While millimeter-wave (mm-wave) communication can provide abundant spectrum and support high data rate for future 5G systems, its coverage capability in urban environments is a critical issue due to the severe penetration loss. In this letter, we propose a simple scheme to enhance the coverage area of a cell centered with an mm-wave base station. This key idea is to employ multiple passive-reflectors to reflect the mm-wave to the non-lineof-sight (NLOS) regions with low received power levels. In order to improve the received power, a design method for the passivereflector is discussed intensively. Numerical experiment for an outdoor urban environment is presented. The numerical results show that, with the proposed scheme, the coverage radius of an mm-wave cell can be remarkably increased. This indicates that our scheme is an attractive option to alleviate the mm-wave coverage problem for future 5G systems.

We analyze the resolution limit that can be achieved by means of spectral reshaping in optical coherence tomography images and demonstrate that the resolution can be improved by means of modelessly reshaping the source spectrum in postprocessing. We show that the optimal spectrum has a priori surprising "crater-like" shape, providing 0.74 micron axial resolution in free space. This represents ~50% improvement compared to resolution using the original spectrum of a white light lamp.

Interferometric inverse synthetic aperture radar (InISAR) imaging provides complementary information to monostatic inverse synthetic aperture radar (ISAR) imaging. This paper proposes a new InISAR imaging system for space targets based on wideband direct sampling using two antennas. The system is easy to realize in engineering since the motion trajectory of space targets can be known in advance, which is simpler than that of three receivers. In the preprocessing step, high speed movement compensation is carried out by designing an adaptive matched filter containing speed that is obtained from the narrow band information. Then, the coherent processing and keystone transform for ISAR imaging are adopted to reserve the phase history of each antenna. Through appropriate collocation of the system, image registration and phase unwrapping can be avoided. Considering the situation not to be satisfied, the influence of baseline variance is analyzed and compensation method is adopted. The corresponding size can be achieved by interferometric processing of the two complex ISAR images. Experimental results prove the validity of the analysis and the three-dimensional imaging algorithm. Downloaded From: http://remotesensing.spiedigitallibrary.org/ on 05/19/2015 Terms of Use: http://spiedl.org/termsFig. 7 The distribution of dimensions in ISAR image. Tian et al.: Interferometric inverse synthetic aperture radar imaging for space targets.

The argon plasma induced by the L-/C-band high-power microwave (HPM) is investigated theoretically and experimentally. Influences of the microwave power, pulse width, polarization and the plasma electron density on the protection performance of the plasma array against HPM are studied. The results show that the effect of HPM is caused by energy accumulation, with the gas breakdown emerging only after a short time. The attenuation of the wave by the plasma array with the tubes off can reach approximately 23 dB at 1.3 GHz. It can also be obtained that the protection performance of the plasma array against the TE wave is better than that against the TM one. The plasma array shows better protection performance in the L-band than in the C-band. In addition, the attenuation of 5.6 GHz HPM can reach 30 dB when the tubes are turned on in the experiment. The research shows that the plasma array has protection ability against HPM.

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