Mode division multiplexing (MDM) using orbital angular momentum (OAM) is a recently developed physical layer transmission technique, which has obtained intensive interest among optics, millimeter-wave, and radio frequency due to its capability enhance communication capacity while retaining an ultra-low receiver complexity. In this paper, the system model based on OAM-MDM mathematically analyzed it theoretically concluded that such architecture can bring vast reduction in complexity without...

Based on metallic traveling-wave ring-slot structure, an easily realized four-orbital angular momentum (OAM)-mode antenna capable of generating four coaxially propagating waves with OAM modes <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$l$</tex-math></inline-formula> = xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mathbf {-3}$ </tex-math></inline-formula> ,...

A generalized signal model for multiple orbital angular momentum (OAM) mode-based radio communication combined with a novel partial arc sampling receiving (PASR) scheme compactly is proposed and mathematically analyzed. Furthermore, near-field line-of-sight PASR data link using four OAM modes experimentally demonstrated to quadruple the spectral efficiency without adding processing complexity at end. Experiment results show that all channels are recovered bit-error rates below 3.8 × 10 <sup...

Abstract A thermoacoustics imaging system is investigated in this paper to enhance conventional modalities geological subsurface situational awareness applications. While has traditionally been used biological scenarios like breast cancer detection, work aims extend geophysical applications by demonstrating that water‐saturated sand can be distinguished from dry and oil‐saturated based on their amplitude differences. This breakthrough enables the feasibility of monitoring water distribution...

The design of a radio communication system employing orbital angular momentum (OAM) mode multiplexing is described. Rotman lenses followed by circular antenna arrays are used to transmit and receive frequency beams carrying OAM. In our experiment, two 3 × fabricated feed the three-element with certain phase gradients for OAM modes demultiplexing. OAM-carrying number l = +1, 0, -1 generated at 9.7 GHz, each channel an independent data stream 40 Mbit s <sup...

A plane spiral orbital angular momentum (OAM) waves-based 4 × multiple-in-multiple-out (MIMO) communication system for line-of-sight channel is proposed and experimentally demonstrated in comparison with conventional MIMO. The transmitting OAM waves are propagating along the transverse direction; hence there no singularity or divergence problem. Compared MIMO, this could achieve lower spatial correlations a higher capacity gain while antennas as elements of array sorted an ordered sequence....

With the rapid development of high-speed train (HST), HST wireless communication systems have been attracting an increasing amount attention. For design, optimization, and evaluation systems, it is vital to accurate channel model that can mimic non-stationary characteristics links. In this paper, we propose a new geometry-based stochastic (GSCM) for rural macrocell scenarios by exploiting sum-of-frequency-modulated signals method. The time-variant (TV) theoretical autocorrelation function...

Electromagnetic vortices, which describe the orbital angular momentum (OAM) carrying waves with a helical phase front, have recently attracted much interest in radio frequency domain due to their potential applications many diverse areas. In an OAM-based scenario, antenna for OAM mode multiplexing/demultiplexing plays essential role controlling overall system performance. this paper, we demonstrated theoretically and experimentally easily realized based on traveling-wave circular loop...

Conventional millimeter-wave (mm-wave) security screening systems with synthetic or phased arrays require either mechanical electronic scans which are slow, thus not capable to image on-the-move objects. This article presents the 4-D imaging of objects (1-D velocity and 3-D profile) by leveraging cost-effective compressive reflector antennas (CRAs) software-defined mm-wave (SDMMW) multiple-in multiple-out (MIMO) arrays. The CRA creates spatial aperture coding achieve informative measurements...

This letter presents the first experimental results of our three-dimensional (3D) millimeter-wave (mm-wave) Compressive-Reflector-Antenna (CRA) imaging system. In this prototype, CRA is 3D-printed and coated with a metallic spray to easily introduce pseudo-random scatterers on surface traditional reflector antenna (TRA). The performs pseudo random coding incident wavefront, thus adding spatial diversity in region enabling effective use compressive sensing (CS) techniques. fed...

Conventional security screening systems cannot operate in real time and often suffer from false alarms due to the profile-only imaging without further analysis on object material properties. Reflectarrays were recently proposed as devices capable of performing real-time using a single-frequency radar signal. This article presents first physical optics (PO)-based simulation method facilitate design multireflectarray system. Then, an characterization geometrical (GO) is derived for such The...

