Abstract: Provided is a differential cascode voltage-controlled oscillator that can reduce a phase noise by the use of a quality factor enhancement technique with negative conductance and can mitigate a ground-caused noise effect by the use of a cascode connection technique. The differential cascode voltage-controlled oscillator includes an AC signal generator, and first through fourth cascode amplifiers. The AC signal generator generates an AC signal with a certain frequency according to a control voltage. The first cascode amplifier is connected in a cascode configuration, and amplifies the AC signal to output the resulting signal to a first output terminal. The second cascode amplifier is connected in a cascode configuration and connected to the first cascode amplifier in a cross-coupled configuration, to amplify the AC signal to output the resulting signal to a second output terminal.

Abstract: The present invention relates to a signal converting device and receiving device in a wireless communication system. The receiving device of the wireless communication system includes a differential signal converter for receiving a single ended radio frequency signal and converting it into a differential radio frequency signal, and a frequency down converter for down converting the differential radio frequency signal to down frequency signal.

Abstract: The present invention relates to a leakage signal reducing device and method. The present invention uses a signal with varied phase and gain output by a local oscillator to eliminate a leakage signal leaked by a local oscillator to a frequency converter.

Abstract: Provided are an apparatus for adjusting frequency characteristic and Q factor of a low pass filter (LPF) and a method thereof. The apparatus includes: a frequency comparing unit for calculating a first square value and a second square value, and comparing a first reference value with the first and the second square values; a frequency adjusting unit for adjusting the frequency characteristic to range the first reference value between the first square value and the second square value; a Q factor comparing unit for calculating a third square value, and comparing a second and a third reference values with the third square value; a control unit for activating the Q factor comparing unit when the frequency characteristic is completely adjusted; and a Q factor adjusting unit for adjusting the Q factor to range the third square value between the second reference value and the third reference value.

Abstract: Provided is a differential cascode voltage-controlled oscillator that can reduce a phase noise by the use of a quality factor enhancement technique with negative conductance and can mitigate a ground-caused noise effect by the use of a cascode connection technique. The differential cascode voltage-controlled oscillator includes an AC signal generator, and first through fourth cascode amplifiers. The AC signal generator generates an AC signal with a certain frequency according to a control voltage. The first cascode amplifier is connected in a cascode configuration, and amplifies the AC signal to output the resulting signal to a first output terminal. The second cascode amplifier is connected in a cascode configuration and connected to the first cascode amplifier in a cross-coupled configuration, to amplify the AC signal to output the resulting signal to a second output terminal.

Abstract: Provided are an apparatus for adjusting frequency characteristic and Q factor of a low pass filter (LPF) and a method thereof. The apparatus includes: a frequency comparing unit for calculating a first square value and a second square value, and comparing a first reference value with the first and the second square values; a frequency adjusting unit for adjusting the frequency characteristic to range the first reference value between the first square value and the second square value; a Q factor comparing unit for calculating a third square value, and comparing a second and a third reference values with the third square value; a control unit for activating the Q factor comparing unit when the frequency characteristic is completely adjusted; and a Q factor adjusting unit for adjusting the Q factor to range the third square value between the second reference value and the third reference value.

Abstract: Disclosed is an apparatus and method for generating pulse based on time delay and wave transform and transmitter of multi-frequency band communication system using the same. The apparatus includes: an apparatus for generating a pulse based on time delay and wave transform, including: a time delay control unit having a plurality of time delay controller, each for providing time delay information; an amplitude control unit for providing amplitude information; a time delay unit having a plurality of time delayers, each for departing a square wave from a trigger signal, delaying time of the square wave based on the time delay information, and adjusting an amplitude of the square wave based on the amplitude information, to thereby generate a time-delayed signal; a pulse shaping unit for shaping a pulse based on the time-delayed signals; and a wave transforming unit for transforming the pulse to a desired signal.

Abstract: A micro-miniature, light weighted and low cost trapezoid ultra wide antenna having an ultra wide band characteristics and a notch characteristic in 5 GHz WLAN band (5.15–5.35 GHz) is disclosed. The trapezoid ultra wide antenna includes: a dielectric substrate; a trapezoid shaped patch formed at an upper end of a middle line on an upper side of the dielectric substrate; a feeding line formed at a bottom end of the middle line on the upper side of the dielectric substrate for feeding electric power to the trapezoid shaped patch; a matching stub formed between the trapezoid shaped patch and the feeding line for impedance matching between the trapezoid shaped patch and the feeding line; and a ground formed at a side of the feeding line on the upper side of the dielectric substrate.

Abstract: A micro-miniature, light weighted and low cost trapezoid ultra wide antenna having an ultra wide band characteristics and a notch characteristic in 5 GHz WLAN band (5.15-5.35 GHz) is disclosed. The trapezoid ultra wide antenna includes: a dielectric substrate; a trapezoid shaped patch formed at an upper end of a middle line on an upper side of the dielectric substrate; a feeding line formed at a bottom end of the middle line on the upper side of the dielectric substrate for feeding electric power to the trapezoid shaped patch; a matching stub formed between the trapezoid shaped patch and the feeding line for impedance matching between the trapezoid shaped patch and the feeding line; and a ground formed at a side of the feeding line on the upper side of the dielectric substrate.

Abstract: Disclosed is an apparatus and method for generating pulse based on time delay and wave transform and transmitter of multi-frequency band communication system using the same. The apparatus includes: an apparatus for generating a pulse based on time delay and wave transform, including: a time delay control unit having a plurality of time delay controller, each for providing time delay information; an amplitude control unit for providing amplitude information; a time delay unit having a plurality of time delayers, each for departing a square wave from a trigger signal, delaying time of the square wave based on the time delay information, and adjusting an amplitude of the square wave based on the amplitude information, to thereby generate a time-delayed signal; a pulse shaping unit for shaping a pulse based on the time-delayed signals; and a wave transforming unit for transforming the pulse to a desired signal.