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Due to the existence of flash lobe caused by the radome structure, a radar return in general contains clutter component added to target echo. Unlike jammer, clutter is apt to simultaneously coexist with target echo, which hinders a monopulse radar from estimating the angle difference between target echo direction and radar steering direction. In this paper, we propose a clutter estimation algorithm applicable to generalized sidelobe canceller(GSC) based monopulse radar. We show that clutter estimation can be achieved via iterative process of the orthogonal projections. Through simulations, the proposed GSC-based system combined with the clutter estimation can outperform the conventional monopulse system in terms of target angle estimation. [ABSTRACT FROM AUTHOR]

In this development, By using the phase array antenna, the beam around was electronically revolved and the marine fixed type radar of which the detection is possible was made and the check around was tested. There are the risk of the corrosion because of the abrasion of the axis of rotation and salinity with the way that the existing marine pulse radar detects the check by using the mechanical rotation. Besides, the maintenance cost of the magnetron gets to happen by using the detection signal. In this development, The fixed type radar of the low output which revolves electronically around the beam by using the radar signal processing method of the phase array antenna using the phase shifter and FMCW(Frequency Modulation Continuous Wave) method was made. And by using the fixed type radar, the check detection test was conducted. [ABSTRACT FROM AUTHOR]

This paper presents CMOS UWB RFIC based radar system for high speed target detection. The system can achieve resolution of 15 cm and detection range of 15 m. For developed system, single chip CMOS UWB IC is implemented. To reduce the measuring and processing time, envelope detection and equivalent time sampling technique are used. Measurement results show that the bandwidth and center frequency of UWB pulse can be adjusted in the range of 0.5 GHz∼1.0 GHz, 3.5 GHz∼4.5 GHz, respectively. Signal processing time including scan time over 15 m distance is about 150 μsec. [ABSTRACT FROM AUTHOR]

In this paper, the analysis of baluns that are inevitably required to design a differential low noise amplifier, The balun converts a single signal input from the antenna into a differential signal, which serves as an input to the differential amplifier. In addition, it protects the circuit from ESD(Electrostatic Discharge) coming through the antenna and helps with input matching. However, in the case of a passive balun used in general, since the AC signal is transmitted through electromagnetic coupling formed between two metal lines, it not only has loss without gain but also has the greatest influence on the total noise figure of the receiving end. Therefore, the design of a balun in a low-noise amplifier is very important, and it is important to design a balun in consideration of line width, line spacing, winding, radius, and layout symmetry that are necessary. In this paper, the factors to be considered for improving the quality factor of balun are summarized, and the tendency of variation of resistance, inductance, and capacitance of the balun according to design element change is analyzed. Based on the analysis results, it is proved that the design of input balun allows the design of low noise, high gain differential amplifier with gain of 24 dB and noise figure of 2.51 dB. [ABSTRACT FROM AUTHOR]

The accident of the small vessel is increasing due to the growth of the sea and service industry. According to data from National Statistical Office, for 100 ton less than small ship accident, the most of the shipping incident generated in the small ship by 84% of the total shipping incident in 2015. The radar obligatory mounting is enforced to the small vessel in order to conclude this problem. However, the problems including the maintenance cost and transmission power etc. happens high if the existing pulse radar is mounted in the small vessel. In this development, the development is for small ship fixed type radar the object. And in this paper, by using the phase array antenna revolving electronically around the beam, the antenna which it is applicable to the marine fixed type radar which can solve above problem was made and it tested. [ABSTRACT FROM AUTHOR]

The use of small drone platform has become a popular topic in these days but its application for SAR operation has been little known due to the burden of the payload implementation. Drone platforms are distinguished from the conventional UAV system by the increased vulnerability to the turbulences, control-errors and poor motion stability. Consequently, sophisticated motion compensation may be required to guarantee the successful acquisition of high quality SAR imagery. Extremely limited power and mass budgets may prevent the use of additional hardwares for motion compensation and the difficulty of SAR focusing is further aggravated. In this paper, we have carried out a feasibility study of mico-SAR drone operation. We present the image acquisition results from the preliminary flight tests and a quality assessment is followed on the experimental SAR images. The in-flight motion errors derived from the unique drone movements are investigated and attempts have been made to compensate for the geometrical and phase errors caused by motions against the nominal trajectory. Finally, the successful operation of drone SAR system is validated through the focussed SAR images taken over test sites. [ABSTRACT FROM AUTHOR]

