Multi-channel 28-GHz millimeter-wave signal generation on a silicon photonic chip with automated polarization control

We propose and experimentally demonstrate an integrated silicon photonic scheme to generate multi-channel millimeter-wave(MMW) signals for 5 G multi-user applications. The fabricated silicon photonic chip has a footprint of 1.1 × 2.1 mm^2 and integrates 7 independent channels each having on-chip polarization control and heterodyne mixing functions. 7 channels of4-Gb/s QPSK baseband signals are delivered via a 2-km multi-core fiber(MCF) and coupled into the chip with a local oscillator(LO) light. The polarization state of each signal light is automatically adjusted and aligned with that of the LO light, and then 7 channels of 28-GHz MMW carrying 4-Gb/s QPSK signals are generated by optical heterodyne beating. Automated polarizationcontrol function of each channel is also demonstrated with ～7-ms tuning time and ～27-dB extinction ratio.

Non-LOS target localization via millimeter-wave automotive radar

This paper considers the non-line-of-sight(NLOS)vehicle localization problem by using millimeter-wave(MMW)automotive radar.Several preliminary attempts for NLOS vehicle detection are carried out and achieve good results.Firstly,an electromagnetic(EM)wave NLOS multipath propagation model for vehicle scene is established.Subsequently,with the help of available multipath echoes,a complete NLOS vehicle localiza-tion algorithm is proposed.Finally,simulation and experimental results validate the effectiveness of the established EM wave propagation model and the proposed NLOS vehicle localization algorithm.

Study of a millimeter-wave squint indirect holographic algorithm suitable for imaging with large field-of-view

In this paper a millimeter-wave （MMW） squint indirect holographic method is presented, which is suitable for imaging with a large field-of-view. The proposed system employs the squint operation mode to remove the background and twin- image interferences, which achieves a similar effect to off-axis holography but leaves out the large-aperture quasi-optical component. The translational scanning manner enables a large field of view and ensures the image uniformity, which is difficult to realize in off-axis holography. In addition, a corresponding imaging algorithm for the presented scheme is developed to reconstruct the image from the recorded hologram. Some imaging results on typical objects, obtained with electromagnetic simulation, demonstrate good performance of the imaging scheme and validate the effectiveness of the image reconstruction algorithm.

Generation of millimeter-wave sub-carrier optical pulse by using a Fabry-Perot interferometer

A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave （mm-wave） frequency modulation pulse by using a Fabry-Perot interferometer （FPI） for radio-over-fiber （ROF） system. It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot （F-P） cavity, and amplitude decay time and energy transfer efficiency axe related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.

Photonic generation of background-free millimeter-wave ultra-wideband signals

We review the recent progress of photonic generation of millimeter wave （MMW）-ultra-wideband （UWB） signals. To fully satisfy the standard defined by the Federal Communications Commission （FCC）, the baseband signal （background signal） and the residual local oscillator （LO） signal should be well controlled. We discuss several schemes in this work for generating background-free MMW-UWB signals that are fully compliant with the FCC requirement.

LLE-BASED CLASSIFICATION ALGORITHM FOR MMW RADAR TARGET RECOGNITION

In this paper,a new multiclass classification algorithm is proposed based on the idea of Locally Linear Embedding(LLE),to avoid the defect of traditional manifold learning algorithms,which can not deal with new sample points.The algorithm defines an error as a criterion by computing a sample's reconstruction weight using LLE.Furthermore,the existence and characteristics of low dimensional manifold in range-profile time-frequency information are explored using manifold learning algorithm,aiming at the problem of target recognition about high range resolution MilliMeter-Wave(MMW) radar.The new algorithm is applied to radar target recognition.The experiment results show the algorithm is efficient.Compared with other classification algorithms,our method improves the recognition precision and the result is not sensitive to input parameters.

Effective generation of optical quadruple frequency millimeter-wave based on fiber laser using injection rational harmonic mode-locked technique

A method to generate the optical quadruple frequency millimeter-wave with high power efficiency is pro- posed and demonstrated based on the combination of the injection 2nd-order rational harmonic mode- locked fiber ring laser technique and the fiber grating notch filter. In this approach, the fiber Bragg grating notch filter is inserted into the laser cavity to prevent the undesired optical carrier, so that the pump power can be converted to 2nd-order harmonic wave more efficiently. In our experiment, the power efficiency of optical quadruple frequency millimeter-wave （40 GHz） generation is ten folds of that of our previous method based only on the rational harmonic mode-locked technique.

Leaky-Wave Antennas for 5G/B5G Mobile Communication Systems:A Survey

Since leaky-wave antennas(LWAs)have the advantages of high directivity,low loss and structural simplicity,LWAs are very suitable for designing millimeter-wave(mmW)antennas.The purpose of this paper is to review the latest research progress of LWAs for 5G/B5G mobile communication systems.Firstly,the conventional classification and design methods of LWAs are introduced and the effects of the phase constant and attenuation constant on the radiation characteristics are discussed.Then two types of new LWAs for 5G/B5G mobile communication systems including broadband fixed-beam LWAs and frequencyfixed beam-scanning LWAs are summarized.Finally,the challenges and future research directions of LWAs for 5G/B5G mobile communication systems are presented.