A dual‐band horizontally polarized (HP) antenna with omnidirectional radiation patterns is presented in this paper. The HP antenna is a vertical slot backed with a metal box, which is excited by a tapered feeding patch with a U‐slit for dual‐band operation. Good omnidirectional radiations are observed. A dual‐band dual‐polarized (DP) antenna is then developed by adding a dual‐band vertically polarized (VP) element to the HP element. The VP element is composed of two horizontal slots excited by a two‐branch feedline. The dual‐band DP antenna achieves an overlapped impedance bandwidth of 6% (2.34‐2.5 GHz) for the lower band and 15% (5.06‐5.91 GHz) for the upper band with an isolation of higher than 35 dB. Both the dual‐band HP and DP antennas are suitable to serve as WiFi/WLAN/ISM antennas for short‐range, low power wireless communications.