This paper presents an internal dual-band antenna which has a planar-type radiator and operates (it the CDMA (824-894-MHz) and PCS (1750-1870-MHz) bands. The antenna characteristics at each band are optimized by tuning the size and length of the strip line's radiating segments. This antenna is composed of FR-4 substrate (thickness of 1 mm), a planar-type radiator, and 50 Omega coaxial feeding cable. The maximum measured radiation gains tire 0.94 and 1.89 dBi in the CDMA and PCS bands, respectively. The design of the proposed antenna and the experimental results are discussed. (c) 2005 Wiley Periodicals, Inc.