ABSTRACTA compact printed monopole antenna with dual‐band operation at 1.8 GHz (GSM Band) and 5.2 GHz (Wi‐Fi Band) is presented. The antenna consists of a modified U‐shaped radiating patch with a triple rectangular defect in the ground plane. The antenna is fed by a cross‐shaped feed line, which helps in realizing the dual‐band operation. The antenna has been designed using RO4350 substrate. The design size achieved is 19 × 28 mm2. An impedance bandwidth of about 32% at 1.8 GHz and about 29% at 5.2 GHz for 10 dB return loss has been achieved. A size reduction of about 12% in comparison with a similar antenna without defected ground structures has been achieved. The proposed antenna has been fabricated and tested, and a good agreement between simulated and measured results is seen. Acceptable E‐plane and H‐plane radiation patterns have been observed through simulations, and a peak antenna gain of about 2.8 dBi has been achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1810–1813, 2015