A Spiral-Shaped Printed Monopole Antenna for Mobile Communications

A planar monopole antenna consisting of a printed metal strip of rectangular spiral shape is studied. The spiral generates two resonance modes and radiates at two frequency bands. An example design is given where the lower operating band covers the GSM900 band, and the upper operating band covers DCS1800, PCS1900 and UMTS2000 bands. This multi-band antenna is compact and lightweight and it can be fabricated at very low cost by etching the spiral on an FR4/Epoxy substrate and feeding with a 50 ω microstrip line.