2,670 research outputs found
Dual-Band Electromagnetic Band Gap Structure for Noise Isolation in Mixed Signal SiP
No full textA compact dual-band electromagnetic band-gap (EBG) structure is proposed. It is shown through numerical simulation using 3D electromagnetic finite element modelling that by adding a slit to the classical mushroom shape an extra resonance is introduced and thus dual-band EBG structures can be built by cascading these new elements. It is also demonstrated that this novel approach can be used to isolate noise in a system such as a dual band transceiver integrated into a mixed signal system in a package. Finally, equivalent circuits have been established to aid the design process
Design and analysis of a novel compact high permittivity dielectric resonator antenna
No full textA very compact and efficient dielectric resonator antenna is proposed and investigated. The novel structure is analyzed using two numerical methods and design guidelines are established. Moreover, it is shown that—by using very high permittivity materials and appropriate design of the resonator and its feeding structure—wide frequency coverage is possible even at cellular frequencies. Simulation results are reported showing the effectiveness of the proposed antenna structure
Numerical investigation on compact multimode dielectric resonator antennas of very high permittivity
No full textTwo well known numerical techniques, the Finite Element Method (FEM) and the Finite Integration in Time Domain (FIT), have been applied to study a low volume high permittivity dielectric resonator antenna. The paper demonstrates that the design of a compact size and wide frequency coverage dielectric resonator antenna (DRA) for ISM band is possible by proper selection of the resonator shape in combination with appropriate resonant modes. Numerical results for one particular antenna design are reported
Analysis and suppression of SSN noise coupling between power/ground plane cavities through cutouts in multilayer packages and PCBs
No full textWe introduce a model of simultaneous switching noise (SSN) coupling between the power/ground plane cavities through cutouts in high-speed and high-density multilayer packages and printed circuit boards (PCBs). Usually, the cutouts are used in multilayer plane structures to isolate the SSN of noisy digital circuits from sensitive analog circuits or to provide multiple voltage levels. The noise-coupling model is expressed in terms of the transfer impedance. The. proposed modeling and analysis results are compared with measured data up to 10 GHz to demonstrate the validity of the model. It is demonstrated that the cutout is the major gate for SSN coupling between the plane cavities, and that substantial SSN coupling occurs between the plane cavities through the cutout at the resonant frequencies of the plane cavities. We also analyze and discuss the coupling mechanism and characteristics of the noise coupling, from which we evaluate a method of suppression of the SSN coupling. Proper positioning of the cutout and the devices at each plane cavity achieves significant noise suppression at certain resonant frequencies. The suggested suppression method of the SSN coupling was successfully proved by frequency domain measurement and time domain analysis
Characterization of high-frequency plane-to-plane coupling through cutout in multi-layer packages
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Reduction of cavity-to-cavity power/ground noise coupling through plane cutout in multi-layer PCBs
No full textSurface potential decay: effect of different corona charging times
No full textSurface potential decay measurement is a widely used tool to test the electrical properties of insulation materials. However, physical mechanism of the surface potential decay is still poorly understood. In this paper, the effect of corona charging time has been investigated. It has been found that as charging time gets longer initially the surface potential decays faster which is consistent with the existing observations. However, after the charging time reaches a certain length (changing with charging voltage), the surface potential decay becomes slower as the charging time increases. This type of behaviour has not been reported in literature. Further study on this phenomenon using the Pulsed Electro-acoustic (PEA) method which quantifies charge distribution and dynamics inside the sample validated the observation. Finally, the surface potential decay curves were analysed by fitting a double exponential decay equation and simulated by a bipolar charge transport model
Electromagnetic behaviour of flexible substrates with meshed and conductive films ground planes
No full textIn this work the electromagnetic performance at high frequency of flexible substrates with meshed and conductive film ground planes is compared with that of flexible substrates with unmeshed (solid) ground planes. Several types of specially designed structures have been studied - mesh ground, conductive film ground and solid copper ground. The conductive film used in this work is based on Tatsuta silver film which is developed especially for flex interconnects to be used in hinge applications in smart phones, and LCD drivers. The flat and bend cases of the flexible substrate are also compared and reported in this work. The comparison is done in frequency domain as well as in time domain through simulation. The structures are compared in terms of their far-field radiation as well as near-field coupling. The simulations have shown that the meshed and conductive film ground will affect the near-field coupling and the loss of the transmission structures but there is little difference in terms of radiating field
Design study of a high temperature superconducting generator with YBCO windings
No full textThis paper considers the merits of using a HTS rotor winding in a low-speed high-torque synchronous generator and the possibility of building a small-scale demonstrator to investigate the practicality of building such a machine. Pareto optimization results are presented for both full size and demonstrator size machines with YBCO rotor windings. This optimization used a variation of the Kriging method to reduce the number of FEM models required. A number of design issues and some sensitivity analysis are also discussed
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