In this paper, circular and hexagonal array geometries for smart antenna applications are compared. Uniform circular (UCA) and hexagonal arrays (UHA) with 18 half-wave dipole elements are examined; also planar (2 concentric rings of radiators) uniform circular (PUCA) and hexagonal arrays (PUHA) are considered. The effect of rotating the outer ring of the PUCA is studied. In our analysis, the me...

The contrawound toroidal helix antenna with constant current is examined; it has an omnidirectional pattern in the toroid plane. Radiation resistance is derï ed for the dipole mode, and results are ̈alidated by moment-method calculations. The radiation Qs of these antennas are greater than one million, making them unsuitable as dipole mode radiators. Ratios of loop-mode to dipole-mode radiation ...

BACKGROUND An axisymmetric finite element method (FEM) model was employed to demonstrate important techniques used in the design of antennas for hepatic microwave ablation (MWA). To effectively treat deep-seated hepatic tumors, these antennas should produce a highly localized specific absorption rate (SAR) pattern and be efficient radiators at approved generator frequencies. METHODS AND RESUL...

– In this paper we extend for the case of Maxwell equations the " X-shaped " solutions previously found in the case of scalar (e.g., acoustic) wave equations. Such solutions are localized in theory: i.e., diffraction-free and particle-like (wavelets), in that they maintain their shape as they propagate. In the electromagnetic case they are particularly interesting, since they are expected to be...

Mechanically pumped single-phase fluid loops are well suited for transporting and rejecting large amounts of waste heat from spacecraft electronics and power supplies. While past implementations of such loops on spacecraft have used moderate operating temperatures (less than 60oC), higher operating temperatures would allow equivalent heat loads to be rejected by smaller and less massive radiato...

This paper presents the electromagnetic interference and electromagnetic susceptibility characteristics of the railway telecommunication intra-subsystem. These are for assessing the electromagnetic compatibility inside the railway telecommunication subsystem and providing input data for electromagnetic compatibility analysis of other subsystems (intra-system analysis). This paper shows the opti...

– In this paper we extend for the case of Maxwell equations the " X-shaped " solutions previously found in the case of scalar (e.g., acoustic) wave equations. Such solutions are localized in theory: i.e., diffraction-free and particle-like (wavelets), in that they maintain their shape as they propagate. In the electromagnetic case they are particularly interesting, since they are expected to be...

An energy-efficient thermal control management method for space remote sensors using optical, mechanical, electrical, and integration is proposed. The satellite power resources are insufficient, so an loop heat pipe (LHP) designed six intermittently operating detectors. charge-coupled device (CCD) has a total generation of 72 W operates 8 min per orbital cycle. LHP includes capillary pump, cold...