IoT antennas increasingly must handle frequencies well beyond the ISM band and into the cellular and 5G spectrum.
Christian Koehler, Felisa Chuang • TE Connectivity
The Internet of Things (IoT) bridges the gap between the physical and virtual worlds. Machine to machine (M2M) communications–via low-powered networks such as UWB, WLAN, Zigbee or Bluetooth–has helped drive IoT adoption. Even more so, it is the advent of LPWANs like NB-IoT, LTE Cat-M and 5G high-efficiency transmission that have fueled IoT growth. 5G shifts the paradigm toward sophisticated IoT solutions for industrial and environmental concerns.
Fiber optic cable has paved the way by making it practical for multiple wireless channels to run data over high-speed 5G networks and ensure uninterrupted transmission. Connectivity dynamics also benefit from the application of cloud-like concepts to both radio access and core networks. For example, C-RAN, the fast-growing global cloud radio-access network, focuses on BBU (baseband unit) pooling and the adoption of cloud technologies. While these are two different technologies, they share a common denominator: Both demand high-speed, high-data, high-density, and reliable and rugged connectivity.
Enter the antenna. Antennas play a complex role in the dynamics of the IoT. Rather than view antennas as passive products–whether external or embedded–engineers should treat them as integral to the creation of IoT applications.
There are already commercial examples of how multiple antennas are being used to work with 5G networks and support IoT applications. Active Antenna Systems (AAS) are commonly adopted to increase the capacity and coverage of radio streams. These systems often include interface amplifiers, low-noise amplifiers, switches, and pre-drivers to transmit and receive data via massive Multiple Input Multiple Output Technology (MIMO). They also feature a tight integration of RF electronics with the antenna to enable miniaturization and boost efficiency.
Advanced Antenna Systems (another AAS) are also becoming more widely used. They comprise an antenna array closely integrated with hardware and software to implement features such as steerability for adapting antenna radiation patterns to rapidly time-varying traffic and multi-path radio transmission conditions.
Such complexities have made the process of choosing an antenna more challenging. It is not unusual for IoT applications to include up to 12 antennas inside a mobile-phone-sized device. These antennas must manage different redundancies and services while radiating and receiving independently from one another, thus putting a premium on antenna isolation.
Also critical is operation on secure networks. A wide range of antennas can handle Wi-Fi, Bluetooth and GPS applications. However, cellular antennas are becoming increasingly important. The exponential growth of wireless traffic is causing more and more interference, so spectral efficiency is key. Antennas must play a role in keeping wireless traffic out of neighboring channels.
Cellular antennas also help address certification and regulatory requirements. Cellular carriers must adhere to specifications and standards set by the Global System for Mobile Communications Association (GSMA) and the 3rd Generation Partnership Project (3GPP). There are multiple rounds of testing involved in obtaining regulatory approval from authorities such as the Federal Communications Commission (FCC) in the U.S., or the European Telecommunications Standards Institute (ETSI) and Radio Equipment Directive (RED) in the EU.
It makes sense to look at two major trends in IoT use of antennas: smart tracking and smart buildings.
Smart tracking is generally defined as hardware and software technologies used to collect tracking data from multiple sources and transform that data into information for making informed decisions. It can play a role on-board diagnostics (OBD) or be used for tracking physical assets in transport and distribution.
A typical smart tracking application may involve decisions about antenna radiation and orientation, how to handle harsh environmental conditions, mitigating sources of signal interruption, battery power, and similar problems. An example of how one startup addressed these issues is as follows:
An IoT startup in global tracking used a chip antenna that did not allow for the granular tracking data needed, and the developers did not understand the complex RF requirements involved. A new system that solved these problems took the form of custom-designed, surface-mount antennas for 5G connectivity that made possible a reusable, smart system–more like a mobile phone than an IoT device–for real-time parcel tracking. The new antennas also weighed less than the original system and reduced the cost and size of the PCB while also improving performance.
Use of surface-mount antennas also created a more efficient and repeatable manufacturing process. All in all, the redesign of the antenna system led to a review of the overall design that improved battery life and to a reconfiguring of the PCB layout that maximized the ground plane to avoid interference among the radios involved.
Smart buildings are part of the fast-growing “proptech” industry–the application of information technology and platform economics to real estate. The primary motivation for smart buildings is energy utilization, but other focus areas include: security, building management and eco-friendly living.
There are numerous technological challenges associated with smart building antennas. They include path loss from building construction materials, interference congestion, and poor 5G signal penetration to the building interior. Here’s an example of how one user addressed these issues:
A real estate developer constructed a smart building in a major metropolitan area. The building featured security and surveillance protocols, real-time energy reporting, and predictive maintenance models. Floor plans included smart lighting, air quality monitoring and intelligent parking. Cybersecurity was also paramount because smart buildings are vulnerable to cyberattacks.
There were several antenna systems handling various IoT smart building systems. They included MIMO assemblies that both allowed wireless servers to deliver uninterrupted service to building occupants and brought cellular network service indoors. Embedded antennas handled smart indoor cameras and cloud-based automated access control systems. These access systems included features such as customizable credential options which included mobile apps, personalized key cards, key fobs, and links sent to a mobile phone.
Also present were 3D antenna assemblies for real-time monitoring of electric, water and gas utilities. Similarly, 3D antennas facilitated the bundling of various smart energy-saving technologies into hubs and group control functions. These hubs then sent data about lighting, temperature, humidity, and other factors to the cloud. Finally, LPWAN antennas allowed real-time cloud visualizations, including real- time alerts and visuals, used to monitor and maintain the building from miles away.
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