Abstract: A wireless communication module includes a plurality of monolithic millimeter-wave integrated circuits (MMICs) for signal processing attached to the top surface of a multi-layer low temperature co-fired ceramic substrate; a planar transmission line formed on the top surface of the multi-layer substrate for communications between the MMICs; a metal base attached to the bottom surface of the multi-layer substrate and having an opening to which an antenna is attached; a plurality of vias for connecting the metal base and the planar transmission line within the multi-layer substrate to establish a uniform potential on a ground plane of the multi-layer substrate; an embedded waveguide formed in the opening surrounded with the vias within the multi-layer substrate; and a planar transmission line-to-waveguide transition apparatus for the transition of waves between the planar transmission line and the embedded waveguide.

Abstract: Disclosed are a beamformer and a beamforming method. The beamformer includes a plurality of dividers, each of which divides an input signal along a plurality of paths, an input switch which selects one of the dividers such that the input signal is input to the selected divider, a phase shifter which shifts phases of respective output signals from the divider, and an output switch which transmits the output signals from the phase shifter to an antenna.

Abstract: A resistive frequency mixing apparatus includes a first frequency mixer having a source follower FET, and a second frequency mixer having a common source FET. The resistive frequency mixing apparatus perform a frequency mixing of an RF depending on an LO signal to generate a down-converted IF signal when the RF signal is applied to the source follower FET and the LO signal is applied to the common source FET. Further, the resistive frequency mixing apparatus performs a frequency mixing of an IF signal depending on an LO signal through the use of the source follower FET to produce an up-converted RF signal when the IF signal is applied to the common source FET and the LO signal is applied to the common source FET.

Abstract: Provided is a direct-conversion frequency mixer for down converting a radio frequency (RF) signal into a baseband signal, in which a single phase RF signal and a quadrature location oscillation (quadrature LO) signal are used to generate the baseband signal, the frequency mixer comprising a first frequency mixing unit that uses quadrature LO signals having respective phases of 0 degrees and 180 degrees to directly down-convert the single phase RF signal into the in-phase baseband signal, and a second frequency mixing unit that uses quadrature LO signals having respective phases of 90 degrees and 270 degrees to directly down-convert the single phase RF signal into the quadrature-phase baseband signal, whereby drains and sources of the transistor for receiving the quadrature LO signal and the transistor for receiving the RF signal are connected in common, thus enabling low power source voltage driving.

Abstract: There is provided a power amplifying device having a linearizer in which a bias circuit has an initial impedance set when initially operated, then the impedance is varied according to a level of an input signal and the input signal is amplified in a broad range from a low level region to a high level region, thereby improving linearity of an output signal. The power amplifying device including: an amplifying unit receiving a bias power source and amplifying an input signal; a bias unit varying the bias power source according to a set impedance to provide to the amplifying unit; and an impedance setting unit setting the impedance of the bias unit in response to a preset control voltage when the bias unit is initially operated and re-setting the impedance of the bias unit according to a level of the input signal of the amplifying unit after initial operation of the bias unit.

Abstract: A circuit for improving amplification and noise characteristics of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), and a frequency mixer, an amplifier and an oscillator using the circuit are provided. A gate terminal of the MOSFET is connected to a body terminal of the MOSFET through a capacitor and the gate and body terminals of the MOSFET are connected to a current source to simultaneously provide a signal to both the gate terminal and the body terminal, in order to improve amplification and noise characteristics of the MOSFET. As a result, a higher level of amplification and a lower level of noise than the conventional art can be obtained.

Abstract: A circuit for improving amplification and noise characteristics of a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), and a frequency mixer, an amplifier and an oscillator using the circuit are provided. A gate terminal of the MOSFET is connected to a body terminal of the MOSFET through a capacitor and the gate and body terminals of the MOSFET are connected to a current source to simultaneously provide a signal to both the gate terminal and the body terminal, in order to improve amplification and noise characteristics of the MOSFET. As a result, a higher level of amplification and a lower level of noise than the conventional art can be obtained.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor, a bias circuit including a bias transistor, the bias circuit providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to fluctuation in a reference voltage and variation in temperature, for adjusting the bias current to control an operation current of the amplifying transistor.

Abstract: A transimpedance amplification apparatus includes a signal source for generating a current signal, a source follower stage, a common source stage and a shunt feedback resistor. The source follower stage having a source follower structure receives the current signal to reduce an impedance of the signal source. The common source stage, following the source follower stage, driven by the reduced signal source impedance, amplifies the current signal to extend a frequency bandwidth of the current signal and buffers the amplified signal with the extended frequency bandwidth thereof maintained, wherein the reduced signal source impedance serves to extend a frequency bandwidth of the common source stage. The shunt feedback resistor, which is installed between the source follower stage and the common source stage, adjusts an input DC bias of the source follower stage and increasing a transimpedance gain of the common source stage.

