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As to digital arrays, amplitude-phase inconsistency between channels has a great influence on the performance of the adaptive antenna. With regard to the imbalance of chirp signal caused by the mismatch of channels, this paper studies the characteristics of the chirp signal and adaptive filter, and proposes a method based on the LMS adaptive filtering algorithm to eliminate the amplitude-phase inconsistency...
The dyadic Greens' functions of the magnetic vector-potential A (DGFA) for unbounded uniaxial anisotropic media are considered in this paper. It is at first derived in the spectral domain through eigenvalue decomposition method, and later transformed back to the spatial domain to get triple integral forms, which are finally simplified to Sommerfeld integrals. In order to verify these mathematical...
In this paper, we applied the Born Iterative Method (BIM) to reconstruct three-dimensional inhomogeneous objects buried in spherically multilayered media. The nonlinear inverse problem is linearized by Born approximations and solved iteratively via the conjugate-gradient approach (CG). The forward scattering problem in the spherically multilayered media is solved by stabilized biconjugate-gradient...
An active MIMO system at 360 GHz as a part of the EU FP7 project TeraSCREEN is presented. A combination of geometric focusing in elevation and MIMO based digital beam forming in azimuth will provide real-time 3D images. The MIMO system consists of 16 transmitter and 16 receiver antennas within one single array. This configuration represents a linear array of 256 virtual antennas. This set-up allows...
This paper investigates the capabilities of Neural Network (NN) application in estimating the missing ionospheric total electron content (TEC) data via interpolation and extrapolation methods. TEC is an important parameter that describes the state of the ionosphere. A multilayer feed-forward network with a back propagation algorithm is applied to estimate the TEC over Parit Raja (Lat. 1°52′N, Long...
We report parallel solutions of inverse multiple scattering problems with the Born iterative method (BIM) and the distorted Born iterative method (DBIM). The large computational costs of the Born solvers are reduced using the multilevel fast multipole algorithm (MLFMA). Furthermore, the solutions are obtained on supercomputing environments via parallelization of the Born solvers. This is achieved...
To evaluate the possibility of information leakage by observing the electromagnetic disturbance radiated from VGA and DVI graphical interface, we propose an evaluation method by using a FSET 22 receiver. IT devices used for classified information display have to minimize the risk of electromagnetic eavesdropping. In those devices the aim is to minimize the level of radiated emissions via radio path,...
Interest in Passive Radar has grown significantly over the last decade. However, most Passive Radar systems have been experimental set-ups tailored to a signal frequency band or a single illuminator. In this paper, the design considerations and the resulting Multiband Bistatic Passive Radar (MBPR) structure are described and the evaluations of various measurement campaigns with multioctaves array...
A unique wide band receiver for radio astronomy has been designed and constructed. Receivers used for radio astronomy consist of two parts, the front end cold electronics and the back end warm electronics. While the cold electronics provides for a low noise amplifier and receiver calibrations, the warm electronics provides analog signal processing that shapes and filters the signals before digitizing...
In this paper, a double V-chirp waveform scheme is employed to suppress the false targets present in the delay-Doppler maps, which are caused by the use of traditional V-chirp transmitted signal in multiple targets environment. Then a family of nonlinear processing methods are applied and the delay-Doppler resolutions of these two waveform schemes are also compared, proving that the proposed waveform...
In free-space optical communication, aperture averaging effect can be used to optimize receiver design. A variety of factors contribute to aperture averaging effect, such as the receiving aperture, the light source, and the turbulence link. Cassegrain system is usually used as the receiver. It is technically feasible to optimally design the light source according to Cassegrain system's aperture averaging...
The signal coherent fusion of multiple radars combined with multiple pulses coherent integration can effectively improve the detection performance and recognition ability in the low signal to noise ratio (SNR) environment. Furthermore, the widely distributed sensors can use the target spatial diversity and against slow fluctuations of the target radar cross section (RCS). The difficulty of the signal...
Frequency diverse array (FDA) radar has attracted a lot of attention recently owing to its unique beam pattern and potential ability of completing multiple tasks simultaneously. Generally, FDA radar employs a small frequency offset across the transmit elements of the array in order to generate the range-angle-time-dependent beam pattern. With respect to the receiver architecture for FDA radar, there...
The main goal of this research is to design, fabricate, and test deployable VHF antennas for 6U Cubesat platforms to enable validation of root zone soil moisture (RZSM) estimation algorithms for signal of opportunity (SoOp) remote sensing over the 240–270MHz frequency band. The proposed work provides a strong foundation for establishing a technology development path for maturing a truly global direct...
We report on the experimental demonstration of an FMCW radar operating in the 25.7–26.6 GHz range with a repetition rate of 500 sweeps per second. The radar is able to track the breathing rate of an adult human from a distance of 1 meter. The experiments have utilized a 50 second recording window to accurately track the breathing rate. The radar utilizes a saw tooth modulation format and a low latency...
Terahertz (THz) communications, which use carrier frequencies from 100 GHz to 1 THz, have been attracting great interest for ultra-broadband wireless links [1]. Potential applications cover wireless local area networks, wireless personal area networks, near-field communications such as kiosk downloading, wireless connections in data centers, device-to-device communications, wireless backhauling, etc...
“Successive Estimation Technique” is introduced to microwave tomography in a concrete diagnosis. With the technique, the concrete body is marked off into reconstructable and un-reconstructable zones automatically in the reconstruction, and clear tomography image is obtained even in a noise contamination case.
Forecasting and nowcasting of severe weather conditions, such as tornadoes, local heavy rainfall, thunderstorms, and hailstorms, are important subjects in meteorology. Cumulonimbi such as supercells and multicell convective storms locally cause these natural hazards in a short period of time. To mitigate their damage, technology to detect a “sign” prior to the event should be developed. One of the...
In multistatic radar systems, range measurements are widely used for target localization. Due to the unknown system delay, the range measurements are usually not accurate. Combining the range measurements with great errors for target localization can cause a significant localization error. In this paper, an algorithm is proposed tore move the range measurements with significant errors for better localization...
The 2012 World Radiocommunication Conference (WRC-12) allocated the 694– 790MHz (700 MHz) band for the mobile service on a co-primary basis with other services including digital terrestrial television service in Region 1. Countries of Region 1 will also be able to continue the use of these frequencies for their digital terrestrial television services. This allocation of mobile service in Region 1...
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