• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.5
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• pp.410-418
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• 2018

This paper describes the design, analysis, and verification tests of the Dual-axis X-band antenna pointing mechanism(XAPM) that has been developed for the Earth observation mission at low Earth orbits. Based on the experience of development and operation of the similar system, we defined the main points and requirements of the system design and confirmed the characteristics of the system through the verification test of the launch and orbit environment test of the engineering qualification model. Through the characteristics and verification techniques of the system acquired during this process, improvement points of the later qualification model are derived.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.447-450
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• 2002

In this paper, we present design methods for a series-fed microstrip patch array operating at X-band frequency. The array consists of 18 rectangular patches connected to 3 quarter-wave impedance transformers. The power divider is designed for the uniform element excitation. The element excitation is then made to be tapered by increasing the input impedance of elements located at array edges. The designed antenna is fabricated and tested. Results of test show a fair agreement with the prediction.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.215-218
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• 2002

Design methods are presented for a broadband corrugated horn antenna operating X/Ku band (7.25-14.5 CHz). The corrugated horn consists of a circular waveguide taper, a mode converter, a waveguide-to-horn transition, and a hem section. Methods of design are presented for each section. The designed antenna shows excellent characteristics over the entire operating frequency range.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.317-322
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• 2005

Synthetic Aperture Radars(SAR) are used mainly for high-resolution imaging of the terrain. This paper describes the 16$\times$16 array antenna designed for an X-band, automobile-based SAR(AutoSAR) system. This antenna has the structure of several layers such as radome, radiators, slots, feed network, and honeycomb cores. Each layer is adhesively bonded to meet different combination of structural and electrical design requirements. Using the Strip-Slot-Foam-Inverted-Patch(SSFIP) structure and dogbone slots, a wide bandwidth and a structural hardness were achieved. Measurement results were compared with simulation results. It was observed that the SAR antenna had a bandwidth of 1.7 GHz, side-lobe levels of less than -20 dB, half-power beamwidth of 5$^{\circ}$, and gains of 25.0 dBi. The observed results show that the designed array antenna is suitable for the broadband AutoSAR system.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.512-514
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• 2007

Even though official G/T for KOMPSAT-2 X-Band downlink acquisition was 32dB/K, KARI performed the data acquisition experiment using 2Am X-Band antenna to check if popular 2Am MODIS receiving antenna can receive KOMPSAT-2 MSC data within acceptable quality level. Through several acquisition tests, it was shown that G/T value of 24dB/K can provide the reliable data BER quality, 10-6 for the above the elevation angle of 10 degree. Some plots for Eb/No versus elevation angle are provided.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.637-642
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• 2020

In this study, the SLB(Sidelobe Blanking)/BLB(Blacklobe Blanking) design of the VHF band radar using the low-frequency band having a relatively larger beam width than the S-band or X-band radar. The antenna of the VHF band has a relatively large beam width, so it is reflected from the side lobe. If the reflected target signal is not processed into sidelobe, the false alarm rate of the radar increases by recognizing it from the main lobe signal. This method of SLB blocking is the elimination of the side lobe signal in the front of the array antenna using the central radiating element of the array antenna, and the blocking of side lobe signal from the antenna rear through BLB receiver block. After completed the radar implementation, The function of blocking of side lobe signals was confirmed through the system unit test by Simulated signal generator. Through this study, it will be used in the implementation of the side-lobe blocking technology of the array antenna for low-frequency band radar with large antenna size and beam width in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.125-129
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• 2010

This paper introduces an X-band microstrip patch array antenna that can be suitable for an energy saving system. The presented patch antenna comprises with 2-element linear array. The antenna is simulated using CST MWS and manufactured using FR-4(h=1.0mm, ${\varepsilon}r=4.4$). The estimated bandwidth, gain and beamwidth are 4%(VSWR$\leq$2), 6.3dBi and about 60o in elevation and 15o in azimuth, respectively. The antenna is fabricated and optimized based on the simulation result and installed on the backside of the sensor circuit and measured. The measured bandwidth, gain and beamwidth are 7%(VSWR$\leq$2), 4.8dBi and about 55o(El)/15o(Az), respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.184-192
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• 2006

Synthetic Aperture Radars(SAR) are used mainly for high-resolution imaging of the terrain. This paper describes the $16{\times}16$ array antenna designed for an X-band, automobile-based SAR(AutoSAR) system. This antenna has the structure of several layers such as radome, radiators, slots, feed network, and honeycomb cores. Each layer is adhesively bonded to meet different combination of structural and electrical design requirements. Using the Strip-Slot-Foam-Inverted-Patch(SSFIP) structure and honeycomb cores, a wide bandwidth and a structural hardness were achieved. Measurement results were compared with simulation results. It was observed that this antenna had a bandwidth of 1.7 GHz, side-lobe levels of less than -20 dB, half-power beamwidth of $5^{\circ}$ and $5^{\circ}$, and gains of 25.0 dBi. The observed results show that the designed array antenna will be applicable to the wideband SAR system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.3
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• pp.329-339
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• 1999

LPXDA(Log-Periodic X Dipole Antenna), consisting of X dipole elements, was proposed as a Log-periodic antenna with short boom length and good Performance relative to LPDA(Log-Periodic Dipole Antenna) . LPXDA for operating frequency band of 500 MHz~l,000 MHz was designed and radiation characteristics of the designed antenna was analyzed by moment method, and compared with LPDA characteristics. The proposed LPXDA, in this paper, was found to have shorter boom length by 20% and better radiation characteristics with variations of frequency relative to the LPDA. The calculated results show good agreement with measurements.

• ETRI Journal
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• v.27 no.6
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• pp.677-684
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• 2005

A phased array antenna was fabricated using four-element ferroelectric phase shifters with a coplanar waveguide (CPW) transmission line structure based on a $Ba_{0.6}Sr_{0.4}TiO_3(BST)/MgO$ structure. Epitaxial BST films were deposited on MgO (001) substrates by pulsed laser deposition. To attain the large differential phase shift and small losses for a ferroelectric CPW phase shifter, an impedance-matching-part adding technique between the effective transmission line and connecting cable was used. The return loss and insertion loss for this techniqueadapted BST CPW device were improved with respect to those for a normal BST CPW device. For an X-band phased array antenna system consisting of ferroelectric BST CPW phase shifters, power divider, dc block, patch antenna, and programmed dc power, the steering beam could be tilted by $15^{\circ}$ in either direction.