• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.1
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• pp.11-17
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• 2020

This study proposes a novel structure for the cross-eye, one of the representative jamming techniques of monopulse sensors. The proposed jammer tranceivers are composed of multi-channels with phased array antenna. We named this structure PRCJ(Phased array Retrodicetive Cross-eye Jammer). In this structure, formulas for calculating cross-eye gain and distance error are derived. We compare the properties of PRCJ with two-element retrodiredtive cross-eye jammer(TRCJ). PRCJ can achieve higher J/S because this structure can steer the spatially combined jamming signal in the direction of the incident monopulse signal. Because of the multiple channels in the phased array, it also increases the degree of freedom of channel matching. Finally, We preform a statistical analysis of the cross-eye gain according to the amplitude and phase errors. From this results, It has been found that PRCJ can get higher cross-eye gain than TRCJ.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.138-145
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• 2010

In this paper, we report the test results of a small-scale prototype that implements an analogue-beam-formed phased antenna array in the E-band. A four-channel dual-conversion receive RF module for 71~76 GHz frequency band has been developed and integrated with a linear end-fire antenna array. Measured performance is very close to the simulated results. An ad-hoc wireless communication system has also been demonstrated. Low BER was measured for an 8PSK data stream at 1.5 Gbps with the receive array beam formed in the direction of arrival of the transmitted signal. To our knowledge this is the first steerable antenna array reported to date in the E-band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1132-1138
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• 2011

In this paper, a method for synthesizing the linear antenna array patterns with broad nulls(BN) at the interference directions is newly presented. Opposit to the conventional methods in which the weights of array elements are optimized for BN control, this method simplifies the control process for multiple BN directions and widths by optimally perturbing the zero positions inherent to Schelkunoff polynomial transformed from the array factor. It is also shown that this method can be easily applicable to the phased array antennas. The proposed scheme is numerically verified by substituting the extracted complex weights into the array factor.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1188-1195
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• 2012

The trend for the development of radar is the active phased-array radar system. The trade-off between the processing speed and the number of the signal process board for the real time signal processing has to be optimized particularly in multichannel radar system. This paper introduces a transmission technique in order to transmit a large amount of received data from an Antenna Part to Signal Process Part. As a result, the number of the S/L board(COTS board) is reduced to one half, and the margin of the data transmission rate is about 2 times higher than the original method.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7A
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• pp.433-439
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• 2003

In this paper, we proposed a novel true time-delay (TTD) feeder for phased array antennas (PAAs) using fiber Bragg gratings (FBGs) and fibers coated with Cr/Au film. This structure requires less number of FBGs than the previously proposed FBG TTD feeders since one FBG is replaced with a metal film reflector in a strand of optical delay line connected to each antenna element and also provides the flexible wavelength selection since the metal film shows wide reflectance spectrum. A TTD for 10 GHz linear PAAs capable of steering beams in three different directions at 0$^{\circ}$and $\pm$30$^{\circ}$has been built. Experimental results on time delays are in good agreement with those calculated at all the steering angles. A 10 GHz linear array antenna with eight antenna elements red from the proposed TTD has been designed and the far-field radiation pattern or this antenna has been obtained by simulation.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.466-472
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• 2003

In this paper, we proposed an optical true time-delay (TTD) feeder system for phased array antennas (PAAs). The system possesses high-speed beam scan capability since, in this scheme, different lengths of fiber delay-lines are selected by optical 2${\times}$2 MEMS switches at high speed. An optical TTD capable of beam scanning in one of eight different directions has been built for 10 GHz linear PAA systems. Experimental results on time delay measurements show that the maximum time delay error is less than 0.2 ps corresponding to a scan angle error of less than 0.84o. We have also designed a 10 GHz linear PAA composed of eight micro-strip patch antenna elements driven by the proposed TTD, and the radiation patterns of this PAA have been analyzed by simulation.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.95-110
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• 2012

The effect of a finite substrate size on the radiation characteristics of a two-element linear E-plane array antenna using microstrip patch antennas is investigated. The average active element pattern characteristics of two-element E-plane array antennas printed on different dielectric constant substrates with various substrate sizes and element spacings are analyzed. Using the average active element pattern, the radiation pattern characteristics of the array antenna versus scan angle is analyzed. The simulation results show that the diffracted fields of surface waves from substrate edges have a significant effect on the radiation characteristics of a 2-element E-plane array antenna. The distance between the center of patch antenna and the substrate edges on the E-plane for the enhancement of radiation characteristics of the array antenna is about $0.35{\lambda}_0$.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.289-294
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• 2002

We propose optical true time-delays (TTDs) for phased-array antennas (PAAs) composed of 2${\times}$2 MEMS switches and fiber delay lines, and implement a TTD which shows a maximum scan angle of $120^{o}$ with $30^{o}$ resolution. Since this structure uses only one fixed wavelength laser diode, it provides several advantages such as easy control, high speed operation, and low cost compared with those of the optical TTDs using tunable laser sources. We design a four element linear PAA using the proposed TTDs at 10 ㎓. Simulation results show that the maximum gain is 11.6 dB at the radiation angle $0^{o}$, 11.2 dB at $\pm$$30^{o}$, and 10.6 dB at $\pm$$60^{o}$.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.643-650
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• 2020

The phased array antenna has an advantage enabling rapid beam aim without the mechanical rotation of the antenna, because it arranges multiple elements in a linear or planer (grid or circular) and electronically controls the phase for each element. The planar array antenna is generally used a grid array and a circular array, and the circular form has the higher resolution comparing to the grid form due to the its structural characteristics. However, a concentric circular array (CCA) or a concentric ring array (CRA) with multiple circular arrays which each has different radius is used in the limited area, because the entire radius should be increased for the circular array with a number of elements. In this paper, we introduce the angle-of-arrival (AOA) estimator for an adaptive beamforming satellite system based on CRA and provide the simulation results for performance evaluation. In addition, simulation results are compared and analyzed to the case for the circular array antenna.