Optical Designs for a Multi-Beam 340 and 625/640 GHz Spaceborne Climate Research Instrument

We report on an ongoing study where different optical configurations for a multi-beam limb-viewing (four to eight receiver channels at 340 and two channels at 625 GHz) spaceborne instrument for climate research are presented and compared. The optical configurations are analyzed in terms of optical performance (gain, side lobe levels, beam efficiency etc.), weight and size of the overall instrument envelope. Using ideal fundamental Gaussian beam modes and numerical tools relying on ray-tracing and physical optics methods, the different configurations are designed and evaluated. Preliminary results indicate that a 1.3 m x 0.65 m primary reflector can be used in a configuration that includes a relay optics system having two to four elements. In addition to the limb-viewing instrument, there will be an additional instrument operating at 640 GHz for observing clouds in nadir mode

Quasi-optical phase retrieval of radiation patterns of non-standard horn antennas at millimetre and submillimetre wavelengths

The location of the phase centres of antenna feeds is critical for optimised sensitivity and resolution on reflector antennas and telescopes. While the measurement of the far-field intensity patterns of such feeds is relatively straightforward, the direct recovery of their phase patterns requires access to expensive phase sensitive instrumentation such as a vector network analyzer. We present an inexpensive alternative quasi-optical technique, analogous to off-axis holography at visible wavelengths, that allows for the phase curvature of the feed pattern, and thus the phase centre, to be recovered with sufficient accuracy for optimizing aperture efficiency and resolution on a reflector antenna. We discuss the accuracy of the technique and compare results for the case of a specialized horn antenna for CMB polarization operating at 100GHz, using both the quasi-optical method and a vector network analyzer as a bench mark measurement tool for verification of the approach. We also include some measurements made of a lens antenna fed by a bare waveguide radiator

Determination of the Phase Centers of Millimeter-Wave Horn Antennas Using a Holographic Interference Technique

In this paper, we discuss how a holographic interference technique can be applied in the experimental determination of the phase centers of non-standard horn antennas in the millimeter-waveband. The phase center is the point inside the horn from which the radiation appears to emanate when viewed from the far-field, and knowing its location is necessary for optimizing coupling efficiencies to quasi-optical systems. For non-standard horn designs, and other feed structures, the phase center may be difficult to reliably predict by simulation, in which case, before committing to antenna manufacture, there is a requirement for it to be determined experimentally. Although the phase center can be recovered by direct phase measurement of the far-field beam pattern, this usually involves expensive instrumentation such as a vector network analyzer for millimeter wave horn antennas. In this paper, we describe one inexpensive alternative, which is based on measuring the interference pattern in intensity between the radiation from the horn of interest and a reference beam derived from the same coherent source in an off-axis holography setup. The accuracy of the approach is improved by comparison with the interference pattern of a well-understood standard horn (such as a corrugated conical horn) in the same experimental setup. We present an example of the technique applied to a profiled smooth-walled horn antenna, which has been especially designed for cosmic microwave background (CMB) polarization experiments

Quasi-optical phase retrieval of radiation patterns of non-standard horn antennas at millimetre and submillimetre wavelengths

The location of the phase centres of antenna feeds is critical for optimised sensitivity and resolution on reflector antennas and telescopes. While the measurement of the far-field intensity patterns of such feeds is relatively straightforward, the direct recovery of their phase patterns requires access to expensive phase sensitive instrumentation such as a vector network analyzer. We present an inexpensive alternative quasi-optical technique, analogous to off-axis holography at visible wavelengths, that allows for the phase curvature of the feed pattern, and thus the phase centre, to be recovered with sufficient accuracy for optimizing aperture efficiency and resolution on a reflector antenna. We discuss the accuracy of the technique and compare results for the case of a specialized horn antenna for CMB polarization operating at 100GHz, using both the quasi-optical method and a vector network analyzer as a bench mark measurement tool for verification of the approach. We also include some measurements made of a lens antenna fed by a bare waveguide radiator

