Li-an Bian

Capacity analysis of OAM multiplexing system for radio communications

The orbital angular momentum (OAM) applied to wireless communication has been verified feasibly. To achieve better performance, the influence of both OAM modes at the transmitting side and antenna configurations at the receiving side on system capacities is researched by exploiting the method of singular value decomposition (SVD). It is found finally that, non-uniform receiving array configuration can also achieve better results. Moreover, the performance may be poorer with more receiving antennas, due to the emergence of correlation. Besides, to further improve the performance, optimizing power allocation should be considered.

Tunable Coupled-Resonator-Induced Transparency in a Photonic Crystal System Based on a Multilayer-Insulator Graphene Stack

We achieve the effective modulation of coupled-resonator-induced transparency (CRIT) in a photonic crystal system which consists of photonic crystal waveguide (PCW), defect cavities, and a multilayer graphene-insulator stack (MGIS). Simulation results show that the wavelength of transparency window can be effectively tuned through varying the chemical potential of graphene in MGIS. The peak value of the CRIT effect is closely related to the structural parameters of our proposed system. Tunable Multipeak CRIT is also realized in the four-resonator-coupled photonic crystal system by modulating the chemical potentials of MGISs in different cavity units. This system paves a novel way toward multichannel-selective filters, optical sensors, and nonlinear devices.

Wideband, circularly polarized, crossed, bowtie dipole antenna for navigation satellite system

In the article, a wideband, high-efficient, circular polarized(CP) antenna for COMPASS navigation satellite system is presented. It works at B1(1.561098GHz) and B1–2(1.589742GHz) frequency band and it can also be used for global positioning system(GPS) at L1(1.57542GHz) frequency band. The radiating elements are two crossed bowtie dipole with rectangular gaps in the middle of the bowtie elements. A vacant-quarter printed ring is used to realize circularly polarized(CP) by and the gaps in the middle of the bowtie elements are designed to optimize CP and to produce resonances. The bowtie structure is used to widen the bandwidth. An inverted, rotary table, cavity-backed reflector is used to control the radiation pattern and acquire highly gain. The proposed antenna is fed by a single electricity port.

A ripple shaped and dielectric loaded water-drop antenna for ground penetrating radar

A innovative water-drop antenna with ripple shaped and dielectric loaded on the surface of the water-drop is presented for ground penetrating radar. The reflector plate is utilized behind the proposed antenna to enhance the radiation directivity. Finally, this design working at 400 MHz center frequency achieves 20% relative bandwidth approximately within S11<;-10dB and VSWR<;2. Likewise, the stable radiation pattern and higher gain more than 7 dB are obtained over the required frequency region. Also, the miniaturized structure is realized.