The topological charge of an electromagnetic vortex beam depends on its wavefront helicity. For mixed beams composed several different coaxial vortices, the spectrum can be obtained by Fourier transform. However, is generally divergent and imperfect. It makes it significant to investigate local charges, especially in radio frequency regime. transform based methods are restrained uncertainty principle cannot achieve high angular resolution mode simultaneously. In this letter, analysis method...

Personnel screening systems having reconfigurable reflect-arrays at microwave frequencies have been widely used in airports, government buildings, and other facilities to detect potential threats concealed under clothing. In order reduce the false-alarm of such systems, a dielectric characterization algorithm using single-frequency is needed. This paper presents new algorithm, based on Physical Optics, which capable characterizing complex constant security threat. The proposed method derive...

This paper presents a new millimeter-wave sensing system used for near-field imaging applications. The presented is composed of parabolic reflector which fed by an array compressive antennas. A Compressive Horn Antenna (CHA) manufactured inserting dielectric piece with pseudo-random geometric pattern inside Pyramidal (PHA). CHA capable performing spectral coding, special interest high-sensing-capacity antenna fabricated using additive manufacturing (3D printing) techniques and then spray...

This paper presents our preliminary results for a three-dimensional (3D) imaging of an on-the-move target using MIMO millimeter-wave (mm-wave) radar, which uses 9 transmitters and 12 receivers. The operating frequency the mm-wave radar is from 70 GHz to 77 GHz. Experimental show that images can be created as under detection moves in front system, combined with 3D video continuous movement target. work paves way towards system used at checkpoints; thus enabling potential threats, enhancing...

Optical and thermal sensors mounted on Unmanned Aerial Vehicles (UAVs) have been successfully used to image difficult-to-access regions. Nevertheless, none of these provide range information about the scene; and, therefore, their fusion with high-resolution mm-wave radars has potential improve performance imaging system. This paper presents our preliminary experimental results a downward-looking UAV system equipped passive optical video camera an active Multiple-Input-Multiple-Output (MIMO)...

An orbital angular momentum (OAM) multiplexed radio data link with the novel partial arc sampling receiving (PASR) scheme is experimentally demonstrated. These four coaxially propagating OAM waves modes of l = -6, -2, +2 and +6 are generated by a Cassegrain antenna based on dual ring-slot radiators. Over 10 m free-space transmission, identical horn antennas uniformly located at π/2 fixed radius 45 cm used to capture overlapped waves. The de-multiplexing then performed digital phase-shift...

In recent year, the use of Unmanned Aerial Vehicle (UAV) has been attracting an increasing amount attention with rapid growing demand high data rate communication service on Internet Things (IoT). However, as a vital fundamental prerequisite research UAV technology, channel model are still at its infancy. Therefore, this paper proposes novel Three-Dimensional (3D) Multiple-Input and Multiple-Output (MIMO) for under Air-to-ground (A2G) environment by introducing Von-Mises Fisher (VMF)...

High-performance millimeter-wave (mm-wave) multiple-in-multiple-out (MIMO) radars have been using efficient multiplexing with increasingly complicated radar waveforms, where conventional hardware architectures suffer from inevitably high design complexity and cost. This article presents a new software-defined mm-wave multistatic imaging system which provides great efficiency flexibility to generate process waveforms. A general block diagram its signal model are proposed use space-time-coded...

Rural-macro (RMa) is an important scenario for fifth generation (5G) deployment, and there a strong diffraction in RMa making it difficult to distinguish between line-of-sight (LoS) non-line-of-sight (NLoS) case. Since the environmental condition closely related dynamic range of channel impulse response (CIR), this paper studies impact on characteristics three dimensional (3D) multiple-input multiple-output (MIMO) channels based 3.5 GHz measurement campaign RMa. The space-alternating...

Millimeter-wave (mm-wave) multiple-in-multiple-out (MIMO) imaging systems have been explored to use more and complicated radar waveforms achieve advanced multiplexing high-performance imaging. As the complexity of increases, conventional radars inevitably suffer from higher design difficulty cost. This work presents a software-defined mm-wave (SDMMW) multistatic by making cost- effective commercial radios (SDRs) additional radio-frequency/mm-wave modules. Due great baseband flexibility SDRs,...

A two-channel RF OAM multiplexed communication system using microwave photonic demultiplexer is experimentally demonstrated. Both of the two OAM-multiplexed OFDM-QPSK signals have been successfully recovered in experiment.