• Journal of the Korean Society of Costume
• /
• v.26
• /
• pp.163-173
• /
• 1995

The purpose of this study is to investigate the Ku which was worn by nomadic tribes which was Khitai, Mongols and Manchus. The results of this study can be summarized as follows. 1. The fur clothes were very important clothes that nomadic tribes put on in order to protect them against the cold. The Ku was an outfit for protection against the cold. It was made of ani-mal fur and its style was tight sleeve and long dress. 2. The Ku was worn in all social classes including emperor, nobles and the masses in ancient China and Asia dynasty. After the nomadic tribes estabilished dynasty in China the style of Ku was changed. All kinds of animal fur was used to make the Ku but the volume of fur, kinds and colors were classified severely by their social position. In Khitai dynasty the Ku was worn in same style. But the emperor wore the Ku of silver marten. The noble class wore the Ku of purple, black and blue marten and silver squirrel skin. The masses wore the Ku of the other colors marten, sheep, squirrel and dessert fox skin. In Mongol dynasty, the emperor wore the Ku of purple marten, silver squirrel, silver fox and black fox skin. The nobles wore the Ku of the other colors marten and squirrel. The masses wore the Ku of degraded animal fur. Before the Manchus estabilished the varient races dynasty in China, the rich man preferred the Ku of marten, squirrel, fox, goat furs. But the poorman preferred the Ku of cow, horses, pig, sheep, cat, dog, snake and deer skin. After the manchus conquered the China, the manners of dress were changed. Generally the fur did not appear in right side of garment, but high quality or noble fur appeared outside. Sometimes the inside or outside of Ku was made of silk fabrics and sleeves, neck-band was made of the high quality fur.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.8
• /
• pp.7-15
• /
• 1994

In this paper, the directional coupler for Ku-band, which is designed is of the crossguide type with a coupling value of about 3-dB. The apertures chosen for this design are crosses. We used polynomial approximations of rounded end slot to obtain the electric and magnetic polarizability of crossed-slot and compared the results with Cohn's experimental results. The optimized dimensions and positions of the cross aperture are obtained by a trial-and-error reiteration of the program. This paper presents the measurement results for the designed coupler. The very flat coupling shows a total variation of only 29.80$\pm$0.04dB for the design frequency ranges of 12.25GHz-12.75GHz. The measured minimum directivity is 25dB. The aperture attenuation for the finite diaphragm thickness is about 2dB pr 0.5mm, which is in agreement with the theoretical value. The transmission loss and input return loss at center frequency are 0.0564dB and 48.16dB respectively. We obtained the measured minimum directivity of the coupler. Whose apertures are both circles is better than that containing holes in the performance of directivity.

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

• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2034-2036
• /
• 2004

In this paper, a low noise amplifier (LNA) in receiver of Low Noise Block Down Converter (LNB) for direct broadcasting service (DBS) is implemented by using GaAs HEMT. The LNA is designed for operation between 10.7GHz-12.7GHz. The LNA consists of input, output matching circuits, DC-blocks and RF-chokes. Simulation result of the LNA shows that a noise figure is less than 1.4dB and a gain is greater than 9.2dB in the bandwidth of 10.7 to 12.7GHz with good flatness of 0.1dB.

• ETRI Journal
• /
• v.27 no.3
• /
• pp.243-249
• /
• 2005

A mobile antenna for multimedia communications with Ku-band geostationary satellite KOREASAT-3 and JSAT-2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non-periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2001.05a
• /
• pp.13-18
• /
• 2001

This paper deals with finite element analysis for free vibration and forced sine vibration of Ka- and Ku- bend antenna structures using MSC/PATRAN/NASTRAN. The structures are designed to satisfy minimum resonance frequency requirement in order to decouple the dynamic interaction of the satellite with the spacecraft bus structure. From the forced sinusoidal vibration, we have observed output acceleration versus input in X-,Y- and Z- direction, based on base excitation using large mass method. The results of finite elements analysis can be used as the reference data for the experimental test of satellite antenna, resulting in the reduction of cost and time by predicting and complementing experimental data.

• 한국정보통신설비학회:학술대회논문집
• /
• 2002.08a
• /
• pp.31-34
• /
• 2002

본 논문은 Ku-band(12.4-18 GHz) 위성통신 시스템 및 이동통신 중계기용 송수신부에 사용되는 고안정도 전압제어 유전체 공진기(Voltage Controlled Dieletric Resonator Oscillator)의 설계 및 제작에 대해 논하였다. 유전체 공진기(Dielectric Resonator)의 등가회로 모델을 이용하여 유전체 공진 발진기(Dielectric Resonator Oscillator)를 설계 알고리즘화 하였다. 유전체 공진 발진기와 바렉터 다이오드를 이용하여 13.4 GHz의 전압 제어 유전체 공진 발진기를 제작하였다. 이때의 출력 전력은 +12dBm이고 위상잡음은 offset 주파수 100kHz에서 -105 dBc/Hz로 측정되었다.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.32A no.9
• /
• pp.1229-1235
• /
• 1995

In this paper an elliptic response dual-mode 4-pole bandpass filter was designed, manu-factured, and tested. A dual-mode filter having two stages cascaded double-tuned cavities which are resonant in two independent orthogonal TE113 circular-cavity modes and provide a bandpass response. A 4-pole dual-mode elliptic function bandpass filter has a center frequency of 14.022 GHz with a bandwidth of 36 MHz which is the first channel of the KOREASAT up-link frequency. The measured experimental results of a dual-mode filter are 1 dB insertion loss in the passband and 20 dB out-of-rejection.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2003.11a
• /
• pp.100-103
• /
• 2003

A Ku-band Push-push VCO for low cost applications is proposed. The proposed push-push oscillator achieves a wide tuning range in Ku-band by the collector bias tuning instead of extra varactor diodes. The measurement shows a wide tuning range of 900MHz, fundamental suppression of -30dBc and good phase noise of -115dBc@1MHz offset.

• Transactions on Electrical and Electronic Materials
• /
• v.18 no.1
• /
• pp.16-20
• /
• 2017

A RF-MEMS (radio-frequency microelectromechanical-system) based DPDT (double pole double throw) switch for the Ku band has been designed and analyzed for this article. The switch topology is based on the FG-CPW (finite ground-coplanar waveguide) configuration of a microstrip-transmission line. An FEM-based multiphysics solver is used for the evaluation of the spring constant, stress distribution, and pull-in voltage regarding the requirements of the switch-beam unit. The electromagnetic performance of the switch is investigated for a $675{\mu}m$ thick silicon substrate. For the operational frequency of 14.5 GHz, an insertion loss better than -0.3 dB, a return loss better than -40 dB, and input/output- and output-port isolations better than -35 dB are achieved for the switching unit.