• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.1
• /
• pp.90-97
• /
• 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 Communications and Information Sciences
• /
• v.37 no.8C
• /
• pp.637-644
• /
• 2012

In this paper, a new compact power divider is suggested. Instead of the quarter wavelength transmission line(TX-line)s for the branches of the conventional Wilkinson's power divider design method, we use our composite right- and left-handed(CRLH) TX-line zeroth order resonator(ZOR) bandpass filters of one twelfth wavelength and reduce the physical length of the power divider. Besides, the filters in the branches can secure the passband for power-division. To validate the proposed power divider, we take an L-band for millitary satellaite transponder as the test case and the performances of the circuit and full-wave simulation results with the CRLH properties of the structure are shown with the dispersion curve and E-field at the ZOR. The measurement is compared with the simulation results. Also, the size reduction effect by the proposed scheme is addressed

• Journal of Korean Medicine Rehabilitation
• /
• v.25 no.3
• /
• pp.81-90
• /
• 2015

Objectives This study was designed to compare the effects Gwibi-tang herbal-medication with Danggwisusan herbal-medication for patients with acute cervical and lumbar sprains due to a traffic accident. Methods This study was carried out on 119 acute cervical & lumbar sprain patients by traffic accident. We divided these patients into 2 groups. Group A was treated with Gwibi-tang and Group B was treated with Danggwisusan three times a day for three days. Each patient was treated with acupuncture, physical therapy and two types of herbal-medication. We measured the numerical rating scale (NRS) at two time points : pre-treatment (Tx). and post-Tx. Results 1. The NRS scores significantly decreased after treatment in all patients. 2. The changed NRS scores of nuchal pain showed a borderline significant difference between Group A and Group B (p=0.067). 3. In sub-group analysis, Gwibi-tang showed a greater effect on NRS scores of lumbago pain in female patients (p=0.068) and patients under 30s (p=0.054) compared to Danggwisusan. Conclusions In this study, both types of herbal-medication; Gwibi-tang and Danggwisusan were highly effective on acute cervical and lumbar sprain patients. Especially Gwibi-tang (Group A) was more effective than Danggwisusan (Group B) in reducing the initial nuchal pain. Also Gwibi-tang was more effective for lumbago pain in female and patients under 30s.

• The Journal of Korean Medicine
• /
• v.27 no.3 s.67
• /
• pp.227-240
• /
• 2006

Objective: To know the recurrence rate of paranasal sinusitis in adults using follow-up investigations. Method: Data was collected from 37 patients who were treated in the Department of Ophthalmology & Otolaryngology & Dermatology, Kangnam Oriental Medical Hospital from 2001-10-01 to 2005-05-31 for chronic paranasal sinusitis in adults over 21 years of age. Results & conclusions: 1. The males made up 51.4% and females made up 48.6%. The recurrence rate was 78.4%. 2. By residence, 78.4% lived in apartments; 21.6% lived in houses. 3. Of the main symptoms, nasal obstruction was the most common. 4. The duration of the disease was within 1 month to 40 years; the group with difficulties within the last 5 years made up the largest group. 5. The patients who had chronic nasal family histories made up 40.5%; Patients who didn't have chronic nasal family histories made up 59.5%. 6. In regards to the period of Tx distribution. the group treated within 4 weeks made up the largest group at 54.1%. 7. As far as methods of Tx distribution, the group of patients treated with herbal medicine and acupuncture were larger (62.2%) than the group treated with only herbal medicine (37.8%). 8. The most common nasal condition symptom in patient histories was chronic rhinitis. 9. The most frequent areas affected by paranasal sinusitis on PNS images were the lateral maxillary sinus, the unilateral maxillary sinus and the ethmoidal sinus. 10. The number of patients who drank little was larger (75.7%) than the number of drinking patients(24.3%); There were more non-smoking patients (78.4%) than smoking patients(16.2%). 11. The patients who slept for 6-7 hours made up the larger group (40.5%). 12. The number of patients who preferred warm water was larger making up 54.1 %; the number of patients that preferred cool water made up 21.6%. 13. The patients who had a common cold 3-5 times a year was the largest group at 54.1%.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.8 no.5
• /
• pp.29-34
• /
• 2008

