• Composites Research
• /
• v.20 no.3
• /
• pp.25-30
• /
• 2007

This paper describes the basic design and fabrication of smart skin antenna for phased array applications. The smart skin phased array antenna, of which radiation pattern can be electrically steerable without mechanical rotation, has to meet the both mechanical and electrical performance. The smart skin antenna is a honeycomb sandwich structure to enhance the mechanical performance such as strength, weight and so on. The example of smart skin antenna integrated with radome is designed with the resonant frequency of 5 GHz, circular polarization, 2 by 2 subarray, and a coaxial probe-fed excitation. In addition, the performance of raw microstrip patch antenna uncovered radome is investigate. The fabricated smart skin antenna shows a reasonable performance with gain of 12.2 dBi and frequency bandwidth of 6.4 %.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.41 no.8
• /
• pp.1-7
• /
• 2004

The effect of the sub-optimal beam-forming and the fading channel correlation on the closed loop transmit antenna diversity(CTD) system is investigated in frequency flat Rayleigh fading channels. The fast channel fading prevents the perfect channel estimation at a mobile station, hence the imperfect weight is applied to the antenna branch of transmitter. The weight causes sub-optimalbeam-forming and aggravates the performance of CTD system. The fading correlation or a wireless channel also is one of the factors decreasing the diversity gain. A bit error rate expression for the CTD system is analytically derived as a function of the channel estimation error, the channel correlation coefficient the feedback delay, and fading index. It is shown that the channel estimation error gives more severe effect to the system performance than the channel correlation.

• Structural Engineering and Mechanics
• /
• v.69 no.5
• /
• pp.567-577
• /
• 2019

Guyed steel lattice towers (or guyed masts) are widely used for supporting antennas for telecommunications and broadcasting. This paper presents a numerical study on the static and dynamic response of guyed towers. Three-dimensional nonlinear finite-element models are used to simulate the response. Through performing static pushover analyses and free-vibration (modal) analyses, the effect of different bracing configurations is investigated. In addition, seismic analyses are performed on towers of different heights to study the influence of earthquake excitation time-lag (or the earthquake travel distance between tower anchors) and antenna weight on the seismic response of guyed towers. The results show that the inclusion of time lag in the seismic analysis of guyed towers can influence shear and moment distribution along the height of the mast. Moreover, it is found that the lateral response is insensitive to bracing configurations. The results also show that, depending on the mast height, an increased antenna weight can reduce the tower maximum base shear while other response quantities, such as cables tension force are found to be insensitive to variation in the antenna weight.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.05a
• /
• pp.39-42
• /
• 1999

Adaptive array is using the array of antenna elements spatially and its output is the sum of each antenna elements output signal which is multiplied by the controlled weight coefficients corresponding to each elements. In this paper, for the BPSK and BFSK signals with S/I=2, S/N=10 is applied to the linear array antenna using the LMS & the Kalman filter algorithm. For the 4 elements equidistance linear array antenna system LMS and Kalman filter algorithm was used as the adaptive instruction principles and the application results to the constant amplitude envelope signals such as BPSK or BFSK can be seen that the computer simulation results are very fast in the convergence characteristics of directional patterns and the signal following characteristics.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1536-1541
• /
• 2003

The model of azimuth driving servo system with a flexible antenna in a microwave seeker has been derived in this paper. The validity of the model is verified by comparing the result of the model with that of experiment. It is found that one should consider an antenna as a flexible body in case of modeling the dynamics of the microwave seeker. It is also known that the effect of reducing backlash magnitude for extending the bandwidth in the system with a flexible antenna is smaller than that in the system with a stiff antenna. It is thought that the model-based design optimization of the microwave seeker will become possible by virtue of the derived model, when a weight reduction and a bandwidth extension are required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.9
• /
• pp.872-879
• /
• 2004

The TX/RX broadband L-type circular polarization antenna using LTCC(Low Temperature Co-fired Ceramic) for satellite communication at K, Ka band(20～21 GHz/30～31 GHz) has been presented. This antenna has been analyzed in compensation for LTCC with relative permittivity 5.2 and could have been integrated with RF component. Also antennas on LTCC enable :o reduce loss of RF system due to integrate with RF circuits and to light weight, and thus, generally one can reduce size of the RF system. As the geometry of this antenna presented is made simple by L type of monopole antenna, it is easily manufactured by LTCC progress and enables to reduce loss.

