Abstract: Provided is a dielectric waveguide filter. The filter includes: a multi-layered structure of dielectric substrates having first and second ground planes at its top and bottom; first, second, and third waveguide resonators disposed at multiple layers within the multi-layered structure; converters for signal transition between input/output ports and the first and third waveguide resonators; first vias for forming the first, second, and third waveguide resonators; and second vias disposed at a boundary surface of the first waveguide resonator and the third waveguide resonator.

Abstract: Provided is an optical module used in a communication system employing a radio over fiber (ROF) technology delivering a radio frequency (RF) signal through an optical fiber. The optical module includes: an optical device; a signal line for transporting a radio frequency (RF) signal input from an external circuit to the optical device; and a resistor separately disposed from the signal line and having one end connected with the optical device, wherein the input impedance seen from the signal line is matched by the resistor. A bias voltage supplied to operate the optical device is applied through an inductor connected to the signal line between the optical device and a filter. Here, the filter formed by a pattern of the signal line prevents the bias voltage from being supplied to the external circuit. In order to amplify the RF signal input from the external circuit, an amplifier may be connected between the external circuit and the filter.

Abstract: Provided is a microwave module having a converter for improving transmission characteristics in a millimeter-wave band. When a microstrip transmission line and a conductor-backed coplanar waveguide (CBCPW) transmission line are connected by wire bonding, a change in impedance caused by wire bonding and an abrupt change in electric field components between the two transmission lines are reduced by the converter. Therefore, insertion loss and return loss are reduced, and transmission characteristics in a millimeter-wave band are improved.

Abstract: Provided is a broadband microstrip-waveguide transition apparatus operating in a millimeter waveband. The millimeter-wave band broadband microstrip-waveguide transition apparatus includes a slot for transferring an electromagnetic signal propagating along a microstrip line, a main patch positioned between the slot and a waveguide and resonating from the signal transferred from the slot, and a parasitic patch positioned between the main patch and the waveguide and resonating together with the main patch. According to the millimeter-wave band broadband microstrip-waveguide transition apparatus, it is possible to transfer a signal from the microstrip line to the waveguide, and to increase a resonance bandwidth to a broadband level.

Abstract: Provided is a microwave module having a converter for improving transmission characteristics in a millimeter-wave band. When a microstrip transmission line and a conductor-backed coplanar waveguide (CBCPW) transmission line are connected by wire bonding, a change in impedance caused by wire bonding and an abrupt change in electric field components between the two transmission lines are reduced by the converter. Therefore, insertion loss and return loss are reduced, and transmission characteristics in a millimeter-wave band are improved.

Abstract: A narrowband microstrip type bandpass filter adapted for a home network, telematics, an intelligent traffic system, and a satellite Internet, includes: an input terminal for receiving a predetermined signal; an output terminal for outputting a selection signal in a characteristic band; a first resonator electrically coupled with at least a portion of the input terminal; a second resonator electrically coupled with at least a portion of the first resonator; and a third resonator electrically coupled with at least a portion of the output terminal and the second resonator. A magnetic coupling is provided using a cross coupling gap or a cross coupling line between non-adjacent resonators, so that a pattern can be simplified by optimizing the design and the manufacturing process to provide low-cost millimeter-wave parts. The manufacturing cost can be reduced by miniaturizing the parts, and the mass production can be readily realized.

Abstract: Provided is an air cavity module for a planar type filter operating in millimeter-wave frequency bands. The air cavity module includes: the planar type filter operating in the millimeter frequency bands; an air cavity having open side and top surfaces to mount the planar type filter therein; and an air cavity cover closing up the open top surface of the air cavity to allow the transmission of signals from and into the planar type filter. The air cavity module can lessen both transmission loss and radiation loss to improve the characteristics of the filter that operates in the millimeter-wave frequency bands.

Abstract: Provided are a dielectric ceramic composition of forsterite system for microwave and millimeter-wave application and a method for forming the same. Here, the dielectric ceramic composition having a small dielectric loss is used for communication devices used at microwave and millimeter-wave bands. The dielectric ceramic composition includes forsterite (Mg2SiO4) as a main element and titanium oxide (TiO2), which is partially substituted for silicon (Si) in forsterite. The dielectric ceramic composition is obtained by using 56 to 57 wt % of MgO, 33 to 42 wt % of SiO2, and 1 to 11 wt % of TiO2, and adding an additive including Li ions as a sintering aid for improving a sintering characteristic. The dielectric ceramic composition is formed by mixing MgO, SiO2, and TiO2, calcining the mixture to form forsterite powder, adding an additive including Li ion, for example, Li2CO3, and shaping and sintering the mixture.

Abstract: Provided is a broadband microstrip-waveguide transition apparatus operating in a millimeter waveband. The millimeter-wave band broadband microstrip-waveguide transition apparatus includes a slot for transferring an electromagnetic signal propagating along a microstrip line, a main patch positioned between the slot and a waveguide and resonating from the signal transferred from the slot, and a parasitic patch positioned between the main patch and the waveguide and resonating together with the main patch. According to the millimeter-wave band broadband microstrip-waveguide transition apparatus, it is possible to transfer a signal from the microstrip line to the waveguide, and to increase a resonance bandwidth to a broadband level.

