A Laguerre-based finite-difference time-domain (FDTD) method for two dimensional anisotropic dispersive materials is proposed in this paper. Taking advantage of the property of Laguerre polynomials, the nth derivative of field components in Laguerre domain is deduced. The four elements of the tensor permittivity of the 2-D anisotropic dispersive media can be unified into a general form in frequency domain. Then the general relationship between electric fields and electric flux densities can be derived in Laguerre domain. Using spatial interpolation of transition and central difference scheme, the formulations are obtained. Two examples of wave propagation in anisotropic magnetized plasma are used to validate the efficiency of the proposed method.
A new simple interface circuit for quartz vibrating gyroscope (QVG) driven by sine-wave is presented in this paper. The interface circuit is composed of self-excited loop of driving circuit and detecting circuit. A new multiplier is designed to achieve the controlling to drive signal. The usage of new multiplier realizes the nonlinear adjustment to the amplitude of feedback drive signal. Consequently, the requirement of rapid oscillation, low harmonic and high stability is also achieved. The interface circuit is fabricated in a 0.5 µm CMOS process and the test results show that the start time of drive signal is less than 2 ms. The drive signal frequency stability can reach to 0.084% (1-sigma) and the harmonic distortion is about 1.056%. The output noise of Quartz Vibrating Gyroscope is 0.00023°/s/√Hz at 3 Hz and nonlinearity is about 107 ppm. The bandwidth is more than 60 Hz. Meanwhile, the short stability (1-sigma) is 2.1°/hr, the angular random walk (ARW) and bias drift are 0.01388°/√hr and 0.16°/hr respectively.
Histograms of Oriented Gradients (HOG) descriptor significantly outperforms other features for object detection, especially for pedestrian detection. Exploitation of high performance and efficient HOG IP has been a research hotspot in Automotive Electronic. In this letter, a CORDIC-based Parameters-fusion LUT HOG algorithm is proposed and made as the hardware IP (Intelligent Property). To decrease the computational effort and improve the accuracy, pipeline Coordinate Rotation Digital Computer (CORDIC) is applied to generate the magnitude and orientation of gradient. Parameters- fusion Look-Up-Table (LUT) based regional division can operate the tri-linear interpolation in HOG with high speed. Circuit design and chip fabrication were performed using 0.18 µm CMOS technology. Measurement result shows that this CORDIC-based Parameters-fusion LUT HOG IP reduces the hardware overloads and can be used as the general IP for extracting features.
Perovskite Ba0.5Sr0.5TiO3 (BST) thin films with a thickness of 300 nm are deposited on high resistivity silicon through pulsed laser deposition. The permittivity of BST is changed by applying an external electrostatic field. Coplanar waveguides (CPWs) are designed to extract the field-dependent permittivity of the film in the frequency range from 1 GHz to 110 GHz. A Subregional Match 3-Dimensional finite element method (SM 3D FEM) is proposed to implement the permittivity extraction. We analysis the electric field distribution in BST film, and thus divide the BST film in a reasonable way in order to achieve the permittivity of each small region in BST film by S-parameters-phase matching. The relative difference between measured and simulated S-parameters-phase is defined to describe the precision of the result. Experimental results show that the relative difference is less than 1.3%. We also found that the permittivity tunability is almost unchanged in a wide frequency domain, the variation of the tunability less than 0.16. The relative dielectric permittivity ξBST at 0 V equals 1148.9 at 1 GHz and reduces to 311.7 at 110 GHz, and ξBST at 100 GHz equals 315.8 at 0 V and declines to 193.4 at 30 V. The tunability of BST film is about 38.7% at 100 GHz.
A novel design of a customizable triple-band EBG (Electromagnetic Bandgap) bandpass filter is proposed. The EBG filter is manufactured by a conventional 2-layer PCB process in RO4350 substrate with surface mounted lumped capacitors. Specific working frequency of each band of the filter can be selected on demand by adjusting the value of corresponding capacitors, while the filter’s performance and compact design is not compromised. The experimental results show a filter with size of 28.00 × 28.00 × 1.52 mm3 in PCB achieving performance of insertion loss of 2.57 dB, 2.82 dB; return loss of 13.35 dB, 28.09 dB at two passbands with center frequencies of 2.33 GHz, 4.23 GHz respectively. Good agreement was obtained where the filter exhibited the third passband with center frequency of 1.87 GHz. The filter has band to band isolation better than 36.0 dB.
Sharing common subexpressions (CSs) in the logic expressions can reduce the total gates in hardware implementations of parallel Chien search. In this paper, we prove that sharing CSs will increase the delays of the hardware implementation. Based on the proof, a shortest-path-keep common subexpression elimination (SPK-CSE) algorithm is proposed. By using SPK-CSE algorithm, the output delays can be kept unchanged after sharing CSs. The parallel Chien search implemented with the proposed SPK-CSE algorithm can achieve the minimal delay.
A multifunction circuit to simplify a multiband front-end operating at very different bands is proposed. The multifunction circuit operates as a sub-harmonic mixer or an attenuator depending on a control voltage. A multiband front-end using the proposed multifunction circuit can reduce component, is 23 percent smaller, and is less expensive compared to a conventional architecture with a switching circuit.