US Patent 7202831 Multi-band frequency loop-slot antenna

A loop-slot antenna defined by a conductive plate includes a first slot and a second slot. The first slot and the second slot divide the conductive plate into a first strip, a second strip and a patch element. The first slot is an L-shaped slot and includes a transverse slot section extending along the lower edge of the conductive plate and a longitudinal slot section extending along the left edge of the conductive plate and opening to the upper edge of the conductive plate. The first slot is operated at a first frequency. The first strip includes a transverse branch and a longitudinal branch that has a feed point. The second slot opens upward. The second strip has a free end on which a grounding point is disposed. The patch element is formed between the first and the second slots and operable at a second frequency.