A W-band dual-polarized Cassegrain antenna for cloud radar is proposed. The aperture diameter of the main reflector of the antenna is 50 cm. By using a modified Magic-T structure in the feed horn, the antenna is dual-polarized with high port isolation. The measured results show that the port isolation is 44.7 dB. The gains are 47.3 dB and 49.5 dB for the two ports at 94GHz, respectively, and th...

The NRAO has established a clear strategic plan (Lo et al., 2009, Astro2010 position paper, The Impact of the National Radio Astronomy Observatory) for scientific discovery and technical development in the next decade which leads naturally to a long range vision for radio astronomy. This is one of five papers outlining these activities for the Program Prioritization Panel. Here we describe in f...

Cassegrain Reflector Antenna Design consists of various effects caused by blockage and its effect on overall performance. The design for minimum blockage condition results in geometry that offers lower amount of blockage and increased spillover past the subreflector. To avoid this, optimized design of the antenna results in geometry that offers lower amount of spillover past the edges of the ma...

Context. The use of large-format focal plane imaging arrays employing multiple feed horns is becoming increasingly important for the next generation of single dish sub-mm telescopes and cosmology experiments. Such receivers are being commissioned on both general purpose, common user telescopes and telescopes specifically designed for mapping intensity and polarisation anisotropies in the cosmic...

This paper shows injection molded millimeter-wave horn array antenna for the 1-dimensional APAA(Active Phase Array Antenna). The antenna is composed of horn antennas, grooved circular waveguide polarizers, E-plane T-junctions, and E-plane bends employing dielectric waveguides. This structure makes it possible to manufacture a feed circuit and radiating elements as an integrated unit by using in...

Abstract The synthesis of both covalently bonded chlorine and nitrogen-doped carbon materials (Cl-N-CNMs) has been little studied. In this paper we report on the investigation Cl-N-CNMs using a feedstock containing mixture dichlorobenzene (DCB), acetylene acetonitrile over Fe-Co/CaCO 3 catalyst an injection CVD method at 800 °C. By varying acetonitrile:DCB concentration ratio (66.7:33.3; 33.3:6...

We define here a new symmetry operator called reciprocation. Apertures that remain unchanged afler reciprocation are called self-reciprocal, and have a number of unique properties. When excited suddenly by a voltage, a self-reciprocal aperture becomes an antenna. This antenna is an approximation to a TEM horn, to a lens IRA (TEM feed + lens), or to a reflector IRA (TEM feed + reflector). Becaus...

ABSTRAKPada studi ini dilakukan analisis penambahan batang metal berbentuk persegi di dalam feed horn piramida antena reflektor parabola untuk meningkatkan performansi gain, beamwidth dan side lobe level. Kebutuhan utama radar maritim adalah memiliki gain yang besar ≥ 27 dB, kecil ≤ 2o, level rendah -30 dB. Oleh karena itu, perlu diajukan teknik desain dengan performasi Hasilnya dapat menjadi 3...