Dual-band microstrip patch antenna element with double U slots for GSM

A new dual-band microstrip patch antenna element is presented. The element configuration consists on a rectangular patch with double U slots and coaxial feeding. A prototype was designed, fabricated and tested to be used in a GSM 900/1800 base station antenna. Good agreement has been obtained between theoretical and experimental results. To provide the required bandwidth for both the GSM bands a double-layer structure is under analysis.