Abstract: Provided is a FET resistive frequency mixing device having improved RF-LO and IF-LO isolations. The frequency mixing device includes: a field effect transistor (FET), a local oscillation matching circuit connected to a gate of the FET to transfer a local oscillation signal to the gate of the FET, a gate biasing circuit connected to the gate of the FET, a radio frequency (RF) matching circuit having a first terminal connected to a drain side of the FET and a second terminal serving as a RF terminal to receive or output a RF signal, an intermediate frequency (IF) matching circuit having a first terminal connected to the drain side of the FET and a second terminal serving as an IF terminal to receive or output an IF signal, and a series resonance circuit providing a path from the drain of the FET to ground for the local oscillation signal.

Abstract: Provided is a FET resistive frequency mixing device having improved RF-LO and IF-LO isolations. The frequency mixing device includes: a field effect transistor (FET), a local oscillation matching circuit connected to a gate of the FET to transfer a local oscillation signal to the gate of the FET, a gate biasing circuit connected to the gate of the FET, a radio frequency (RF) matching circuit having a first terminal connected to a drain side of the FET and a second terminal serving as a RF terminal to receive or output a RF signal, an intermediate frequency (IF) matching circuit having a first terminal connected to the drain side of the FET and a second terminal serving as an IF terminal to receive or output an IF signal, and a series resonance circuit providing a path from the drain of the FET to ground for the local oscillation signal.

Abstract: Disclosed is a multimode microwave filter including a resonator in which a cavity is formed to generate a resonant mode and a plurality of irises formed on a side surface of the resonator, in which the cavity of the resonator has a rhombus-shaped cross section.

Abstract: Disclosed is a multimode microwave filter including a resonator in which a cavity is formed to generate a resonant mode and a plurality of irises formed on a side surface of the resonator, in which the cavity of the resonator has a rhombus-shaped cross section.

Abstract: Disclosed is a wide band frequency oscillator circuit and oscillation method using a ring voltage-controlled oscillator (VCO). The frequency oscillator circuit includes a low drop-out (LDO) regulator configured to generate an input voltage of a ring VCO, and the ring VCO connected to the LDO regulator and configured to control an oscillation frequency based on the input voltage, wherein the LDO regulator includes a feedback adjustable resistor.

Abstract: A monolithic microwave integrated circuit (MIMIC) for a phased array antenna system, and a phased array antenna system including the MIMIC are provided. The MIMIC includes a first amplifier including a first input terminal and a first output terminal, a second amplifier including a second input terminal and a second output terminal, a first switch connectable to the first input terminal and the second output terminal, and a second switch connectable to the first output terminal and the second input terminal.

Abstract: Provided is a microwave filter system having a feedback structure. The microwave filter system may include an input hybrid coupler configured to output first output signals having a phase difference with respect to an input signal; filters disposed to be in parallel with an output end of the input hybrid coupler, and configured to filter the first output signals; and an output hybrid coupler configured to output second output signals having a phase difference with respect to each of signals filtered through the filters. An output signal of the output hybrid coupler is applied to an input end of the input hybrid coupler along a feedback path.

Abstract: Disclosed is a radio frequency low-loss power divider/combiner and power amplifier including the same, the power divider/combiner including a waveguide and a converter configured to convert an input signal received from an input signal terminal into a plurality of output signals and output the plurality of output signals to a plurality of output signal terminals corresponding to the plurality of output signals through the waveguide, wherein the waveguide includes the converter.

Abstract: Provided is a microwave filter system having a feedback structure. The microwave filter system may include an input hybrid coupler configured to output first output signals having a phase difference with respect to an input signal; filters disposed to be in parallel with an output end of the input hybrid coupler, and configured to filter the first output signals; and an output hybrid coupler configured to output second output signals having a phase difference with respect to each of signals filtered through the filters. An output signal of the output hybrid coupler is applied to an input end of the input hybrid coupler along a feedback path.

