Antennas for IoT Application: An RF and Microwave Aspect of IoT

Introduction

The diverse ecosystem of Internet of Things (IoT) brings along uncountable end-devices utilizing all sorts of radio modules, sensors/actuators, batteries/cells, MEMS devices, energy harvest techniques, and on top of all, antennas. The choice and design of the antenna is application dependent and varies depending on the frequency range, transmission strength and availability of space. Unlike the high-throughput wireless networks such as 5G, IEEE 802.11ax and WiGig etc. that utilize vast continuous spectrum space, IoT network smartly transmits/receivers small chunks of data in an IoT network in various network topologies like star, mesh and/or point-to-point. Most of the times, the job of establishing such types of links is accomplished by some common and relatively less complex types of omni-directional antennas such as wire antennas, rubber duck, patch, whip, PCB and on-chip antenna structures. Several IoT development kits and platforms such as Arduino GSM and Qualcomm IoE make use of similar antennas structures for GPS, Bluetooth and Wifi communication. Some applications such as Medical Body Area Networks (MBAN) and wearable electronics also require antennas to be low-profile and conformal to the surface of the device. This persuades the need of developing antennas specific to end-device and tailored to meet specialized applications requirements. Antennas for IoT can either be categorized according to their bands of operation or the application; Unlicensed ISM bands e.g. frequencies around 2.4 GHz are more common in IoT development platforms. Whereas, some applications also include antennas for licensed bands such as Avionics applications. The table below highlights few antennas frequently used in IoT applications with their frequency bands.