Revisão latino-americana do International Design Scoreboard: levantamento de dados para informação de políticas públicas de design

There are many difficulties in measuring the impact of design on the development of nations, which in turn undermines the value of design as a tool for national competitiveness. This study aims to contribute to the gathering of data which can guide the development of the national design sector and design promotion programs. For this purpose, isolated data is not sufficient. Instead, accurate, clear and objective data is required to enable analyses and comparisons with other references in order to draw conclusions and direct actions. This research builds on the International Design Scoreboard (2009), which is characterised by the use of indicators that quantify the design capacity of nations, through data that is comparable in both absolute and relative terms. This methodology utilises a number of metrics that allowed the rearchers to develop an overview of the scenario of design in three Latin American countries – Brazil, Colombia and Uruguay – in comparison with other countries around the world.Keywords: public policies, design, indicators, scoreboard, Brazil, Colombia, Uruguay.Existem diversas dificuldades na mensuração do impacto do design no desenvolvimento dos países, o que contribui para a subvalorização do design como uma ferramenta para o aumento da competitividade. O presente estudo visa contribuir no levantamento de informação a fim de orientar o desenvolvimento do setor do design e dos programas de fomento à atividade nos países. Para isso, dados isolados não são suficientes. São necessários dados concisos, claros e objetivos que permitam análises e comparações com outras referências, a fim de elaborar conclusões e ações. Nessa direção, a metodologia escolhida foi o IDS – International Design Scoreboard (2009), caraterizada pelo uso de indicadores que contribuem para evidenciar a capacidade de design das nações, mediante a coleta de dados consistentes e uniformes que possibilitem a comparação. Dita metodologia faz uso de uma estrutura enxuta de indicadores que permitiu aos pesquisadores ter uma primeira visão concreta da situação real do design em três países da América Latina – Brasil, Colômbia e Uruguai – frente a outros países ao redor do mundo.Palavras-chave: políticas públicas, design, indicadores, scoreboard, Brasil, Colômbia, Uruguai

Revisão latino-americana do International Design Scoreboard: levantamento de dados para informação de políticas públicas de design

There are many difficulties in measuring the impact of design on the development of nations, which in turn undermines the value of design as a tool for national competitiveness. This study aims to contribute to the gathering of data which can guide the development of the national design sector and design promotion programs. For this purpose, isolated data is not sufficient. Instead, accurate, clear and objective data is required to enable analyses and comparisons with other references in order to draw conclusions and direct actions. This research builds on the International Design Scoreboard (2009), which is characterised by the use of indicators that quantify the design capacity of nations, through data that is comparable in both absolute and relative terms. This methodology utilises a number of metrics that allowed the rearchers to develop an overview of the scenario of design in three Latin American countries – Brazil, Colombia and Uruguay – in comparison with other countries around the world.Keywords: public policies, design, indicators, scoreboard, Brazil, Colombia, Uruguay.Existem diversas dificuldades na mensuração do impacto do design no desenvolvimento dos países, o que contribui para a subvalorização do design como uma ferramenta para o aumento da competitividade. O presente estudo visa contribuir no levantamento de informação a fim de orientar o desenvolvimento do setor do design e dos programas de fomento à atividade nos países. Para isso, dados isolados não são suficientes. São necessários dados concisos, claros e objetivos que permitam análises e comparações com outras referências, a fim de elaborar conclusões e ações. Nessa direção, a metodologia escolhida foi o IDS – International Design Scoreboard (2009), caraterizada pelo uso de indicadores que contribuem para evidenciar a capacidade de design das nações, mediante a coleta de dados consistentes e uniformes que possibilitem a comparação. Dita metodologia faz uso de uma estrutura enxuta de indicadores que permitiu aos pesquisadores ter uma primeira visão concreta da situação real do design em três países da América Latina – Brasil, Colômbia e Uruguai – frente a outros países ao redor do mundo.Palavras-chave: políticas públicas, design, indicadores, scoreboard, Brasil, Colômbia, Uruguai