This paper presents a jamming detection and suppression algorithm of a frequency-modulated continuous-wave (FMCW) radar altimeter. The radar altimeter measures the noise level at the noise measuring period before the transmitting and receiving period and finds the number of sampled noise data over the jamming threshold for detecting the jamming. For a jamming suppression technique, we design the time domain jamming suppression, transmit/receive power control and frequency hopping methods. To assess more realistic operation, the radar altimeter was performed a field test. Through the field test, we verified the algorithms successfully. [ABSTRACT FROM AUTHOR]

This paper describes the successful development and the performance of X-band 50 W pulsed power amplifier using a 50 W GaN-on-SiC high electron mobility transistor. The GaN HEMT with a gate length of $0.25{\mu}m$ and a total gate width of 12 mm were fabricated. The X-band pulsed power amplifier exhibited an output power of 50 W with a power gain of 6 dB in a frequency range of 9.2~9.5 GHz. It also shows a maximum output power density of 4.16 W/mm. This 50 W GaN HEMT and X-band 50 W pulsed power amplifier are suitable for the radar systems and related applications in X-band. [ABSTRACT FROM AUTHOR]

This paper presents signal processing algorithms of a frequency-modulated continuous-wave(FMCW) radar altimeter and provides a practical assessment technique. The radar altimeter is initially operated in search mode, when the radar altimeter detects a valid altitude, search mode is switched to track mode and a altitude being tracked is displayed. The sweep bandwidth in each mode is a function of altitude to narrow the beat frequency bandwidth. In addition, transmit power and receiver gain in each mode are controlled to compensate for the dynamic range of wide altitude range. To assess more realistic operation, the radar altimeter was tested using the crane setup. The crane test demonstrated that signal processing algorithms described in this paper resulted in a reduced measurement error rate. [ABSTRACT FROM AUTHOR]

An X-band 8×16 dual-polarized active phased array antenna system has been implemented based on the substrate integrated waveguide(SIW) technology having low propagation loss, complete EM shielding, and high power handling characteristics. Compared with the microstrip case, 1 dB less is the measured insertion loss(0.65 dB) of the 16-way SIW power distribution network and doubled(3 dB improved) is the measured radiation efficiency(73 %) of the SIW sub-array(1×16) antenna element. These significant improvements of the power division loss and the radiation efficiency using the SIW, save more than 30 % of the total power consumption, in the active phased array antenna systems, through substantial reduction of the maximum output power(P1 dB) of the high power amplifiers. Using the X-band 8×16 dual-polarized active phased array antenna system fabricated by the SIW technology, the main radiation beam has been steered by 0, 5, 9, and 18 degrees in the accuracy of 2 degree maximum deviation by simply generating the theoretical control vectors. Performing thermal cycle and vacuum tests, we have found that the SIW array antenna system be eligible for the space environment qualification. We expect that the high efficiency SIW array antenna system be very effective for high performance radar systems, massive MIMO for 5G mobile systems, and various millimeter-wave systems(60 GHz WPAN, 77 GHz automotive radars, high speed digital transmission systems). [ABSTRACT FROM AUTHOR]

In this paper, a cancellation technique for electromagnetic waves is realized based on a retrodirective antenna array system. The system re-transmits a signal to the direction of the incoming signal, with the same frequency and opposite phase. For the experimental verification, a 2×2 retrodirective array system is designed and fabricated. Experimental results for a metallic cylinder show as much as 26-dB reduction in reflection. [ABSTRACT FROM AUTHOR]

For detection and parameter estimation, a multicarrier radar should discriminate a channel containing jamming signal and either leave it out or regenerate jammer suppressed target signal. To discriminate jamming channels, we use the angular spectrum of an eigenvector that embeds target echoes and jamming signals. We propose a criteria to discriminate the jammer channels and its basis through mathematical analysis. Moreover, we show some procedures to regenerate the jammer suppressed target echoes. Finally, the validity of the proposed method is demonstrated through simulation results showing improved performance in terms of direction of arrival(DOA) estimation. [ABSTRACT FROM AUTHOR]