An innovative balloonborne microjoule lidar (MULID) has been developed within the framework of the HIBISCUS project to provide nighttime measurements of visible and subvisible cirrus and aerosols. MULID has been designed to be a low-cost and an ultralow consumption instrument, due to the remote possibilities of payload recovery and the necessity of a low-weight battery power supply. Ground tests have been performed at the Observatory of Haute Provence (France), and the first technical flight has been made from Trapani, Italy, on a stratospheric balloon; finally, the instrument has been scientifically deployed during the pre-HIBISCUS and HIBISCUS tropical campaigns in Bauru, Brazil, in February 2003 and February 2004, respectively. A description of the instrument is provided together with the results of the ground-based and flight tests as well as an overview and discussion of the first results.

No abstract

Recent advances in the design of orthomode junctions (OMJs) have created new devices capable of achieving as much as a 1:4 bandwidth, while maintaining the high performance of traditional OMJ designs [1][2][3][4][5][6]. The new OMJ technology is based on an inverted-ridge structure, with four symmetrical feeding points for external balanced feeding, stabilizing the frequency dependence of the OMJ.Probes with one or more corrugations on the aperture can greatly enhance the radiated performance in terms of return loss, pattern symmetry, stability with frequency, and minimizing the cross-polar levels within the main beam of the probe. In the standard corrugated-horn literature [7], the upper limit on achievable bandwidth for corrugated horns is often stated to be somewhere between a ratio of 1: 1.5 to 1: 1.8, depending on the performance requirements. New strategies in corrugated-horn design and optimization are therefore required in order to take advantage of the increased bandwidth of the wide band OMJ technology. This paper discusses the achievable performance and limitations of wideband probes with multiple corrugated apertures. It shows measured and predicted design examples of apertures covering up to 1:2 bandwidth in the L-to Ka-band range.

Multiwavelength laser backscattersondes (MAS) have been widely used from a variety of airborne platforms for in situ measurements of optical properties of clouds and atmospheric particulate as well as their phase and composition. Recently, a new miniaturized LIDAR (MULID) has been developed using state-of-art technology for balloon borne profiling of the same quantities. A description of the two instruments, a survey of preliminary results obtained during test flights and indications for future use are given.

No abstract