to a single ended transmit signal. The circuit can also include a pair of transmit filters between the first and second baluns and including a first transmit filter connected in the first path and a second transmit filter connected in the second path. The second balun cancels harmonic noise generated by the pair of transmit filters.

A circuit device includes a directional coupler with a first port receiving a radiofrequency signal, a second port outputting a signal in response to signal received by the first port, and a third port outputting a signal in response to a reflection of the signal at the second port. An impedance matching network is connected between the second port and an antenna. The impedance matching network includes fixed inductive and capacitive components and a single variable inductive or capacitive component. A diode coupled to the third port of the coupler generates a voltage at a measurement terminal which is processed in order to select and set the inductance or capacitance value of the variable inductive or capacitive component.

This application provides a downlink transmitting system and a switching method. The downlink transmitting system includes at least one digital intermediate frequency module group, at least one Tx port group, a plurality of PAs, at least one switching switch, and an antenna array. The plurality of PAs are connected to the antenna array. The plurality of PAs are connected to all Tx ports included in the downlink transmitting system in a one-to-one correspondence. The at least one digital intermediate frequency module group is in a one-to-one correspondence with the at least one Tx port group. Each Tx port group is connected to each digital intermediate frequency module in a corresponding digital intermediate frequency module group through one switching switch. Each Tx port group includes a plurality of Tx ports.

A method improves antenna matching for a wireless node, preferably of a sensor wireless node and/or actuator wireless node. A radio signal, or at least a portion thereof, is coupled out of the antenna and/or out of the transmit path of the wireless node. The impedance and/or the resonant frequency of the antenna is determined therefrom in the wireless node, and the impedance and/or the resonant frequency of the antenna is adjusted according to the determined impedance and/or resonant frequency by a circuit acting on the antenna.

The antenna module includes a first substrate and a second substrate on each of which a radiating element is arranged, a third substrate, and a switch circuit. An RFIC for supplying a radio frequency signal to the first substrate and the second substrate is arranged on the third substrate. The switch circuit is configured to change over a connection between the RFIC and the radiating element on the first substrate and a connection between the RFIC and the radiating element on the second substrate.