• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.11a
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• pp.390-391
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• 2022

Recently, SpaceX, private enterprise dealing in space development company, has reported a plan for launching of low earth orbit satellites via Starlink Business, and launched 900 satellites until now. Concretely, it plans tp operate Ku/Ka band satellite, and launch 7,518 of V band satellites for broadband communication. Therefore, wireless communication service for ship will be provided, and various solutions will be offered through the low earth orbit satellites. In this work, we investigated RF characteristics of coplanar waveguide employing periodic 3D coupling structures, and examined its potential for a development of marine radio communication FISoC (fully-integrated system on chip) semiconductor device.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.1
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• pp.8-11
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• 2019

In this paper, a Ku-band 50-W internally-matched power amplifier is designed and fabricated using a CGHV1J070D GaN HEMT from Wolfspeed. To obtain the same magnitudes and phases for the output signals of the unit transistor cells, which constitute a power transistor, a slit pattern and an asymmetric T-junction are used in the input and output matching circuits. The internally-matched power amplifier is fabricated on two different thin-film substrates with relative dielectric constants of 40 and 9.8, respectively, and is measured under pulsed conditions with a pulse period of $330{\mu}s$ and a duty cycle of 6%. The measured results show a maximum output power of 50~73 W, a drain efficiency of 35.4~46.4%, and a power gain of 4.5~6.5 dB from 16.2 to 16.8 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1435-1444
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• 2008

In this paper, we designed a reduced height waveguide(WG) to microstrip mode converter with a short transition length. The mode converter is composed of a mode converter using E-plane probe and a modified impedance transformer. The mode converter was designed using a probe shorted to top of a 50 ohm ridge WG. The modified impedance transformer was designed to connect the mode converter to the reduced height WG. For wide bandwidth operation, the coupling of the two parts was tuned. The structure of the mode converter was optimized for low loss and wide bandwidth, and the optimized mode converter was fabricated. The performance of the mode converter was extracted using the thru and line S-parameters for back-to-back connections, and the connector loss was calibrated. The mode converter has a right angle structure and short transition length, 7.2 mm. The mode converter shows excellent performances; the insertion loss of 0.12 dB at 15 GHz, and the return loss above 10 dB for the full Ku-band.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.26-31
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• 2015

This paper deals with a size-reduced Ku-band waveguide limiter. Basically, it passes the signal from 16.125 GHz through 16.375 GHz, but when excessively high power is injected to the input port, it should change to a bandstop filter. Furthermore, it is required to change to bring attenuation by more than 20 dB and 50 dB over a narrow band and the entire passband, respectively. Therefore, in order to meet this requirement, a limiting device is implemented with multiple PIN-diode posts that enable the limiter to be the bandpass filter and stopband one at the off and on states of the PIN-diode switch, respectively. So, the design goes through the equivalent circuit modelling and the geometry is realized in the accurate electromagnetic analysis CAD tool. Finally, the result is discussed to shed light on whether it complies with the aforementioned requirement.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.830-838
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• 2003

In this paper, TX/RX dual operation microstrip single antenna for satellite communication is designed, analyzed, fabricated and measured. TX/RX frequency ranges are 14.0∼l4.5 GHz, 11.7∼12.75 GHz in respectively and vertical and horizontal polarizations are used for TX and RX. This antenna uses microstrip direct feeding for RX and aperture coupled strip-line feeding for TX and accommodates stacked elements for a high directivity and wide impedance bandwidth. In an analysis of single element, FDTD and MOM was compared and FDTD analysis was more accurate because of the consideration of finite structure and imperfect two ground planes. The proposed structure facilitates generally to an extension of two dimensional array and lower an unwanted radiation by strip-line feed in TX. TX/RX 8${\times}$4 array has a return loss below -10 dB, -14 dB in TX, RX respectively and a gain ranging from 19.1∼20.7 dB in TX, 21.2∼21.8 dB in RX which has a radiation efficiency of 43∼5l %, 52∼57 %.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.4
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• pp.445-452
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• 2019

Today, most detection systems used in the marine industry are the majority of devices operating in the high-power X-band bands. While most detection systems using these frequencies in the X-Band band can expect a wide range of detection performance, they are not suitable for precision detection and have the limitation that they are large and heavy. In this paper, we designed, fabricated and tested an electronic scanner capable of detecting not only the surrounding objects but also the ocean waves at a low power of less than 2W in the 17GHz frequency band of the Ku-Band. A high-performance patch array antenna and Doppler effect were utilized to obtain sufficient detection performance even at low power. As a result of the test, it was confirmed that the performance was sufficiently valuable.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.322-322
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• 2004

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.96-99
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• 2003

This paper presents the development of a Ku-band Low Noise Amplifier with the Noise figure of 1.4dBmax, the gain of 35dB, and the In/Out Return toss of -22dB/-18dB in the frequency range from 14 to 14.5GHz for Satellite transponders. All RF components were assembled using a hybrid technology with 15-mil thin-film substrates. The mechanical and thermal design of the housing was performed considering a vibration and a vacuum of space environment.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.1
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• pp.50-56
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• 2014

In this paper, we proposed a Ku-band antenna that can be mounted on UAV. A proposed antenna structure has small size and light weight. It is considered long distance communication environment(LOS) and equipped UAV. Proposed antenna is designed $16{\times}2$ aperture coupled microstrip patch array antenna for high gain characteristics. In the measurement results, VSWR is less than 1.5 and the gain is over 21dBi in the bandwidth. Mechanical specifications of antenna assembly are ${\phi}250{\times}200mm$ of size and 3kg of weight.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.7 s.110
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• pp.694-705
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• 2006

In this paper, the linear active phased array antenna system operated in Ku DBS band was designed and experimented. The antenna system was composed of sixteen radiating active channels and Wilkinson power combiners with 16-channel inputs, a stabilizing DC bias and phase control board. Electrical beams of the antenna system can be formed by controling the phase-states of 3-bit digital phase shifter inside each active channel by virtue of the phase control board. The amplitude and phase deviations measured between active channels were less than ${\pm}0.8dB$ and ${\pm}15^{\circ}$, respectively, and the noise figure of each active channel was measured less than 1.2 dB in the operating band. The measured performances of the overall antenna system showed the antenna gain of more than 23.07 dBi and the sidelobe level of less than -11.17 dBc, and the bore-sight cross-polarization level of less than -12.75 dBc in the operating band. Also, by phase-controlling active channels, the beam scan patterns at $10^{\circ},\;20^{\circ},\;30^{\circ}$ were measured, and the losses caused by the corresponding beam scanning were 1.1 dB, 2.5 dB and 3.6 dB from the measurements, respectively.