Abstract: A microwave beam-forming antenna may include: a main reflector installed on one surface of an antenna body; an array feed horn installed on a center portion of the main reflector; a sub-reflector disposed to be spaced apart from the array feed horn on the main reflector; and a plurality of waveguide feeds respectively connected to a plurality of horn antennas arranged in the array feed horn.

Abstract: An array antenna capable of steering a beam in a first communication node of a wireless communication system may comprise: a plurality of single antennas each capable of variably adjusting a beam steering direction; a plurality of beamforming control units each of which is connected to each of the plurality of single antennas to control a beamforming operation of each of the plurality of single antennas; and an array antenna control unit connected to the plurality of beamforming control units to control a beamforming operation of the entire array antenna, wherein the plurality of single antennas are arranged in a cylindrical shape and are installed to face a direction opposite to a central direction of the cylinder shape, and the array antenna is configured to steer a beam to a predetermined area around the first communication node through at least one single antenna among the plurality of single antennas.

Abstract: An array antenna system, and a calibration method and apparatus thereof are provided. The calibration method includes measuring a signal loop including mutual coupling between antennas included in an array antenna, calculating a ratio of a reception (RX) signal received by each antenna to an RX signal received by a reference antenna of the array antenna based on a result of the measuring, and performing calibration of the array antenna based on the ratio.

Abstract: An array antenna capable of steering a beam in a first communication node of a wireless communication system may comprise: a plurality of single antennas each capable of variably adjusting a beam steering direction; a plurality of beamforming control units each of which is connected to each of the plurality of single antennas to control a beamforming operation of each of the plurality of single antennas; and an array antenna control unit connected to the plurality of beamforming control units to control a beamforming operation of the entire array antenna, wherein the plurality of single antennas are arranged in a cylindrical shape and are installed to face a direction opposite to a central direction of the cylinder shape, and the array antenna is configured to steer a beam to a predetermined area around the first communication node through at least one single antenna among the plurality of single antennas.

Abstract: A direct current-to-direct current (DC-DC) converter providing multiple operation modes includes a buck power stage configured to lower an input voltage, a boost power stage configured to increase the input voltage, and a multi-mode controller configured to control the buck power stage and the boost power stage, wherein the multi-mode controller is configured to generate a signal to control the buck power stage and the boost power stage according to the input voltage and an output voltage, and control the buck power stage and the boost power stage using the signal.

Abstract: An amplifier may comprise first and second matching networks; first and second transistors; and a transformer including first to third inductors. Also, a gate and a source of the first transistor are connected to the first matching network, one end of the first inductor is connected to a drain of the first transistor, the other end of the first inductor is connected to a source of the second transistor, one end of the second inductor is connected to a gate of the second transistor, the other end of the second inductor is grounded, one end of the third inductor is connected to a drain of the second transistor, and the other end of the third inductor is connected to the second matching network.

Abstract: An array antenna system, and a calibration method and apparatus thereof are provided. The calibration method includes measuring a signal loop including mutual coupling between antennas included in an array antenna, calculating a ratio of a reception (RX) signal received by each antenna to an RX signal received by a reference antenna of the array antenna based on a result of the measuring, and performing calibration of the array antenna based on the ratio.

Abstract: A direct current-to-direct current (DC-DC) converter providing multiple operation modes includes a buck power stage configured to lower an input voltage, a boost power stage configured to increase the input voltage, and a multi-mode controller configured to control the buck power stage and the boost power stage, wherein the multi-mode controller is configured to generate a signal to control the buck power stage and the boost power stage according to the input voltage and an output voltage, and control the buck power stage and the boost power stage using the signal.

Abstract: A communication method and apparatuses performing the same. The communication method includes arranging first subcarriers of a first frequency domain and second subcarriers of a second frequency domain based on a mirror point and performing communication based on an orthogonal frequency-division multiplexing (OFDM) communication scheme using at least one of the first subcarriers and the second subcarriers.

Abstract: Disclosed are a method and apparatus for canceling self-interference signals in a communication system. A first communication node includes a signal transmission unit configured to generate a first RF signal, an antenna module configured to transmit the first RF signal generated by the signal transmission unit and receive a second RF signal from a second communication node, a signal reception unit configured to process the second RF signal and a self-interference signal caused by the first RF signal, and an SIC circuit configured to cancel the self-interference signal. The SIC circuit includes a DSIC circuit for canceling the self-interference signal in a digital domain and an ASIC circuit and an HSIC circuit for canceling the self-interference signal in an analog domain. Accordingly, the performance of the communication system may be enhanced.

Abstract: An amplifier may comprise first and second matching networks; first and second transistors; and a transformer including first to third inductors. Also, a gate and a source of the first transistor are connected to the first matching network, one end of the first inductor is connected to a drain of the first transistor, the other end of the first inductor is connected to a source of the second transistor, one end of the second inductor is connected to a gate of the second transistor, the other end of the second inductor is grounded, one end of the third inductor is connected to a drain of the second transistor, and the other end of the third inductor is connected to the second matching network.

