• The Transactions of the Korean Institute of Electrical Engineers C
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• 제53권9호
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• pp.481-487
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• 2004

The Ku band that has been using for the satellite communication and broadcasting would be changed to K/Ka bands. The satellite system requires the antenna structure to fabricate low loss and small antenna that is able to be integrated with other Rf circuits for both Rx and Tx. So we should design it with dual feed antennas at K/Ka bands, high isolation between two different feeds and broadband circular polarization. This paper proposes the LTCC(Low Temperature Co-fired Ceramic) process for integration with other Rf circuits and the Axial mode of the helical antenna to satisfy those requirements.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제42권1호
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• pp.90-97
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• 2014

In this paper, we have designed the antenna for Korea SAT-5 Satellite Communication which can use Ka band in the earth station. The antenna structure consist of the the dual-offset gregorian reflector that has high gain and efficiency, the corrugated horn that has symmetric radiation patterns and low side lobe levels, the iris polarizer that make circular polarization and the OrthoMode Transducer that separate transmitting and receiving signals. The designed antenna gain is more than 45.7dBi in Tx-band which use LHCP and 42.0dBi in Rx-band which use RHCP. The co-polarized and cross-polarized radiation pattern comply with ITU-R S.580-6 and S.731-1 that are recommended by International Telecommunication Union in the geostationary satellite. The Axial ratio is less than 1.0dB in Tx-band and 1.5dB in Rx-band that meet MIL-STD-188-164A.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제23권3호
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• pp.335-342
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• 2012

A high-isolation Ka-band WR-28 waveguide power combiner is designed and implemented using a resistive septum. The waveguide power combiner developed here is an E-plane T-junction type with a TaN resistive septum inserted in a slit of waveguide junction. The fabricated waveguide power combiner shows a return loss better than -20 dB and an insertion loss less than 0.1 dB. Also the measurement shows isolation levels of 20 dB or more almost all over the band and in particular 25 dB or more below 37 GHz. The amplitude and phase imbalance are measured to be less than 0.1 dB and $2.5^{\circ}$, respectively.

• Journal of the Korean Magnetics Society
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• 제19권6호
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• pp.203-208
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• 2009

Magnetic and Ka-band absorbing properties have been investigated in Ti-Co substituted M-type barium hexaferrites with $BaTi_{0.5}Co_{0.5}Fe_{11}O_{19}$ composition. The ferrite powders were prepared by conventional ceramic processing technique and used as absorbent fillers in ferrite-rubber composites. The magnetic properties were measured by vibrating sample magnetometer. The complex permeability and dielectric constant were measured by using the WR-28 rectangular waveguide and network analyzer in the frequency range 26.5~40 GHz. For the Ti-Co substituted M-hexaferrites, the ferromagnetic resonance is observed at Ka-band (29.4 GHz). The matching frequency and matching thickness are determined by using the solution map of impedance matching. A wide band microwave absorbance is predicted with controlled ferrite volume fraction and absorber thickness.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.441-446
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• 2008

In this papers, a PLDRO(Phase Locked Dielectric Resonator Oscillator) is designed and implemented at the oscillator in which fundamental frequency is 18.3 GHz. The proposed PLDRO so as to improve the PLDRO of the general structure is designed to the goal of the minimize of the size and the performance improvement. Three VCO(Voltage controlled Oscillator) and the power combiner improved the output power. A VCDRO(Voltage Controlled Dielectric Resonator Oscillator) is manufactured using a varactor diode to tune oscillating frequency electrically, and its phase is locked to reference frequency by SPD(Sampling Phase Detector). This product is fabricated on Teflon substrate with dielectric constant 2.2 and device is ATF -13786 of Ka-band using. This PLDRO generates an output power of 5.67 dBm at 18.3 GHz and has the characteristics of a phase noise of -80.10 dBc/Hz at 1 kHz offset frequency from carrier, the second harmonic suppression of -33 dBc. The proposed PLDRO can be used in Ka-band satellite applications

• Journal of the Korea Institute of Military Science and Technology
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• 제16권6호
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• pp.811-818
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• 2013

In this paper, we have designed the elliptical dual offset gregorian antenna which can use Ka band earth station antennas in the fixed-satellite service. The structure of antenna is increasing the antenna gain by decreasing blockage areas and decreasing wind effects by shortening height of the antenna. The corrugate horn antenna for this antenna has symmetric radiation patterns and low side lobe levels that can meet ITU-R envelope. The distribution of electric field on a aperture of main reflector is calculated by an ray-tracing method that use the radiation pattern of the feed horn. The final geometric of antena is decided by choosing the distribution that comply with antenna requirement. The FEKO analysed electrical performance of this antenna. The fabricated antenna has 45.0dBi(@30.0GHz)/41.7dBi(@20.2GHz), high efficiency and low side lobe level that meet ITU-R S. 580-6 envelope.

• Journal of Advanced Navigation Technology
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• 제2권1호
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• pp.11-21
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• 1998

There have been active research efforts in the development of a dual-use millimeter-wave radiometer as an aircraft landing aid in low visibility conditions. In this paper, we constructed a radiometer operating at the Ka-band where it is relatively easy to build RF components. The radiometer is used to collect radiometric signatures of some vehicles and land surfaces. Measured signatures suggest that vehicles with metallic surfaces yield signatures markedly different from nearby land surfaces so that they can easily be detected by a simple radiometer.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제49권1호
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• pp.85-91
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• 2012

In this paper, we implemented a Ka-band frequency synthesizer for millimeter wave seeker. we designed for high frequency resolution and frequency hopping response time in the digital synthesis method which uses DDS(Direct Digital Synthesizer). but frequency bandwidth was limited low frequency because DDS output frequency was limited 1/2 by system clock. thus, frequency synthesizer was converted to Ka-band using the frequency multiplier ${\times}4$ and local oscillator. proposed frequency synthesizer was bandwidth 500MHz, frequency switching time was $0.7{\mu}s$, spurious level was suppressed below -52dBc. phase noise was -99dBc/Hz at offset 100kHz and flatness was ${\pm}1dB$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제20권3호
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• pp.264-272
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• 2009

In this paper, a Ka-band 10 W power amplifier module is designed and fabricated using MIC(Microwave Integrated Circuit) module technology which combines multiple power MMIC(Monolithic Microwave Integrated Circuit) chips on a thin film substrate. Modified Wilkinson power dividers/combiners are used for millimeter wave modules and CBFGC-PW-Microstrip transitions are utilized for reducing connection loss and suppressing resonance in the high-gain and high-power modules. The power amplifier module consists of seven MMIC chips and operates in a pulsed mode. for the pulsed mode operation, a gate pulse control circuit supplying the control voltage pulses to MMIC chips is designed and applied. The fabricated power amplifier module shows a power gain of about 58 dB and a saturated output power of 39.6 dBm at a center frequency of the interested frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제25권4호
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• pp.393-400
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• 2014

In this paper, we have designed the transmitter for earth station terminal operating with military geostationary satellite on Ka-band that is complied with MIL-STD-188-164A. The designed antenna of this terminal is dual-offset gregorian reflector which is consist of corrugated horn and iris polarizer, othermode transducer. This antenna meets radiation pattern and transmit EIRP spectral density requirements in this standard. The designed RF systems of this terminal are consist of Block Up Converter(BUC) converting frequency band from IF to Ka band and SSPA having low-power consumption and compact light-weight using the pHEMT MMIC compound devices. This RF systems applied with VSWR, spurious/harmonic suppression, output flatness and phase noise requirement in this standard.