Abstract: The present invention relates to a microstrip band pass filter and, more specifically, to a microstrip band pass filter using end-coupled stepped impedance resonators that can be used in a millimeter wave band, wherein the microstrip band pass filter comprises: a dielectric substrate; a conductor plate located on a lower surface of the dielectric substrate; and an input terminal, a plurality of SIRs and an output terminal located on an upper surface of the dielectric substrate in series, wherein the input terminal, the plurality of SIRs and the outputs terminal are conductors and end-coupled through gaps, whereby the microstrip band pass filter has a good attenuation characteristic and a narrowband characteristic, and is insensitive to the manufacturing error, and a fine frequency transition can be made without distortion just with width adjustment of the low impedance transmission line of the SIR.

Abstract: A dictionary coupler using a non-radiative dielectric waveguide is disclosed. Particularly, a millimeter wave band non-radiative dielectric waveguide directional coupler using a multiple-hole structure in which two parallel NRD waveguides located between upper and lower conductive plates and a conductive plate having a multiple-hole structure is inserted between two NRD waveguides to couple electric and magnetic waves of an electric field component or a magnetic field component is provided.

Abstract: A S/N enhancer using the magnetostatic wave signal. The S/N enhancer comprises a balun coupler for dividing an input signal into a first and second signals having the same power, the second signal having the phase difference of 180 degree with respect to the first signal; a saturation magnetostatic wave filter for receiving the first signal output from the balun coupler, converting that into a magnetostatic wave signal, and oppositely converting the magnetostatic wave signal, wherein the power of the magnetostatic wave signal is saturated if the first signal has the power of equal to and more than that of a noise signal; a delay line having the linearity to transmit the second signal output from the balun coupler; and a power synthesizer for synthesizing the respective signals output from the saturation magnetostatic wave filter and the delay line.

Abstract: A microstrip cross coupling bandpass filter includes an input port, an input resonator, an output port, and an output resonator. The input port and the input resonator are electric-coupled, and the output port and the output resonator are electric-coupled. A cross coupling gap corresponding to the distance between the input and output resonators forms magnetic coupling. The bandpass filter further includes a cross coupling line electric-coupled with the input and output ports. The cross coupling gap generates an attenuation pole on the high side of a passband. The attenuation frequency of the attenuation pole can be varied with the distance of the cross coupling gap. The cross coupling line generates an attenuation pole on the high and low sides of the passband.

Abstract: Provided are a dielectric ceramic composition of forsterite system for microwave and millimeter-wave application and a method for forming the same. Here, the dielectric ceramic composition having a small dielectric loss is used for communication devices used at microwave and millimeter-wave bands. The dielectric ceramic composition includes forsterite (Mg2SiO4) as a main element and titanium oxide (TiO2), which is partially substituted for silicon (Si) in forsterite. The dielectric ceramic composition is obtained by using 56 to 57 wt % of MgO, 33 to 42 wt % of SiO2, and 1 to 11 wt % of TiO2, and adding an additive including Li ions as a sintering aid for improving a sintering characteristic. The dielectric ceramic composition is formed by mixing MgO, SiO2, and TiO2, calcining the mixture to form forsterite powder, adding an additive including Li ion, for example, Li2CO3, and shaping and sintering the mixture.

Abstract: The present research provides a high-density magnetic ceramic composition for microwave application and a preparation method thereof. The magnetic ceramic composition of this research includes Yttrium iron garnet (YIG, Y3Fe5O12) as its basic element and a little amount of additional element, silicon oxide (SiO2), which is expressed as: Y3Fe5O12+x SiO2 (0.05?x?5 mol %). The magnetic ceramic composition is prepared by measuring proper amounts of ferric oxide (Fe2O3), yttrium oxide (Y2O3) and SiO2, mixing them, calcining the mixture, and molding and sintering them. Since the magnetic ceramic composition of the present research has very little magnetic loss, it can be used in components for communication in a microwave band, usefully.

Abstract: A S/N enhancer using the magnetostatic wave signal.

Abstract: A dictionary coupler using a non-radiative dielectric waveguide is disclosed. Particularly, a millimeter wave band non-radiative dielectric waveguide directional coupler using a multiple-hole structure in which two parallel NRD waveguides located between upper and lower conductive plates and a conductive plate having a multiple-hole structure is inserted between two NRD waveguides to couple electric and magnetic waves of an electric field component or a magnetic field component is provided.

Abstract: A S/N enhancer using the magnetostatic wave signal is disclosed.

Abstract: The present research provides a high-density magnetic ceramic composition for microwave application and a preparation method thereof. The magnetic ceramic composition of this research includes Yttrium iron garnet (YIG, Y3Fe5O12) as its basic element and a little amount of additional element, silicon oxide (SiO2), which is expressed as: Y3Fe5O12+x SiO2 (0.05≦x≦5 mol %). The magnetic ceramic composition is prepared by measuring proper amounts of ferric oxide (Fe2O3), yttrium oxide (Y2O3) and SiO2, mixing them, calcining the mixture, and molding and sintering them. Since the magnetic ceramic composition of the present research has very little magnetic loss, it can be used in components for communication in a microwave band, usefully.

Abstract: A S/N enhancer using the magnetostatic wave signal is disclosed.