The mismatch of in-phase and quadrature channels in quadrature receiver affects and constrains radar detection performance in coherent radar. It is necessary to keep the in-phase and quadrature branches symmetrical. I...The mismatch of in-phase and quadrature channels in quadrature receiver affects and constrains radar detection performance in coherent radar. It is necessary to keep the in-phase and quadrature branches symmetrical. In this letter, an adaptive method to detect imbalance parameters is derived by means of evaluating channel errors from the received signal sequences.No matter how the bias degree of the gain and phase errors in I/Q channels are, the proposed adaptive scheme can obtain good calibration results. And the required calculations are only a few multiplications and additions. No need of a special test signal, the introduced method is simple to implement and easy to operate.展开更多
In this article,a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system.Two sets of Helmholtz coil pairs with a V-shap...In this article,a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system.Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil.The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation.The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM).Good magnetic resonance (MR) images are achieved on a shepherd dog.展开更多
Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch i...Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch is developed as a surveillance system for old people;we chose to equip it with a wireless charging system for greater ease of use, imperceptible in the everyday life and waterproofing. This paper presents the development of a printed receiver coil to be integrated in a wireless charger to be used in an elderly tracking patch. The proposed design is validated using simulation that presents a good agreement with measurement results: Simulation (@150 KHz: L = 10.74 μH;R = 3 Ω) and Measurement (@150 KHz: L = 10.8 μH;R = 3.16 Ω). The receiver coil is elaborated on a polyimide substrate in the cleanroom of our laboratory LAAS-CNRS (Laboratory for Analysis and Architecture of Systems-National Center for Scientific Research) and a PCB (Printed Circuit Board) charger prototype is fabricated to test its performances before the integration of the wireless charging property in the tracking patch. The proposed coil presents a good compromise between small size and efficiency. For a charging current of 7.5 mA, this coil can ensure the recharging of the patch up to a distance of 4.8 mm between the Qi transmitter and receiver which is more than enough for our application.展开更多
文摘The mismatch of in-phase and quadrature channels in quadrature receiver affects and constrains radar detection performance in coherent radar. It is necessary to keep the in-phase and quadrature branches symmetrical. In this letter, an adaptive method to detect imbalance parameters is derived by means of evaluating channel errors from the received signal sequences.No matter how the bias degree of the gain and phase errors in I/Q channels are, the proposed adaptive scheme can obtain good calibration results. And the required calculations are only a few multiplications and additions. No need of a special test signal, the introduced method is simple to implement and easy to operate.
基金supported by the National Key Technology Research and Development Program of China (Grant No. 001BA210A03)
文摘In this article,a novel designed radio frequency (RF) coil is designed and built for the imaging of puppies in a V-shape permanent magnetic resonance imaging (MRI) system.Two sets of Helmholtz coil pairs with a V-shape structure are used to improve the holding of an animal in the coil.The homogeneity and the sensitivity of the RF field in the coil are analysed by theoretical calculation.The size and the shape of the new coil are optimized and validated by simulation through using the finite element method (FEM).Good magnetic resonance (MR) images are achieved on a shepherd dog.
文摘Monitoring systems for elderly require a compromise between reduced size and operational autonomy. The latter to get a system as independent as possible and to fit with our application needs for daily use. Our patch is developed as a surveillance system for old people;we chose to equip it with a wireless charging system for greater ease of use, imperceptible in the everyday life and waterproofing. This paper presents the development of a printed receiver coil to be integrated in a wireless charger to be used in an elderly tracking patch. The proposed design is validated using simulation that presents a good agreement with measurement results: Simulation (@150 KHz: L = 10.74 μH;R = 3 Ω) and Measurement (@150 KHz: L = 10.8 μH;R = 3.16 Ω). The receiver coil is elaborated on a polyimide substrate in the cleanroom of our laboratory LAAS-CNRS (Laboratory for Analysis and Architecture of Systems-National Center for Scientific Research) and a PCB (Printed Circuit Board) charger prototype is fabricated to test its performances before the integration of the wireless charging property in the tracking patch. The proposed coil presents a good compromise between small size and efficiency. For a charging current of 7.5 mA, this coil can ensure the recharging of the patch up to a distance of 4.8 mm between the Qi transmitter and receiver which is more than enough for our application.
