The cloud of cold atoms produced by a Magneto-Optical Trap is known to exhibit instabilities. We examine in this paper in which limits it could be possible to realize an experimental trap similar to the configurations studied theoretically, i.e. mainly traps where one direction is privileged. We study the static behavior of an anisotropic trap, where anisotropy results essentially from the use ...

We report VLBI polarimetric observations of the steep spectrum compact radio source 3C138. The relatively small range of Faraday rotation measured in the outer jet and hotspot region suggests that the jet is not being confined by a dense plasma. These results are inconsistent with the “frustrated jet” scenario and are consistent with the “young source” scenario. Evidence is given for extensive ...

EMISAR is a fully polarimetric, dual frequency (Land Cband) SAR system designed for remote sensing applications. The data are usually processed to 2x2 m resolution. The system has the capability of C-band cross-track single-pass interferometry and fully polarimetric repeat-pass interferometry. The SAR is operated at high altitudes on a Gulfstream G-3 jet aircraft. The system is very well calibr...

In this paper, a new dual-frequency, compact antenna, which uses an H-shaped microstrip patch with a shorting pin, is described. Compared with the conventional rectangular patch antenna, this antenna can achieve both a significant reduction of antenna size and a dual-frequency operation with a single feed. More freedoms for tuning the resonant frequencies, the frequency ratio, and the input imp...

In the next few years GPS will start broadcasting civil signals suitable for aviation use on both the L1 and L5 frequencies. In addition, Galileo and other constellations will offer an even greater number of dual frequency ranging measurements. The Wide Area Augmentation System (WAAS) and the other Satellite Based Augmentation Systems (SBASs) can also be updated to exploit these new signals. Su...

Conventional metallic waveguides have several major advantages, including low propagation losses and high power transmissions in the microwave frequency range. One disadvantage of metallic waveguides is that the propagation frequency band is limited at frequencies above the cutoff frequency fc. The usable frequency range is therefore restricted to fc < f < 2fc, because the TE20 mode can exist i...

The study of Microstrip patch antennas have made great progress in recent years. Compared with conventional antennas, Microstrip patch antennas have more advantages and better prospects. They are lighter in weight, low volume, low cost, low profile, smaller in dimension and ease of fabrication and conformity. Moreover, the Microstrip patch antennas can provide dual and circular polarizations, d...

Terahertz dual frequency comb spectroscopy (THz-DFCS) yields high spectral resolution without compromising bandwidth. Nonetheless, the resolution of THz-DFCS is usually limited by the laser repetition rate, which is typically between 80 MHz and 1 GHz. In this paper, we demonstrate a new method to achieve sub-repetition rate resolution in THz-DFCS by adaptively modifying the effective laser repe...