Abstract: Disclosed is an amplification circuit, which includes a first amplifier that receives an external signal and performs first band pass filtering on the external signal to output a first filter signal, and a second amplifier that receives the first filter signal and performs second band pass filtering on the first filter signal to output a second filter signal, and a frequency pass bandwidth of the second band pass filtering is narrower than a frequency pass bandwidth of the first band pass filtering.

Abstract: A hybrid communication device, an operation method thereof, and a communication system including the same are provided. The hybrid communication device includes a contact unit that includes an antenna for receiving a first communication signal and an electrode for receiving a second signal, a switch controller that includes a first switch and a second switch and controls the first switch and the second switch based on a change in capacitance of the electrode, and a signal processing unit that receives at least one of the first communication signal and the second communication signal from the contact unit via the first switch and processes the received signal. The first switch is connected to the contact unit, and the signal processing unit is connected to the first switch.

Abstract: The present invention relates to a high frequency transformer for a differential amplifier. An exemplary embodiment of the present invention provides a high frequency transformer for a differential amplifier, including: a first metal line that is integrated and formed in an IC chip through a CMOS process and that is connected to a differential signal line of a transistor included in the IC chip; and a second metal line that is formed in an MEMS chip through an MEMS process and that is inductively coupled with the first metal line in a state spaced apart from an upper portion of the first metal line, wherein the MEMS chip may be stacked on an upper portion of the IC chip.

Abstract: The present invention relates to a high frequency transformer for a differential amplifier. An exemplary embodiment of the present invention provides a high frequency transformer for a differential amplifier, including: a first metal line that is integrated and formed in an IC chip through a CMOS process and that is connected to a differential signal line of a transistor included in the IC chip; and a second metal line that is formed in an MEMS chip through an MEMS process and that is inductively coupled with the first metal line in a state spaced apart from an upper portion of the first metal line, wherein the MEMS chip may be stacked on an upper portion of the IC chip.

Abstract: The present invention related to a varactor used in an integrated circuit of a differential structure. An exemplary embodiment of the present invention provides a variable capacitor connected between first and second signal lines which are differential signal lines included in an integrated circuit of a differential structure, including: a plurality of N-type semiconductors separately arranged; one or more P-type semiconductors disposed between the N-type semiconductors to make first and second PN junctions with N-type semiconductors contacting upper and lower portions thereof and to receive a control voltage, wherein, among the N-type semiconductors, first N-type semiconductors corresponding to (2n?1)-th (n being a positive integer) are connected with the first signal line, and second N-type semiconductors corresponding to 2n-th are connected with the second signal line, and parasitic capacitances of the first and second PN junctions are varied by adjusting the control voltage.

Abstract: An oscillator with a differential structure which is formed in an integrated circuit, including: a first transistor and a second transistor in each of which a drain electrode, a gate electrode, and a source electrode are sequentially arranged, a drain of the first transistor is connected with a gate of the second transistor through a first wiring, a drain of the second transistor is connected with a gate of the first transistor through a second wiring, and a first end of a source of the first transistor and a first end of a source of the second transistor are connected through a third wiring, and a second end of the source of the first transistor and a second end of the source of the second transistor are connected through a fourth wiring.

Abstract: Disclosed is a device for chip-to-chip wireless power transmission. The device includes: a first transistor that outputs a first output signal; a second transistor that outputs a second output signal having a phase opposite to that of the first output signal; capacitors that each have a first terminal and a second terminal connected the first transistor and the second transistor, respectively; and a transmitting coil that wirelessly transmits AC power outputted through the first and second transistors to a receiving coil of a power receiver.

Abstract: An oscillator with a differential structure which is formed in an integrated circuit, including: a first transistor and a second transistor in each of which a drain electrode, a gate electrode, and a source electrode are sequentially arranged, a drain of the first transistor is connected with a gate of the second transistor through a first wiring, a drain of the second transistor is connected with a gate of the first transistor through a second wiring, and a first end of a source of the first transistor and a first end of a source of the second transistor are connected through a third wiring, and a second end of the source of the first transistor and a second end of the source of the second transistor are connected through a fourth wiring.

Abstract: Disclosed is a voltage controlled oscillator which includes a first transistor in which a first terminal is connected to a first power supply, a body is connected to a gate, and a first output signal is output through a second terminal; a second transistor that is cross-coupled to the first transistor in such a manner that a first terminal is connected to the first power supply, a body connected to the second terminal of the first transistor is connected to a gate, and a second terminal is connected to the body of the first transistor, and that outputs a second output signal having an opposite phase to that of the first output signal through the second terminal; and a resonance filter in which a first terminal is connected to the second terminal of the first transistor and a second terminal is connected to the second terminal of the second transistor.