A novel high gain two port planar antenna for 5G millimetre-wave and satellite band is presented. The proposed antenna besides working in the millimetre-wave range has an added feature to work for the satellite X-band as well. The antenna has a miniaturised low-cost planar geometry having the dimensions of 1.83λ x 1.83λ x 0.07λ at 27.5 GHz, designed and fabricated on a Rogers RT/duroid substrate of thickness 0.8 mm. The proposed antenna has return loss values of 12.34 dB and 17.94 dB for the two resonant millimetre wave frequencies of 27.24 GHz and 28.88 GHz respectively and 12.66 dB for the satellite band frequency of 8.42 GHz. The antenna attains a peak gain of 10.2 dBi for 28 GHz millimetre wave band and 6.2 dBi for satellite X-band by exploiting an inverse micro-strip Yagi director geometry. The isolation between two ports has been found satisfactory thus making it operate efficiently forthe available Ka and X band capacity of the Wideband Global Satcom system (WGS). The experimental results regarding the fabricated prototype are presented and compared with the simulated results, which are in good agreement. The performance of proposed antenna regarding radiation efficiency, directivity, gain, radiation pattern, and good isolation between the two ports makes the antenna employed as a suitable candidate for satellite communication and especially for 5G millimetre-wave communication.....

A compact 30×30 mm² high performance four elements ultra-wide band multi-input multi-output (UWB MIMO) diversity antenna is proposed. The prototype antenna consists of four symmetrical antenna elements which are orthogonally placed on top surface of the substrate with partial slotted ground plane. The isolationamong the antenna elements is improved by placing antenna elements orthogonally without any additional decoupling structure. The various antenna characteristic parameters, i.e. return loss (< -10 dB), isolation parameter (<-22 dB), radiation patterns near omnidirectional, and maximum realized gain 4.8 dB, were measured. The MIMO performances of prototype antenna were also measured in terms of various MIMO diversity parameters and found ECC<0.06, DG>9.98 dB, TARC<-10 dB and MEG<-3 dB throughout the frequency band. This design provides an operational bandwidth from 2.15 to 16.75 GHz which covers the whole UWB spectrum and is suitable for portable devices.....

A new local method for magnetic resonance electrical properties tomography (EPT), dubbed transverse-EPT (T-EPT), is introduced. This approach iteratively optimizes the dielectric properties (conductivity and permittivity) and the z-component of the electric field strength, exploiting the locally E-polarized field structure typically present in the midplane of a birdcage radiofrequency (RF) coil. In contrast to conventional Helmholtz-based EPT, T-EPT does not impose homogeneity assumptions on the object, and requires only first order differences, which makes the method more accurate near tissue boundaries and more noise robust. Additionally, in contrast to integral equation-based approaches, estimation of the incident fields is not required. The EPT approach is derived from Maxwell's equations and evaluated on simulated data of a realistic tuned RF coil model to demonstrate its potential.....

The deformation behaviors of a droplet on surface of composite insulator can strengthen local electric field, which could finally lead to flashover. Both experiments and numerical simulations for dynamic behaviors of a droplet on the surface of a composite insulator under applied AC voltage are investigated in this paper. Experiments are performed to study the influences of water droplet’s volume and conductivity on the dynamic behaviors. Two critical parameters are proposed to describe the morphological change process of water droplet, and it is shown that the process can be divided into three stages. Moreover, these motion laws are explained by establishing theoretical factors and physical influence models. In addition, we perform computer simulation to study the dynamic behaviors of a water droplet under AC field, and the findings are in good consistency with our experimental results, proving the rationality of the theoretical physical model. It is found that the vibration frequency of droplet changes regularly with at different stages under the AC electric field.....