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In this paper, a novel method using conformal technique of finite-difference method (FDM) is proposed to solve the distributed capacitance for microstrip lines. Instead of deriving the average dielectric constant ε, this method uses electric field numerical weights to process the inhomogeneous cells, and takes the discontinuous effects of both inhomogeneous Ampere cell and Faraday cell into account...
In this work, a hemispheric radome with conformal frequency selective surface is designed and analyzed by using the physical optics method. The conformal frequency selective surface consists of two layers of substrate and three layers of periodic patches and grids. The radome is manufactured and measured. The comparison between the analysis result of the physical optics method and the experimental...
In the aperture synthetic radiometer system, the calibration of phase error plays an important role in improving the image quality. Errors of both antenna and receiving channel will cause aperture synthetic phase error in each sub-aperture, so arouse deterioration in image quality. An in-orbit external calibration method for aperture synthetic radiometer using external calibration sources on ground...
The sheath flows surrounding a near-space blunt-cone vehicle at different speeds are simulated with FLUENT software. Analysis on the flow fields shows that, when the vehicle speed exceeds a certain threshold, the relationship between concentration and speed is opposite to that in low-speed state. Then, the Runge-Kutta method is applied to solve the EM ray equation in the inhomogeneous plasma sheath,...
As one special type of atmospheric refraction, duct can make VHF-band radio waves and above form transhorizon propagation, playing an important role in communication and radar detection. So it is necessary to study the characteristics and contributing factors of duct. Based on the sounding data in Qingdao during 2005–2013, the signatures of duct, temperature inversion and intense humidity gradient...
In urban mass transit railway system, the leaky rectangular waveguide is continuously mounted along the track, for both under- and on-ground environments, to realize a reliable wireless communication between trains and ground. The performance of the waveguide on ground is easily affected by the bad weather, especially for the heavy snowing weather. The available works only considered the effect of...
This work presents a study of a PIN tuned active phase gradient metasurface to be used for beam-steering application. The unit cell of the active metasurface consists of square-loop slot loaded with PIN diodes. The phase difference between the unit cells of the metasurface is generated by different position of the PIN diodes welded in the unit cell. And the refractive beam angle of the metasurface...
It is found that the path adjustment factor or the rainfall adjustment factor achieved from most of model is greater than 1 in short path by analyzing the prediction model of rain attenuation currently available in terrestrial links. It is inconsistent with the assumption that the shorter the propagation path length is, the more uniformly distributed spatially and temporally the rainfall rate is....
This paper proposes a method to steer the beam of antenna array by loaded dielectric lens. The particular application demands the array has maximum gain and distinct beam point but the traditional methods are unallowable, such as phaser. Consequently, Dielectric lens loading is put forward to realize the demand. The effect of parameters of the dielectric lens is studied firstly. Then, the paper researches...
A new multi-sleeve monopole antenna for APP-terminal communication is proposed and compared with the conventional sleeve monopole antenna. The prototype of the proposed antenna is constructed and simulated, which shows that the proposed antenna features excellent radiation characteristics against the working frequency, where the voltage standing wave ratio (VSWR) is less than 1.5.
A novel broad beamwidth leaky-wave antenna (LWA) array with non-uniform transverse slots etched on substrate integrated waveguide (SIW) is proposed. A four-way SIW power divider with equal outputs of phase and amplitude is designed to feed four SIW LWAs with different periodic tapered slots. All these LWAs are working on the 𢀒1th spatial harmonic radiation mode, and by choosing periods of slots properly,...
This paper introduces the design method of a dual band microstrip patch antenna, from the most basic of microstrip patch method using bilateral radiation, a dual band microstrip antenna is designed, simulated using HFSS software, results show that, choose a 50 ohm coaxial cable feed position to make the antenna work at the center frequency respectively in 9.96GHz 12.84GHz. And in the 9.96GHz and 12...
A high-gain and low-profile lens antenna is designed using phase-gradient metasurface (PGMS). The PGMS is a planar structure and is composed of many PGMS units. By changing the size of the metal patch on the unit gradually, we can obtain a transmission phase-shifting range of about 360 degrees. Based on the principle of the phase compensation of the optical lens, the PGMS is designed. Since this phase-gradient...
This paper presents a wideband antenna consisting of two series-fed fan-shaped bowtie dipole antenna elements and an integrated tapered balun for through-the-wall imaging radar (TWIR) applications. The two fan-shaped bowtie dipole antenna elements with different radii and same flare angle are connected using a coplanar stripline and backed by a ground reflector. The balun realized by a tapered microstrip...
In this work, we propose a high-gain planar antenna based on the phase gradient metasurface whose super cell is composed of six different H-shaped elements. The metasurface can not only couple the y-polarized incident wave into spoof surface plasmon polariton but also achieve the reverse process when the splitter feed provides appropriate field and wave vector. The antenna works well that the return...
The rapid development of modern wireless communication system has greatly promoted the development of the reconfigurable filters. This paper presents a hexagonal structure reconfigurable filter which operates at five different frequencies. The resonant characteristics of stepped impedance resonator (SIR) is utilized by equaling the transmission line of low impedance to multiple parallel lines of high...
Based on the appearance of plasmasphere when ballistic missile enters in reentry phase at the speed of supersonic, impacts of reentry plasma parameter on the real RCS value of warhead are studied. According to the calculating method of dynamic RCS time series, the model is established to simulate electromagnetic scattering of reentry ballistic missile. By simplifying the trajectory reasonably, the...
This letter presents a field expansion of the solution to three-dimensional electromagnetic scattering problems of a uniaxial anisotropic spheroidal particle illuminated by an off-axis Hermite-Gaussian (HG) beam. Using the complex-source-point method, and the relationship between spherical and spheroidal vector wave functions (VWFs), a method is put forward to expand the incident Hermite-Gaussian...
This paper presents a ultra-broadband loaded monopole antenna. To broaden the operation bandwidth of the monopole antenna and efficiently resolve the problem of the nulls of the antenna pattern, a novel antenna design method is proposed by loading with lumped elements. The loads are parallel resistor/inductor (RL) circuits. The loaded antenna having a larger bandwidth, with the maximum gain is almost...
An antenna with both solid dielectric and liquid materials is designed and analyzed. The influence of the thickness and parameters of the substrate is investigated. The performance of different liquid materials including sea water, oil and distilled water is analyzed. The influence of the distribution of the liquid and other relevant factors are studied. The simulation results revealed the validity...
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