Biblio

The coupled thermohydroelastic processes of acoustic wave and heat propagation in weak viscous fluid and elastic bodies form the basis of dissipative acoustics. The problems of dissipative acoustics have many applications in engineering practice, in particular in the development of appropriate medical equipment. This paper presents mathematical models for time and frequency domain problems in terms of unknown displacements and temperatures in both the fluid and the elastic body. Formulated corresponding variational problems and constructed numerical schemes for their solution based on the Galerkin approximations. The method of proving the well-posedness of the considered variational problems is proposed.

The development of radar technology, Synthetic Aperture Radar (SAR) and Unmanned Aerial Vehicle (UAV) requires the communication facilities and infrastructures that have variety of platforms and high quality of image. In this paper, we obtain the basic configuration of triangle array antenna using corporate feeding-line for Circularly Polarized- Synthetic Aperture Radar (CP-SAR) sensor embedded on small UAV or drone airspace with compact, small, and simple configuration. The Method of Moments (MoM) is chosen in the numerical analysis for fast calculation of the unknown current on the patch antenna. The developing of triangle array antenna is consist of four patches of simple equilateral triangle patch with adding truncated corner of each patch and resonant frequency at f = 1.25 GHz. Proximity couple, perturbation segment, single feeding method are applied to generate the circular polarization wave from radiating patch. The corporate feeding-line design is implemented by combining some T-junctions to distribute the current from input port to radiating patch and to reach 2×2 patches. The performance results of this antenna, especially for gain and axial ratio (Ar) at the resonant frequency are 11.02 dBic and 2.47 dB, respectively. Furthermore, the two-beams appeared at boresight in elevation plane have similar values each other i.e. for average beamwidth of 10 dBic-gain and the 3 dB-Ar are about 20° and 70°, respectively.