• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.3
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• pp.318-325
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• 2019

As satellite communication technology with high efficiency and spatiality evolves, demands of customer for efficient and effective satellite broadcasting services are increasing due to interval reduction of the between satellites, and the limited radio-frequency spectrum resources. Recently, research on antenna that it possible to simultaneously receive multiple signal from various satellites while holding maintain the same number of previous reception channels by using the single reflector has been ongoing. It is necessary to be able to simultaneously receive signals from various satellites in order to maintain the same number of previous reception channels. We suggest a multiband antenna which can be simultaneously and independently receiving Ku band and Ka band satellite broadcasting signals transmitted by three adjacent satellites. We have designed and simulated using commercial design tools TICRA CHAMP and CST MWS to meet the target specifications. It appears that the antenna has -10 dB return loss, and more than 40 dBi directivity gain in Ku band and Ka band respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.96-102
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• 2003

The thermal design of MGSE(Mechanical Ground Support Equipment) panel is performed for thermal vacum thest of Ka-band EQM(Engineering Qualification Model) payload of communications and broadcasting satellite. The thermal environments are predicted to evaluate the performance of transponder equipments in the thermal vacum chamber. SINDA is used to verify the thermal design of the heat pipe layout. Embedded 16 heat pipes in the EQM payload developed for Ka-band trasponder equipments are designded properly. The heat fluz loaded on the external facesheet is 265W/㎡ for the hot platear function test of the traspinder equipments, and the zero heat flux for the cold plateau case. The maxium predicted heat transport capability is 2723 W-cm.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.14-21
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• 2009

In this paper, a Ka-band 10 W power amplifier module with seven power MMIC bare dies is designed and fabricated using MIC technology which combines multiple MMIC chips on a thin film substrate. Modified Wilkinson power dividers/combiners and CBFGCPW-Microstrip transitions for suppressing resonance and reducing connection loss are utilized for high-gain and high-power millimeter wave modules. A new TTL pulse timing control scheme is proposed to improve output power degradation due to large bypass capacitors in the gate bias circuit. Pulse-mode operation time is extended more than 200 nsec and output power increase of 0.62 W is achieved by applying the proposed scheme to the Ka-band 10 W power amplifier module operating in the pulsed condition of 10 kHz and $5\;{\mu}sec$. The implemented power amplifier module shows a power gain of 59.5 dB and an output power of 11.89 W.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.11B
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• pp.1696-1703
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• 2010

Increased demand for military satellite communications system and due to the depletion of resources of existing satellite communications frequencies, Ka-band and EHF-band satellite communication systems is growing demand for development. As a result, the study of rain attenuation mitigation for Ka/EHF-band frequencies has been achieved. The method to compensate rain attenuation on Ka-band(20/30) using the signal power measurement function in Digital Transponder of Next Military Satellite has been proposed in this paper. This method is more effective than generally used method by Beacon and UPC(uplink power control) in giving the precise rain attenuation measurement and correction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.10
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• pp.1104-1114
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• 2008

In the output of a mixer, spurious appears with the desired signal, and a filter is necessary to suppress the spurious. In this paper, the planar filter for Ka-band frequency synthesizer was designed and fabricated. In this procedure, the frequency response becomes asymmetric because of discontinuities at the high frequency. Using this, we designed short-end PCLF by using a individual resonator tuning method. The fabricated 5th-order Ka-band pass filter is compared with the result of EM simulation through measurement. The performance agrees with the simulation. Finally spurious suppression was examined through the measurement of output spectrum of the mixer with the filter.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.141-147
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• 2019

In this paper, a beam pattern performance analysis was performed according to number of array elements and spacing of the phase array antenna. The distance between array elements in an array structure design was reduced due to the electrical length of Ka-band, which increases the number of array elements in applying the aperture. If the number of elements reduce by widening the array distance, the grating lobes of the same size as the main beam will occur in visible region. If the number of array elements should be applied to a system where the number of array elements should be minimized, the analysis was performed on a plan to reduce the number of array elements and minimize degradation of performance, such as beam width and side lobe level.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.3
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• pp.149-155
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• 2019

In this paper, phase shifter has been designed and manufactured to apply to passive phase array seeker for Ka-band and its performance was confirmed. It was designed as a key element for conducting electric beam steering by adjusting the phase of the array element. Insertion loss of less than 1.5dB and phase accuracy of less than $10^{\circ}$(RMS) in operation bandwidth of 1GHz were checked. The performance identified by the actual fabrication was further analyzed by applying the beam pattern analysis based on the array synthesis theory. The effect of the final performamnce of the proven phase shifter on the performance and pointing error and angular accuracy of the passive phase array antenna beam pattern was analyzed. Then, the validation of the proposed phase shifter has been made.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.389-398
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• 2011

In this paper, the design and fabrication of a transmit/receive(T/R) module for Ka-band phased array radar is presented. A 5bit digital phase shifter and digital attenuator were used in common for both transmitter and receiver considering unique Ka-band characteristic. The circulator was excluded in the T/R module and was placed outside T/R module. The transmitting power per element antenna is designed to be about 1 W and the noise figure is designed to be below 8 dB. The designed T/R module RF part has a compact size of $5\;mm{\times}4\;mm{\times}57\;mm$. In order to implement the T/R module, MMICs used in T/R module was separately assessed before assembly of the designed T/R module. The transmitter of the fabricated T/R module shows about 1 W at 5 dBm unit module input power and the receiver shows a gain of about 20 dB and a noise figure of below 8 dB as expected in the design stage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.449-456
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• 2012

Herein, we design a wideband $8{\times}8$ waveguide Butler matrix in order to use in a multi-port amplifiers(MPAs) at Ka-band. To achieve the broadband characteristic, we design a binomial 6-slot 3 dB directional coupler which is used to configure the $8{\times}8$ Butler matrix. The measured results of the fabricated $8{\times}8$ Butler matrix have low insertion loss of less than 0.3 dB, good return loss of over 26 dB and high isolation of over 35 dB within the design bandwidth of 3 GHz.