In this paper, a very small 2.45 GHz printed antenna suitable for WLAN application is proposed. In order to decrease the size of the antenna, multi-layer substrate and shorting plate method are used. A microstrip line which can lead to a good impedance matching and four pairs of slot are used to obtain acceptable value of return loss at the desired frequency. These techniques are used as a mean that they can be applied in this antenna design and also can give an effect on the antenna characteristics. This antenna shows an omni-directional radiation pattern similar to that of a monopole antenna.