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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.

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.

An internal etching for three‐dimensional structures (ETS) antenna capable of operating in the 810–960, 1370–1450 and 1710–2630 MHz bands, respectively, for long‐term evolution (LTE)/wideband code division multiple access (WCDMA)/2.4 GHz industrial, scientific and medical (ISM) band operations suitable for being embedded within a smart wrist wearable wireless mobile communication device is proposed. The proposed antenna radiation efficiency can achieve 37.8–55.3% from 810–960 MHz, 53.1–92.63% from 1370–1450 MHz and 52.9–93.1% from 1710–1630 MHz for LTE/WCDMA bands and 87.4% for ISM band without the hand phantom in the free space condition. The antenna radiation efficiency of the LTE/WCDMA and ISM bands is reduced by half because of the hand phantom with lossy material properties. Furthermore, the health risk related to exposure to electromagnetic radiation, the specific absorption rates of the device are evaluated and the results were far below the limits required by the Federal Communications Commission (FCC) organisation. The embedded three‐dimensional (3D) multi‐band antenna can be adapted for the smart wrist wearable wireless mobile communication device. This study breaks the pattern that wearable devices must work with mobile phones. The wearable device proposed herein can directly communicate with the carrier base station independently.

A compact monopole and inverted‐F antenna design for 2.4 GHz ISM band (2400–2485 MHz) and 1.575 GHz GPS operations suitable to be embedded within a wrist‐worn wireless communication device is presented. Those antennas are fabricated on a polycarbonate and acrylonitrile‐butadiene‐styrene blend substrate with a three‐dimensional etching process for irregular plastic materials. The wrist‐worn device with and without a solid hand phantom model is evaluated. The radiation efficiency of the antennas can reach 80% for the ISM band and 63% for the GPS band without the hand phantom model. With the hand phantom model, the radiation efficiency reduces in half for both the ISM and GPS bands due to lossy materials in the phantom model. Good agreements between simulations and measurements are obtained. Moreover, the specific absorption rate of the device for the ISM band is measured and the results are much lower than the limit required by the FCC. This build‐in antenna design can be applied in the wearable wireless communication device.