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A planar microstrip-fed two-arm spiral antenna has been designed for achieving wideband circularly polarized bandwidth in this paper. Compared with conventional spiral antennas, a simple feeding line is employed to feed the antenna. The planar structure can be printed using a single layer substrate without an external balun. In addition, the arc-shaped cut is embedded in the ground plane and a tapered...
A broadband right-handed circularly polarized (RHCP) global navigation satellite system (GNSS) antenna is proposed to cover global positioning system (GPS), GLONASS, Galileo and Compass applications. The −10 dB reflection coefficient bandwidth is fully covered all of the GNSS bands. The 3-dB axial ratio (AR) bandwidth is 475 MHz from 1.175 to 1.65 GHz. The gain is above 0 dBi from 1.22 to 1.65 GHz...
An efficient hybrid method of SJMCFIE combined single integral equation with the electric/magnetic current combined field integral equation is used for analysing scattering from composite conductor and multiple dielectric objects, in which, SIE can reduce one half unknowns in dielectric regions. SJMCFIE can greatly reduce the storage requirement. Moreover, Multilevel Fast Multipole Algorithm is employed...
This paper analyzed the precision loss problem in calculation of EM wave propagating in extreme plasma environment. To overcome the problem, a numerical calculation with arbitrary precision is proposed. The simulation results show the effect of computational precision loss on EM wave propagation and also illustrate the validity of the arbitrary-precision calculation method.
An IR-UWB indoor positioning is proposed in the paper that combines the algorithm of Time-of-Arrival (TOA) and band-gap modulations. The positioning is referenced by three UWB locators that have different band-gap and deployed in a right triangle. An object can determine its position by identifying pulse backscattered on locators and each locator's signatures through recognizing the exact segment...
In this paper, a reconfigurable frequency selective surface (FSS) using varactor diodes is presented for low RCS radome application. The FSS is composed of three-layered metallic structures. The varactors are biased with a middle layer bias wire connected to via holes and wire grids on front layer. The back layer is a wideband bandstop structure for out-of-band RCS reduction. The FSS radome without...
In this paper, we present a multifunctional active frequency selective surface (MAFSS), which consists of two metallic layers and a substrate layer. Three electromagnetic functions of switching, polarization selection and frequency tuning, are integrated into a single board. The bias networks are embedded in each layer and comprise the MAFSS elements themselves, which eliminates the need of extra...
In this paper, a statistical research is carried on the radar cross section reduction (RCSR) performance of diffuse metasurface composed of two-layer stacked-patch elements. The research focuses on the broadband RCSR behavior of the metasurface in specular direction. An advanced uniform random distribution of reflection phase is proposed for the diffuse metasurface to improve the broadband RCSR performance...
In this paper, a Volterra series nonlinear equalization (NLE) scheme is proposed to compensate the nonlinear distortions in vector mm-wave system over fiber link. The principle of NLE scheme is presented. The performance of NLE scheme is investigated through a 5Gbaud 16QAM over 40GHz RF carrier simulation system. The proposed NLE scheme is proved to be feasible in nonlinearity mitigation in vector...
Transient voltage suppressor (TVS) device is the chief way by which the susceptibility to Electromagnetic pulse (EMP) of equipment can be decrease. Prior to each application, the TVS device has to be tested in order to evaluate its performances. In this paper, a new EMP protection performance testing system is designed and the Suppressing characteristics of four kinds of TVS device during EMP stressing,...
In this paper, we propose a new design of a dual-polarization near-field focused reflective metasurface for wireless power transfer. The reflective metasurface is composed of printed cross-dipole elements with different arm lengths, which is aimed to independently generate focused point with dual-polarization. Numerical simulations demonstrate that the proposed reflective metasurface can focus the...
We analyze the influences of non-Kolmogorov turbulence and source parameters on beam wander of Bessel-Gaussian (BG) beams in the atmosphere. BG vortex beams with larger topological charge and beam parameter η can better mitigate the turbulence effects on beam wander than BG non-vortex beams. Both inner- and outer-scale effects on beam wander should be considered when BG beam goes through atmosphere...
The nonlinear response of silver nanoparticles filled epoxy resin composites under increasing applied voltage is investigated. The influence factors of applied high voltage on the conductivity of composites are measured by the collection of the electric current passing through the sample. With the increase of applied voltage, the composite has a nonlinear conductive characteristic. The contributing...
This paper presents analytical expressions and equivalent circuits for calculation of EMP responses (voltages or currents) on transmission lines. The analytical expressions are based on BLT equations, and equivalent circuits are based on telegraph equations and the controlled sources. Both methods are testified by experiments, and comparison of the two methods is discussed.
Recently, a point-by-point active millimeter wave imaging system with shortened imaging time and reduced system cost and complexity is proposed. Demand for a mask to shape transceiver beam arises accordingly. Absorbing materials plays a critical role for the mask. Design of thin multilayer planar absorber in this paper. Differential evolution (DE) algorithm is implemented to solve the equivalent multi-dimensional...
Pursuing higher speed of digital signal processing is the non-stop goal for human. When digital filter has been chosen, how to upgrade the speed of filter signal processing is a challenge for software engineer. This paper analyzes the techniques of sliding window and pipeline, and illustrates the application with two order Butterworth filter as an example. These techniques can condense the signal...
An ultra-wideband metasurface is designed for suppressing the specular electromagnetic wave reflection or backward radar cross section (RCS). Square ring structure is chosen as the basic meta-atoms. A new physical mechanism based on size adjustment of the basic meta-atoms is proposed for ultrawideband manipulation of electromagnetic (EM) waves. Based on hybrid array pattern synthesis (APS) and particle...
A novel broadband circularly-polarized (CP) antenna fed by strip-line is proposed. The CP operation is achieved by corners truncated and can be significantly improved by introducing a pair of half loop strips around two opposite corners of the square patch. The bandwidths for the axial ratio (AR < 3 dB) and relative impedance (|S11| < −10 dB) is 7.6% (16–17.2 GHz). The proposed antenna also...
Two topology optimization methods, namely material distribution and level-set methods, are used for optimization of microstrip antennas. By successive application of the two methods, the optimization process can take advantage of the powerful topology-searching ability of the material distribution method and the feature of generating structures with smooth and low-sensitivity boundaries of level-set...
Localized surface plasmon resonances (LSPR) give rise to enhanced fields near the interface between the metallic and dielectric boundary. Strong excitation intensities can lead to the formation of photothermal bubbles around plasmonic nanoparticles. Numerical simulation is indispensable in predicting and analyzing plasmonic bubble as the measurement is always too expensive or too complicated to be...
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