Latest Articles
Intelligent Microwave Staring Correlated Imaging
Kui Ying Xinyu Yu Jiana Shen Shilu Zhang Yuanyue Guo
Microwave staring correlated imaging (MSCI) is a super-resolution imaging technique based on temporal-spatial stochastic radiation fields (TSSRFs), which requires an accurate calculation of the electromagnetic field at the imaging plane. However, systematic errors always exist in practice, such as the time synchronization and frequency synchronization errors of radar systems, which make it difficult to calculate the required TSSRFs accurately, and this deteriorates the imaging results. Meanwhile, some imaging algorithms have problems such as high computational complexity. In this paper, an intelligent MSCI method based on the deep neural network (DNN) is proposed, which can accomplish imaging directly from the echoes, avoiding the computation of TSSRFs. A multi-level residual convolutional neural network (MRCNN) is developed for the DNN, and simulations and experiments are carried out to obtain the dataset for training and testing the MRCNN. Compared with the conventional MSCI methods, the imaging results verify the effectiveness of intelligent MSCI in terms of imaging quality and computational efficiency.
Intelligent Microwave Staring Correlated Imaging
Efficient Computation of Sideband Power Losses in Pulse-Shifted Non-Uniform Time-Modulated Array with Arbitrary Element Pattern
Sujoy Mandal Sujit Kumar Mandal
This paper presents the mathematical formulation for the generalized closed-form expressions to calculate sideband power (PSR) of a nonuniform period time modulated array (NTMA) antenna with volumetric geometry by using pulse shifting strategy. For the arbitrary array geometry, the generalized expression of PSR is obtained by considering the universal omnidirectional element pattern in the form sinaθ|cosθ|b, a > -1, b > -1/2. Then, corresponding to different array structures such as linear, planar, and volumetric ones, the derived expression is simplified for different element patterns with possible combination of `a' and `b'. Through representative numerical results it is demonstrated that the obtained simplified expressions without hypergeometric function are useful to accurately calculate the amount of power losses due to sideband radiations with significantly less time than the conventional numerical integration (NI) method.
Efficient Computation of Sideband Power Losses in Pulse-shifted Non-uniform Time-modulated Array with Arbitrary Element Pattern
Numerical and Measurement Based Modeling of a MIM Capacitor in a 0.25 um SiGe -C BiCMOS Process
Huseyin Aniktar Huseyin Serif Savci
This study presents the generation of a scalable model based on measurement aided numerical calculations for MiMCap (Metal-Insulator-Metal Capacitor) structures with a 0.25 µm SiGe-C BiCMOS technology. Various MiM capacitor structures with several different area and peripheral sizes are fabricated in an in-house developed BiCMOS process. A set of fix-size models and a generic scalable model are developed based on numerical EM calculations. The validity of the constructed model is verified with the measurement results. The model includes the breakdown voltage ratings which are also extracted through the measurements. The model, EM simulations and measurement results are in good agreement.
Numerical and Measurement Based Modeling of a MIM Capacitor in a 0.25 um SiGe-C BiCMOS Process
A Miniaturized Ultra-Wideband MIMO Antenna Design with Dual-Band Notched Characteristics
Xuan Lu Shushu Linghu Furong Peng Ting Zhang
In this manuscript, a miniaturized Multi-Input Multi-Output (MIMO) antenna with dual-notch characteristics is designed for Ultra-Wideband (UWB) indoor positioning system. The proposed UWB MIMO antenna has a compact size of 35*35 mm2 with four orthogonally placed antenna elements on the print circuit board (PCB) with FR4. Each radiating element utilizes the combination of a rectangle and an irregular pentagon, and etches two inverted L-shaped slits to generate two notches in WLAN (5.00 GHz-5.82 GHz) and X-band (7.11 GHz-8.20 GHz). On the grounding planes, the rectangle grounding units are modified into L-shaped branches, on which stepped open-circuit slots and right-angled triangle truncations are etched to broaden the impedance bandwidth. Furthermore, three equidistant rectangular decoupling slits are etched to improve the isolation. The measured results are in good agreement with the simulated ones, which shows an impedance bandwidth of 116.68% (2.96-11.25 GHz) with isolation better than 17 dB. The antenna also has excellent characteristics of good radiation characteristics, total active reflection coefficient (TARC), diversity gain (DG>9.99), low envelope correlation coefficient (ECC<0.005) and channel capacity loss (CCL<0.4 bits/sec/Hz), which can be used in portable UWB-MIMO indoor positioning system.
A Miniaturized Ultra-wideband MIMO Antenna Design with Dual-band Notched Characteristics
PIER Letters
Design of a Planar Compact Dual-Band Bandpass Filter with Multiple Transmission Zeros Using a Stub-Loaded Structure
Guang Yong Wei Yun Xiu Wang Jie Liu Hai Ping Li
This paper presents a new compact dual-band bandpass filter (BPF) with a stub-loaded resonator structure that can independently change its operating band to support GSM and WiFi applications for modern wireless communications. A short-circuit stub with a metal through hole is placed into the symmetrical resonator together with a pair of step impedance stubs and a pair of uniform open-circuit stubs. Inside the resonator, the open stubs fold in on themselves, minimizing the circuit for integration with other parts and enhancing the selectivity of the filter. Even-odd mode theory can be employed to investigate the circuit because of the resonator geometric symmetry. The first and second operational frequency bands can then be built using the calculated odd and even mode frequencies to match our requirements. The manufactured experimental dual-band filter is compared to the simulation results, and the statistics revealed good agreement. The calculated structural measures 0.13λg × 0.1λg.
Design of a Planar Compact Dual-band Bandpass Filter with Multiple Transmission Zeros Using a Stub-loaded Structure