• ETRI Journal
• /
• v.26 no.5
• /
• pp.413-422
• /
• 2004

This paper investigates the impacts of array weight errors (AWE) in an antenna array (AA) on a parallel interference cancellation (PIC) receiver in uplink synchronous and asynchronous direct sequence code division multiple access (DS-CDMA) systems. The performance degradation due to an AWE, which is approximated by a Gaussian distributed random variable, is estimated as a function of the variance of the AWE. Theoretical analysis, confirmed by simulation, demonstrates the tradeoffs encountered between system parameters such as the number of antennas and the variance of the AWE in terms of the achievable average bit error rate and the user capacity. Numerical results show that the performance of the PIC with the AA in the DS-CDMA uplink is sensitive to the AWE. However, either a larger number of antennas or uplink synchronous transmissions have the potential of reducing the overall sensitivity, and thus improving its performance.

• Journal of IKEEE
• /
• v.16 no.1
• /
• pp.62-68
• /
• 2012

The planar microstrip antenna for the safety communication of life at sea is designed and manufactured to effectively receive the emergency wireless signal from the transmitter on the life vest. The proposed microstrip antenna in this paper is easy to make, light weight and cheap compared to other antennas because of printed antenna fabrication. To overcome the narrow bandwidth, large size and low gain characteristics of microstrip antenna, we use the IDMA(Identical Dual Patch Microstrip Antenna with Air-Gap) structure. The proposed antenna was fabricated with the use of 1.6mm FR4 and measured with the 28.7MHz(6.6%) of bandwidth and 3.04dBi of gain at the frequency of 426MHz. To validate the proposed antenna, we experimented the possible distance range at sea using the commercial UHF transceiver module and obtained over 5km distance for stable communication. This antenna can be widely applied to application of the UHF wireless mobile communication.

• Proceedings of the Korea Contents Association Conference
• /
• 2007.11a
• /
• pp.93-96
• /
• 2007

There is increasingly interested in the measurement of antenna's characteristics for one's manufacture according to one's various application. Due to this, the antenna measurement system need be made with more and more great precision. On measuring of the antenna's characteristic, the conventional system handled by human generates the error due to controlling the position of the system by user. Therefore there need be introduced the automatic measurement system of antenna's characteristic. In this paper, we propose image processing algorithm for the automatic measurement system of antenna's characteristic. The proposed algorithm gets image of the standard gain horn antenna in the chamber room, extracts an antenna object from the image, and extracts the parameters for automatic alignment of AUT(Antenna Under Test) and Probe. Also the proposed algorithm gets the error for corrects of slope and distortion of AUT junction due to weight of fitted antenna.

• Journal of the Institute of Convergence Signal Processing
• /
• v.9 no.2
• /
• pp.141-145
• /
• 2008

When the current flows to parallel lines with different length, it is researched that the radiation is occured by the common-mode current radiates, and the small light weight antenna composed of dual elements by using the principle is proposed. However, there is a problem in production about this antenna because this liner antenna is structured by combining with wires. In this paper, we improved this liner antenna, and designed the plane antenna composed of dual elements with different length in the plane printed board to produce and to design easily. Furthermore, the antenna with the wide-band characteristic is also designed in the same board. The radiation pattern is similar to the dipole antenna on account of designing the triangular patch S, the notch and two tapers in patch S, the notch and two tapers in the antenna element. In result, it was able to design the antenna working wider band-width(the bandwidth ratio about 58%, $VSWR{\le}2$).