A miniaturized monopole antenna with multiband operations for LTE, WWAN, WiMAX, and WLAN applications is presented. The antenna consists of multibranch strips and is fabricated on both sides of the FR4 substrate, which has a compact size of 10(L) ×10(W) ×0.8(T) mm3 to be embedded inside the Internet of Things (IoT) device as an internal antenna. Three operating bands covering 2.3–2.69, 3.4–3.7, and 5.15–5.85 GHz for the LTE, WWAN, WiMAX (2.3/2.5/3.5 GHz), and WLAN (2.4 GHz) systems are achieved with good radiation efficiencies. The proposed antenna can be embedded in the IoT device for the LTE, WWAN, WiMAX, and WLAN applications. The proposed antenna has advantages of sided structure, easy fabrication, low cost, and multiband operation. Also, the impedance matching performance of 3 resonant modes for the antenna can be adjusted flexibly. This makes the proposed antenna design suitable for practical applications. Details of the design process and the experimental results of the constructed antenna are presented.