913 research outputs found
Film-loaded Strip- and Slot-type SAW Waveguides for IntegratedAcousto-Optical Polarization Converters in LiNbO3
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A platelet W-band feed horn-OMT assembly
No full textFuture Cosmic Microwave Background polarisation experiments will require large detector arrays to achieve the required sensitivity for precise measurements. New cost- and time-effective techniques are required for mass production of high performance passive components. We present electromagnetic test results on an assembly of feed horn and OMT prototypes, operating in the W-band and fabricated by means of 'platelet' technique. The good level of isolation and return loss (respectively >45 dB, >30 dB on 20% bandwidth) for both polarizations are in agreement with numerical simulations, indicating good matching between components. Radiation patterns are also in agreement with simulations, with cross-polarization level < -30 dB on a 20% bandwidth. These results confirm the good design, manufacturing and assembling of the prototypes
Millimeter-Wave Passive Components of Correlation Radiometers for Polarization Measurement
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Design and Verification of a Q-Band Test Source for UAV-Based Radiation Pattern Measurements
No full textIn the last years, the unmanned aerial vehicles (UAVs) generated significant innovations in in situ antenna measurements. UAV-mounted test sources have been exploited to characterize the radiation pattern of receiving antennas and arrays for HF radars, radio telescopes in very high-frequency (VHF) band, and up to the X -band for radar characterization. A UAV test source operating in the Q -band has been recently developed within the large-scale polarization explorer (LSPE) project. It will be used for the in situ validation of a ground-based cluster of coherent polarimeters for cosmology observation. This article presents the payload solution that is actually applicable to general UAV-based radiation pattern measurements in the Q -band. It is based on a phase-locked loop synthesizer and an active multiplier coupled with a power detector to compensate for signal power drifts in postprocessing. Relevant system tests have been performed in both laboratory environment and operative conditions. The measured outdoor radiation patterns are in good agreement with both the anechoic chamber measurements and simulated data
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