Abstract: In a wideband variable frequency voltage controlled oscillator, an LC resonance circuit determines an oscillation frequency based on an externally inputted voltage signal. A negative resistance generating circuit generates a signal having the oscillation frequency determined by the LC resonance circuit. A buffer circuit transfers the oscillation frequency generated by the negative resistance generating circuit to a load. A variable capacitor connecting circuit connects the negative resistance generating circuit and the buffer circuit to transfer the signal having the oscillation frequency from the negative resistance generating circuit to the buffer circuit.

Abstract: An adaptive bias circuit is provided for an amplifier module including a RF power amplifier for amplifying an input signal to generate an output signal, wherein the bias circuit receives the input signal to adjust a driving current to control a quiescent current of the RF power amplifier. The adaptive bias circuit includes means for providing the driving current to the bias circuit and means for drawing a bypass current from the providing means to reduce the driving current in response to the input signal, wherein the quiescent current is reduced when the driving current is reduced and the bypass current increases when the input signal is reduced.

Abstract: A broadband amplification apparatus for extending a bandwidth includes a first and a second amplifying unit for amplifying an input signal, a buffering unit and a first inductive buffer. The buffering unit disposed between the first and the second amplifying unit buffers an output signal of the first amplifying unit to thereby maintain a bandwidth of the output signal, increases a gain and returns back a portion of the buffered signal to the first amplifying unit. The first inductive buffer, which is connected to the buffer unit, enhances input impedance as a frequency increases within a predetermined range, thereby introducing little gain changes while serving to extend a bandwidth.

Abstract: An adaptive bias circuit is provided for an amplifier module including a RF power amplifier for amplifying an input signal to generate an output signal, wherein the bias circuit receives the input signal to adjust a driving current to control a quiescent current of the RF power amplifier. The adaptive bias circuit includes means for providing the driving current to the bias circuit and means for drawing a bypass current from the providing means to reduce the driving current in response to the input signal, wherein the quiescent current is reduced when the driving current is reduced and the bypass current increases when the input signal is reduced.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor for generating an output of the mobile handset, a bias circuit having a bias transistor and providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to a control signal, for adjusting the bias current to control an operation current of the amplifying transistor. The control signal is generated by the mobile handset, and the control signal is determined by a power level of the output of the mobile handset.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor, a bias circuit including a bias transistor, the bias circuit providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to fluctuation in a reference voltage and variation in temperature, for adjusting the bias current to control an operation current of the amplifying transistor.

Abstract: A transimpedance amplification apparatus includes a signal source for generating a current signal, a source follower stage, a common source stage and a shunt feedback resistor. The source follower stage having a source follower structure receives the current signal to reduce an impedance of the signal source. The common source stage, following the source follower stage, driven by the reduced signal source impedance, amplifies the current signal to extend a frequency bandwidth of the current signal and buffers the amplified signal with the extended frequency bandwidth thereof maintained, wherein the reduced signal source impedance serves to extend a frequency bandwidth of the common source stage. The shunt feedback resistor, which is installed between the source follower stage and the common source stage, adjusts an input DC bias of the source follower stage and increasing a transimpedance gain of the common source stage.

Abstract: A bias control circuit for a power amplifier including an RF amplifier having a transistor for power amplification, comprises two components. A first component is a bias circuit having an active bias transistor operating in an active mode and connected to a predetermined Vref pin to provide the transistor for power amplification with a base current and a second component is a bias current control circuit having another active bias transistor connected to a predetermined Vcon pin and turned on or off depending on a high or a low mode of the Vcon pin to thereby control a base current and a quiescent current of the transistor for power amplification.

Abstract: In a multilayer RF module, a plurality of vertically stacked ceramic layers include a first to a third ceramic layers. Each of the first and the third ceramic layers has a circuit component thereon and the second ceramic layer is located between the first and the third ceramic layers and is provided with at least one or more air cavities filled with air, the air cavities being vertically aligned with the circuit components of the first and the third ceramic layers.

Abstract: A broadband amplification apparatus for extending a bandwidth includes a first and a second amplifying unit for amplifying an input signal, a buffering unit and a first inductive buffer. The buffering unit disposed between the first and the second amplifying unit buffers an output signal of the first amplifying unit to thereby maintain a bandwidth of the output signal, increases a gain and returns back a portion of the buffered signal to the first amplifying unit. The first inductive buffer, which is connected to the buffer unit, enhances input impedance as a frequency increases within a predetermined range, thereby introducing little gain changes while serving to extend a bandwidth.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor for generating an output of the mobile handset, a bias circuit having a bias transistor and providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to a control signal, for adjusting the bias current to control an operation current of the amplifying transistor. The control signal is generated by the mobile handset, and the control signal is determined by a power level of the output of the mobile handset.