A microstrip antenna employing a rectangular radiating element having a Uaped slot oriented parallel to the length of the radiating element and employing a single feedline coplanar with the radiating element. The slotted radiating element has three resonances: a length resonance polarized parallel to...http://www.google.fr/patents/US4766440?utm_source=gb-gplus-shareBrevet US4766440 - Triple frequency U-slot microstrip antenna
