An integrated multi‐band monopole antenna with three radiating strips having a compact structure to provide a double‐wideband operation in an Internet of Things (IoT) device is studied and presented. The proposed antenna is very suitable for the heterogeneous multi‐access network integration trend applications in mobile or fixed IoT devices, which can cover the 4G and 5G operating frequencies, the vehicle‐to‐everything and dedicated short range communication band from the IEEE 802.11p based wireless technology, the WiFi 6 band from the IEEE 802.11ax, the WLAN, and the WiMAX operating frequencies. The proposed antenna is manufactured on a single side of high quality FR4 substrate, which has a compact dimension of 8(L) × 8(W) × 0.8(T) mm3, and is composed of multibranch strips, namely, multiple curved shapes, L shapes to be embedded in the IoT device as an built‐in antenna. There are two operating bands designed between 2355‐5000 and 5112‐7000 MHz with well radiation efficiencies. The measured results show that the two operating bands are satisfied with reflection coefficient better than −6 dB, and total efficiencies of higher than 44% to 83%. In addition to that, the proposed antenna with multiband operation having a single side structure is simple to manufacture, low cost, low profile, and compact advantages.