In this paper, we propose the channel sounding scheme which improves the reliability and performance of communication link and mitigate the fading effect of channel in MTMO-OFDM system having correlation between Tx and Rx antennas. And we estimate the channel propagation characteristics of channels between the transmitter and receiver with CS scheme by measuring the channel propagation characteristics using sounding signal. Multi agent system models can be used to analyze the path of the system within any time frame. Further, using this proposed method, we can increase the channel capacity by simple calculation in receiver and transmitter and allocate the optimal power by channel information in transmitter. Also, the increment of channel capacity using the prorposed method is induced as the number of antenna is increased. So, we can anticipate the performance improvement with the presented scheme in more complicated Tx and Rx antenna system.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.43 no.1 s.343
• /
• pp.143-148
• /
• 2006

This paper presents a high isolation and power-handling single-pole double-throw(SPDT) switch for dual band wireless LAN applications. The switch circuit has asymmetric topology which uses stacked-gate to have high power-handling and isolation for the Tx path. The proposed SPDT switch has been designed with optimum gate-width, bias, and number of stacked-gate FET. This SPDT switch has been implemented with $0.25{\mu}m$ GaAs pHEMT process which has Gmmax of 500mS/mm and fmax of 150GHz. The designed SPDT switch has the measured insertion loss of better than 0.9dB and isolation of better than 40dB for the Tx path and 25dB for the Rx path and the high power handling capability with PldB of about 23dBm for control voltage of -3/0V. The fabricated SPDT switch chip size is $1.8mm{\times}1.8mm$.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.36D no.12
• /
• pp.21-30
• /
• 1999

Several kinds of design method for the hairpin type band-pass filter have been reported. The conventional design methods have some restrictions in characteristic impedance of coupled line section, which provide complexities to designer. In this paper, the novel design formulas for the hairpin type band pass filter have been derived and proposed to resolve the problems of the reported design methods. By employing the equivalent circuit of the coupled line section and band pass filter design theory, the design procedures and formulas are derived. The hairpin type RX/TX band pass filters for the IMT-2000 service have been designed, fabricated with duplexer configuration, and then measured to show the validity of the proposed design method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.5
• /
• pp.765-776
• /
• 2001

In this paper, a shaped offset gregorian antenna is electrically designed for Ku band FSS antennas of the domestic communications and broadcasting satellite which will be launched in the near future. For this, a design procedure for shaped offset gregorian antennas is described in detail, and a satellite antenna is designed by using the described design procedure. The radiation characteristics of the designed antenna are evaluated and compared with the design goals. The designed antenna is found to have 1.2$^{\circ}C$ beamwidth, 38.57 dBi EOC gain, and 43.19 dBi gain at Tx frequency 12.25 GHz and 1.08$^{\circ}$ beamwidth, 38.12 dBi EOC gain, and 44.11 dBi gain at Rx frequency 14.0 GHz. And also, side lobe levels and cross-polarization levels are less than -30 dB and -33 dB, respectively. From these results the designed antenna is found to be able to use for the domestic satellite FSS antennas.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.3
• /
• pp.284-290
• /
• 2004

In this paper, two types of thin nim bulk acoustic resonator(TFBAR) ladder filters are desisted and fabricated to analyze the effects of on-wafer inductor integration. To suppress the overmode phenomenon a 1 $\mu\textrm{m}$ thick air-gap is fabricated under the TFBAR and aluminum nitride is used for piezoelectric material, while platinum is employed for the top and bottom electrodes. The Tx filter in a duplexer, which usually has a steeper skirt characteristics o the right side of the passband, is designed with four serial and two shunt resonators, namely, a 4/2 stage. Similarly, the Rx filter is devised with a 3/4 stage to create a mirrored image of the Tx filter passband characteristics. Fabricated on-wafer spiral inductors with underpass reveals the Q factor of 5～9 at 2 ㎓. Inductor integrated filters have approximately 10 to 12 ㏈ out-of-band rejection improvement, when compared to the original filters.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.1
• /
• pp.119-124
• /
• 2010

The MAC layer in ad-hoc network which makes network of nodes without infrastructure for a time has became an issue to reduce delay, allocate fairly bandwidth, control TX/RX power and improve throughput. Specially, the problem to reduce power consumption in ad-hoc network is very important part as ad-hoc devices use the limited battery. For solution of the problem, many power control algorithms, such as distribute power control, PCM (Power Control MAC) and F-PCF (Fragmentation based PCM), are proposed to limit power consumption until now. Although the algorithms are designed to minimize power consumption, the latency communication zone is generated by power control of RX/TX nodes. However the algorithms don't suitably reuse the space. In this paper proposes the algorithm to improve data throughput through Spatial Reuse based on a power control method.