Abstract: Disclosed are a multi-beam antenna system and a method of controlling an output power thereof. An embodiment of the present invention includes a beam forming network configured to receive a plurality of signals to be a plurality of beams, to divide each of the plurality of signals to a plurality of divided signals, and to output a plurality of excited signals by adjusting and combining amplitude and phase of each of the plurality of divided signals, an MPA set having a plurality of MPAs configured to receive corresponding excited signals among the plurality of excited signals from the beam forming network and to control output powers of the received excited signals according to communication traffic, and a feed array having a plurality of feeds configured to form a multi-beam by being excited according to the amplitude and phase of the excited signals from the MPA set.

Abstract: Disclosed is a frequency doubler which controls a magnitude of a signal supplied to a virtual ground by adjusting a gain of one-side transistor among transistors receiving differential input signals when outputting a frequency multiplied LO signal through the virtual ground by amplifying the input differential signals by using a differential circuit structure to minimize undesired harmonics characteristics in a frequency doubled signal output by making the magnitudes of two differential signals be the same as each other.

Abstract: A tunable filter device that changes a central frequency and a bandwidth is provided. The tunable filter device may include a body forming a cavity together with a cover, a resonator attached to or integrally formed on a lower surface of the cavity, a frequency-tuning element including a head and a shaft, the shaft passed through the cover and inserted in the resonator, and a cam disposed on the head to contact the head, wherein an insertion length of the shaft is controlled by the cam.

Abstract: Provided is an active true time delay apparatus for delaying a time and producing a gain in a superhigh frequency band using a field effect transistor (FET) and a similar semiconductor device. The active true time delay apparatus may include a delayer configured to delay an input signal for a predetermined length of time using at least one FET element connected in a distributed amplifier structure and an outputter configured to output the delayed input signal, and the delayer is disposed on a transmission line between an inputter and the outputter.

Abstract: A dual-mode filter is provided. A filter may include a cylindrical cavity configured to implement resonance modes with a plurality of different resonant frequencies, and a plurality of slot irises formed on a side of the cylindrical cavity, and the plurality of slot irises may be arranged asymmetrically to each other with respect to the cylindrical cavity.

Abstract: The present disclosure relates to a horn antenna apparatus. The horn antenna apparatus includes: a first horn antenna; and a second horn antennas provided with an input waveguide which is arranged to correspond to an output waveguide of the first horn antenna, wherein the output waveguide of the first horn antenna and the input waveguide of the second horn antenna are connected to be overlapped with each other to form a mode conversion waveguide, and higher modes of a TM11 mode and a TE12 mode are generated in an aperture of an output waveguide of the second horn antenna.

Abstract: The present invention relates to a dual reflector antenna with a hybrid subreflector, and more particularly, to a dual reflector antenna with a subreflector having a structure in which an ellipse and a hyperbola are combined. An exemplary embodiment of the present invention provides a dual reflector antenna including: a main reflector; and a hybrid subreflector which faces the main reflector and has a first structure and a second structure which are combined therein.

Abstract: Provided is a digital attenuation apparatus using a fine tuning function of an attenuation value, which includes: a plurality of digital attenuators connected in series; and an integrated attenuator finely attenuating the attenuation value when output values of the plurality of digital attenuators are input.

Abstract: The present invention relates to a dual reflector antenna with a hybrid subreflector, and more particularly, to a dual reflector antenna with a subreflector having a structure in which an ellipse and a hyperbola are combined. An exemplary embodiment of the present invention provides a dual reflector antenna including: a main reflector; and a hybrid subreflector which faces the main reflector and has a first structure and a second structure which are combined therein.

Abstract: A digital serial-to-parallel converter capable of minimizing a malfunction of a circuit by more stably performing an operation of a D flip flop in implementing a GaAs MMIC digital serial-to-parallel converter and a GaAs MMIC using the same are disclosed. The digital serial-to-parallel converter includes: a converter configured to convert a received clock signal, serial data, and load signal of TTL into a DCFL signal; a plurality of D flip flops configured to transmit the serial data received through the converter to a D flip flop of a next stage by the clock signal received through the converter and output the serial data of the D flip flop of the next stage by the load signal received through the converter; and a plurality of buffers configured to receive the serial data from the plurality of D flip flops to generate and output complementary signals.

Abstract: Disclosed is a waveguide resonator for a band pass filter, which configures a short-circuit stub low-frequency band pass filter in a waveguide resonator to pass a low frequency and reject a stop band, thereby effectively removing undesired spurious or harmonic components on a frequency spectrum.