Abstract: A transceiving apparatus may comprise a radiator emitting a beam; a receiver receiving a beam; a first sub-reflector which is provided to face the radiator and changes an orbital angular momentum (OAM) mode order of a beam; a second sub-reflector which is provided to face the receiver and changes an OAM mode order of a beam differently from the first sub-reflector; and a main reflector which is provided to face the first sub-reflector and the second sub-reflector.

Abstract: A transmitting and receiving switch, a transmitting and receiving apparatus, and an operating method of a transmitting and receiving switch are disclosed. The transmitting and receiving switch may include a first switch configured to be connected between the transmitting front-end module and the antenna, a second switch configured to be connected between the receiving front-end module and a ground, and a first inductor configured to be connected between the second switch and the antenna, a second inductor configured to be connected between the antenna and the ground, and a variable capacitor configured to be connected between the antenna and the ground.

Abstract: Disclosed are a method for signal modulation based on pulse density modulation and an apparatus therefore. The method for signal modulation is performed in an apparatus for modulating a signal based on pulse density modulation and includes performing pulse density modulation on an analog signal input to the apparatus through a pulse density modulator of the apparatus, converting a bandwidth of the pulse density modulated signal into a bandwidth required for the apparatus through a correlative encoder of the apparatus, transmitting the bandwidth converted signal to a radio frequency (RF) unit of the apparatus based on an electrical-to-optical (E/O) converter and an optical-to-electrical (O/E) converter of the apparatus, filtering a frequency band of the bandwidth converted signal and outputting the frequency band filtered signal via the RF unit.

Abstract: Disclosed are a method and apparatus for canceling self-interference signals in a communication system. A first communication node includes a signal transmission unit configured to generate a first RF signal, an antenna module configured to transmit the first RF signal generated by the signal transmission unit and receive a second RF signal from a second communication node, a signal reception unit configured to process the second RF signal and a self-interference signal caused by the first RF signal, and an SIC circuit configured to cancel the self-interference signal. The SIC circuit includes a DSIC circuit for canceling the self-interference signal in a digital domain and an ASIC circuit and an HSIC circuit for canceling the self-interference signal in an analog domain. Accordingly, the performance of the communication system may be enhanced.

Abstract: The present disclosure relates to a wireless communication apparatus capable of increasing throughput using MIMO in an LOS environment and a method for the same. A wireless communication apparatus based on the LOS-MIMO technique may comprise a multi-link configuration unit, a frequency response correction unit, a signal compensation unit, and a feedback unit. In the apparatus, an additional LOS-MIMO equalizer is used at the front of an LOS-MIMO estimator and a coding unit in order to compensate in-band frequency characteristics of frequency response characteristics estimated by the LOS-MIMO estimator and a signal channel estimator, whereby the LOS-MIMO estimation performance can be remarkably enhanced. Also, precise separation of multiplexed signals through the above-described LOS equalizer can make it possible to increase transmission capacity by using the LOS-MIMO which can be applied to high-order mode (e.g., over 16 quadrature amplitude modulation (QAM)) digital communications.

Abstract: Disclosed are a method for signal modulation based on pulse density modulation and an apparatus therefore. The method for signal modulation is performed in an apparatus for modulating a signal based on pulse density modulation and includes performing pulse density modulation on an analog signal input to the apparatus through a pulse density modulator of the apparatus, converting a bandwidth of the pulse density modulated signal into a bandwidth required for the apparatus through a correlative encoder of the apparatus, transmitting the bandwidth converted signal to a radio frequency (RF) unit of the apparatus based on an electrical-to-optical (E/O) converter and an optical-to-electrical (O/E) converter of the apparatus, filtering a frequency band of the bandwidth converted signal and outputting the frequency band filtered signal via the RF unit.

Abstract: An apparatus for orbital angular momentum (OAM) mode combination and an antenna apparatus for multi-mode generation are provided. The apparatus for OAM mode combination includes three input ports configured to receive independent OAM mode signals, four output ports configured to output OAM mode signals with the same or different phase delays; and a circuit element configured to simultaneously combine or distribute the OAM mode signals by controlling phases of output signals output through the four output ports to be different depending on the OAM mode signals received through the input ports.

Abstract: A transceiving apparatus may comprise a radiator emitting a beam; a receiver receiving a beam; a first sub-reflector which is provided to face the radiator and changes an orbital angular momentum (OAM) mode order of a beam; a second sub-reflector which is provided to face the receiver and changes an OAM mode order of a beam differently from the first sub-reflector; and a main reflector which is provided to face the first sub-reflector and the second sub-reflector.

Abstract: Disclosed is a circular array antenna. The circular array antenna includes: an input/output unit receiving electromagnetic waves from a transmitter and distributing the received electromagnetic waves to the antenna; a primary feeder connected with the input/output unit and placed at the center of the circular array antenna; a plurality of secondary feeders radially connected to the primary feeder; a plurality of patch units connected to the respective secondary feeders to generate an electric field radially; and a plurality of length controllers formed at terminals of the respective secondary feeders in a direction to extend the lengths of the respective secondary feeders, of which the lengths are controllable.