RESUMO
A 3D-printed phased array consisting of four H-Sectorial horn antennas of 200 g weight with an ultra-wideband rectangular-waveguide-to-microstrip-line transition operating over the whole LMDS and K bands (24.25-29.5 GHz) is presented. The transition is based on exciting three overlapped transversal patches that radiate into the waveguide. The transition provides very low insertion losses, ranging from 0.30 dB to 0.67 dB over the whole band of operation (23.5-30.4 GHz). The measured fractional bandwidth of the phased array including the transition was 20.8% (24.75-30.3 GHz). The antenna was measured for six different scanning angles corresponding to six different progressive phases α, ranging from 0° to 140° at the central frequency band of operation of 26.5 GHz. The maximum gain was found in the broadside direction α = 0°, with 15.2 dB and efficiency η = 78.5%, while the minimum was found for α = 140°, with 13.7 dB and η = 91.2%.
RESUMO
El neumomediastino espontáneo (NE) es una entidad infrecuente, de curso habitualmente benigno y resolución espontánea. Se puede vincular a factores desencadenantes o presentarse en ausencia de ellos. se describe un caso de NE y se revisa la literatura puntualizando en aspectos epidemiológicos, diagnósticos y terapéuticos. se enfatiza en el alto índice de sospecha clínica requerido para su diagnóstico, principalmente en pacientes jóvenes que se presentan con dolor torácico.
