With the development of wireless communications,
integration becomes a trend to accommodate the rapidly
increasing amount of electronic components. To reduce the
complexity and cost of the integration, devices which can fulfil
many roles are becoming popular. Multi-band antennas are such
a solution for this trend as they increase the flexibility and
functionality of devices. Many different designs of multi-band
antennas can be found in [1] - [4]. Printed monopoles have
wideband performance and nearly omni-directional radiation
patterns which are suitable for mobile phones, base stations, and
other personal communications.