  A novel and compact dual band planar antenna for 2.4/5.2/5.8-GHz wireless
local area network(WLAN) applications is proposed and studied in this paper.
The antenna comprises of a T-shaped and a F-shaped element to generate two
resonant modes for dual band operation. The two elements can independently
control the operating frequencies of the two excited resonant modes. The
T-element which is fed directly by a 50 $\Omega$ microstrip line generates a
frequency band at around 5.2 GHz and the antenna parameters can be adjusted to
generate a frequency band at 5.8 GHz as well, thus covering the two higher
bands of WLAN systems individually. By couple-feeding the F-element through the
T-element, a frequency band can be generated at 2.4 GHz to cover the lower band
of WLAN system. Hence, the two elements together are very compact with a total
area of only 11$\times$6.5 mm$^{2}$. A thorough parametric study of key
dimensions in the design has been performed and the results obtained have been
used to present a generalized design approach. Plots of the return loss and
radiation pattern have been given and discussed in detail to show that the
design is a very promising candidate for WLAN applications.
