This letter presents a dual-band circularly polarized patch antenna dedicated to satellite communications. The dual-band behavior is obtained by inserting a small X-band microstrip patch antenna into a large L-band one. Both patches are printed on the same substrate and fed by electromagnetic coupling through two perpendicular slots etched in their ground planes. These slots are fed by two different 90 microstrip branch-line couplers printed on a stacked lower substrate. A prototype of the antenna was realized with a 1.5-mm-thick upper layer substrate and a 0.758-mm-thick feed layer substrate, both of the same dielectric material with a relative permittivity of r = 2 22. Simulation and measurement results are presented, showing this compact dual-band antenna achieves the required Meteosat specifications in terms of frequency bandwidth, circular polarization bandwidth, and isolation between the two communication bands.Index Terms-Circular polarization, dual-band antennas, hybrid branch-line couplers, microstrip patch antennas, satellite communications.

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The p6Li i q'Be reaction has been investigated at Tp,= 683 MeV using the Satume synchrotron. ' 1 mesons were detected wilh the high-resolution light neulral m m n spectrometer PINUT. The small-angle CM differential mass section for the production of the sum of the first few levels of 'Be was found to be 4.6 f 3.8 nb sr-'. This value is about one o d e r of magnitude less than that for the pd -+ q'He reaction at lhe Same q CM momentum.

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