摘要:
A quadrature voltage controlled oscillator having low phase noise and excellent output swing characteristics includes a first voltage controlled oscillator for outputting a positive in-phase output signal and a negative in-phase output signal; a second voltage controlled oscillator for outputting a positive quadrature-phase output signal and a negative quadrature-phase output signal, the second voltage controlled oscillator having a symmetrical structure with the first voltage controlled oscillator and constituting a feedback loop together with the first voltage controlled oscillator; a first constant current source for supplying constant current to the first voltage controlled oscillator in response to the output signals; and a second constant current source for supplying constant current to the second voltage controlled oscillator in response to the output signals.
摘要:
Disclosed is a dual-band voltage-controlled oscillator using bias switching and output-buffer multiplexing. The dual-band voltage-controlled oscillator includes a power supply unit for supplying a source voltage; plural voltage-controlled oscillation units for outputting different oscillation frequencies according to controls of a certain tuning voltage; plural bias units for generating driving voltages for driving the voltage-controlled oscillation units and supplying the driving voltages to the voltage-controlled oscillation units; and plural buffers for selectively outputting oscillation frequencies of the plural voltage-controlled oscillation units. The present invention implements the dual-band voltage-controlled oscillator through bias switching and output-buffer multiplexing, which brings an advantage of elimination of interference between output frequencies to enhance phase noise characteristics.
摘要:
A Ultra WideBand (UWB) substrate type dipole antenna is provided which has a stable radiation pattern. The UWB substrate type dipole antenna includes a dielectric substrate, a first radiator formed on a side of the dielectric substrate, a signal line transmitting an energy from a coaxial cable to the first radiator, and a plurality of second radiators formed at a predetermined distance from the first radiator and the signal line, and respectively having therein a plurality of slits of a predetermined configuration. Because there is no leakage of electric current to an outer part of an external conductor of the coaxial cable, even when the connection of the connector and the coaxial cable to the antenna, distortion of the radiation pattern of the antenna is prevented. As a result, the same radiation pattern and the direction of maximum radiation may be obtained before and after connection with the connector and the coaxial cable.
摘要:
A multi-band radio frequency (RF) receiving method in a mobile communication system having a reduced size and cost includes receiving RF wave signals for four or more non-overlapping bands, primarily filtering a first wide band including adjacent first and second bands and a second wide band including adjacent third and fourth bands from the received RF wave signals, low-noise amplifying the RF wave signals of the first and second wide bands, respectively, secondarily filtering a third wide band including adjacent second and third bands and a fourth wide band including first and fourth bands from the low-noise amplified RF wave signals of the first and second wide bands, generating two band RF wave signals to be simultaneously received, and frequency-down converting the two band RF wave signals generated in the secondary filtering step into two band intermediate frequency wave signals by means of first and second oscillation frequencies.
摘要:
A linear mixer circuit with a current amplifier has an excellent linearity by using RF open-load and an improved current amplifier. Therefore, a voltage-current converting stage and a current-voltage converting stage in a conventional mixer circuit can be omitted. Further, by using the RF open-load and the current amplifier together, a current type input signal can be transmitted as it is, and non-linearity due to the voltage-current converting stage and the current-voltage converting stage can be prevented. Furthermore, bias current of the amplifying stage and the switching stage can be separated by using the RF open-load, so that an image frequency can be filtered by the RF open-load.
摘要:
A tunable wideband bandpass filter that can digitally vary the center frequency and bandwidth of a signal to be filtered, and includes a plurality of switched-capacitor banks for varying capacitance and converting the center frequency and bandwidth into a digital signal, and a plurality of inductors provided for inductance to generate the center frequency, the plurality of switched-capacitor banks that may be integrated into a signal chip.
摘要:
An ultra-wideband antenna having an isotropic radiation pattern includes a support plate, a feed line on the support plate, a radiating element connected to the feed line to transmit and receive signals, and a ground plate spaced apart from the feed line and attached to the support plate. The radiating element has at least two intersecting conductive plates.
摘要:
An isotropic antenna system includes a first antenna for transmitting/receiving electric waves when a cover member installed to be capable of being open or closed with respect to a main body is open, a second antenna for transmitting/receiving electric waves when the cover member is closed, and a switching portion for selectively switching at least one of the first and second antennas to a predetermined RF circuit module according to the opening or closing of the cover member.
摘要:
An isotropic antenna system includes a first antenna for transmitting/receiving electric waves when a cover member installed to be capable of being open or closed with respect to a main body is open, a second antenna for transmitting/receiving electric waves when the cover member is closed, and a switch for selectively switching at least one of the first and second antennas to a predetermined RF circuit module according to the opening or closing of the cover member.