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A procedure is presented to retrieve motion parameters of the moving target from single-channel synthetic aperture radar (SAR) data in a long-time coherent integration, and make motion compensation for SAR imaging. Firstly, the slant-range velocity is estimated using Radon transform which is not affected by the Doppler ambiguity, and after correcting the range walk induced by the slant-range motion,...
In this paper, an efficient approach, named unitary matrix pencil method, is presented for pattern synthesis of sparse linear arrays. An equivalent real-valued matrix pencil can be achieved to determine the relation between element positions and new generalized eigenvalues through using the unitary transformation for the Hankel matrix with the sampled pattern data. The proposed method increases up...
An adaptive nulling scheme for a time-modulated array (TMA) based on Linearly Constrained Eigencanceler (LCEC) beamforming is introduced and investigated. Compared to conventional phased arrays, a TMA is potentially simpler to realize in hardware because it does not require a complex feed structure or phase shifters. LCEC is used in various application of array signal processing. And in this contribution...
A controlling circuit for varactor diodes based on K-band substrate integrated waveguide (SIW) leaky-wave antenna is presented in this paper to accomplish pattern reconfiguration. The varactors' DC bias is supplied by a sawtooth wave generated from the FPGA which allows automatic and continuous variation of the capacitance of the varactors. An isolating circuit between DC voltage and RF is applied...
Iterative solution of the electric-field integral-equation (EFIE) faces redundant computations for the multiple right-hand-side (RHS) problems. An efficient direct solver of the EFIE based on hierarchically compressed matrix algorithm is developed to deal with multiple RHSs. The multilevel UV method is employed to construct a hierarchically compressed matrix. Exploiting the symmetry of EFIE system...
When the multilevel fast multipole algorithm (MLFMA) is adopted to accelerate the solution of matrix equation generating by the volume-surface integral equation (VSIE), different submatrix-selecting schemes of near-field matrix preparing for constructing sparse approximate inverse (SAI) preconditioner are discussed. Numerical result indicates that for VSIE, a SAI preconditioner with high quality can...
This paper presents a set of compact microstrip filters and diplexers based on the subwavelength metamaterial unit. Such metamaterial unit is developed from the classic split ring resonator by extending and bending the wire and shorting one of the end to ground. Firstly, the microstrip filter consisting of two metamaterial units and the diplexer based on the obtained filter are demonstrated experimentally...
Large APAA (active phased array antenna) contains hundreds of elements and the performance of an APAA will degrade over time as a result of changes mainly in the solid-state components. For airborne and satellite-borne APAA applications, ground-based calibration sources may be difficult or impractical to implement due to the constraints of volume and resources. In this paper, a novel self-calibration...
In this paper, a fourth-order V-band substrate integrated waveguide (SIW) filter is presented. The design of this filter is based on high-order mode coupling. By adding two different over mode cavity coupling, two transmission zeros are generated at both side of the passband to get better out-of-band suppression. As demonstrations, the filter was processed using a RT / Duroid 5880 dielectric plate...
Infrared stealth is increasingly important in modern war, for active infrared detection the stealth material should perform high absorption. An infrared absorber which consists of a metal ground plane, a dielectric slab and resistance patches is designed based on the resistance frequency selective surface (RFSS). The absorption of the absorber is investigated by the CST Microwave Studio and the simulation...
In this paper, a set of higher-order hierarchical divergence-conforming vector basis functions based on curved triangular patches is presented for EM scattering analysis of PEC objects above a lossy half space. Numerical examples are presented to demonstrate the valid and efficiency of the proposed approach.
In this paper, the modeling and simulation of the electromagnetic environment of shipboard equipment is studied. The electromagnetic environment simulation of the ship is carried out on the basis of establishing the sea surface and the ship model and under the different electromagnetic physical quantity. Sea and ship models will be drawn by CAD software, obtaining the electromagnetic simulation results...
A novel composite rough surface model is presented for describing island in deep sea. Monte Carlo method is used to generate composite rough surface. Gauss spectral function is used to simulate actual ground surface of island. Pierson-Moskowitz (PM) spectral function is used to simulate actual sea surface of deep sea. Based on the theory of composite rough surface modeling, weighted inverse tangent...
A dual-band horn antenna operating at 94 GHz and 340 GHz is presented in this paper. The proposed structure consists of a corrugated conical horn and a tapered dielectric strip. The conical horn is responsible for 94 GHz, and is excited by vertical TE10 mode. The dielectric strip is inserted in the horn, which is responsible for 340 GHz, and is excited by horizontal LSM mode. Both of the two bands...
A 28 GHz, planar, electrically small Huygens source antenna is presented. The proposed antenna is composed of electric Egyptian axe dipole (EAD) and magnetic capacitively loaded loop (CLL) near-field resonant parasitic (NFRP) elements with a coax-fed dipole radiator. It has broadside radiating and planar performance characteristics. To confirm its efficacy for on-body applications, the specific absorption...
This paper presents a novel miniaturezation Quasi Yagi-Uda antenna based capacitive loading technique and new layout. In the proposed antenna, the horizontal size of the proposed antenna is reduced by adding vertical metallic strips at the end of the driver and reflector. Meanwhile, the 1/4 wavelength transformer and balun are placed horizontally to reduce the vertical size. In this way, the overall...
We present a slot antenna with the footprint size of 4 × 4 cm2 (0.12λ × 0.12λ at 915 MHz) for wearable passive UHF RFID tags. In addition to the main radiating slot, cuts made into the surrounding conductor increase the antenna radiation efficiency and help to self-match the antenna impedance with the RFID microchip in the body-worn configuration. Antenna structure is uniplanar and optimised for a...
This paper presents a compact SIW (substrate integrated waveguide) 3×3 Butler matrix (BM) for 5G mobile applications. The detailed structuring procedures, parameter determinations of each involved component are provided. To validate the 3×3 BM, a slot array is designed. The cascading simulations and prototype measurements are also carried out. The overall performance and dimension show that it can...
This paper proposes a convenient approach to control the electromagnetic waves inside horn antennas to improve their radiation performance by placing a metasurface lens inside the horn. The lens consists of two identical metallic dipole arrays printed on both sides of a single dielectric layer. Through full-wave electromagnetic simulations, a comparative study of the enhanced radiation properties...
This letter presents a novel medium-insensitive and dual-polarized chipless RFID tag antenna. The tag consists of nested concentric coplanar square loops, and adjacent loops are connected by two stub lines at the center of the opposite sides, respectively. The structure is designed to obtain the following function relationship between the loop number n and resonant mode number N: N=2(n-1). The proposed...
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