IoT Antennas for Connected Lighting

The Internet of Things (IoT) provides the best solutions for creating smart and colorful spaces through connected lighting. Once adopted, the advantages of connected lighting systems are diverse: The smart system can be used to monitor the environment and personalize the user experience while offering reliable illumination with low latency and energy-harvesting techniques. It becomes very crucial to understand the choice of antennas to maximize the power savings and extend the battery life of the system.

Several intelligent systems using a number of base stations and sensor nodes fitted with LED lights are integrated together through wired and wireless networks to form a connected lighting system. The machine-to-machine communication (M2M) drives these in-network systems to exchange data seamlessly between devices and deliver the user desired services.

In order to monitor and control the system, the devices in the connected lighting network should be able to communicate in one or more of the standard protocols. These include the emerging 5G, Bluetooth, NFC, LoRa WAN, ISM, ZigBee and NB-IoT with spectrum use between 400 MHz and 6 GHz for extended battery life. The ubiquity of Wi-Fi makes it easily available and supports higher data rates.

The following list discusses the key differences, features and benefits of Abracon’s antenna solutions:

1. Abracon offers a variety of traditionally used external whip antennas (AEACAQ190012 – S868 and AEACAQ190012 – S915) specially designed for IoT applications that work at 868 MHz and 915 MHz, respectively. The narrow bandwidth antennas with very low standing wave ratio (VSWR) are linearly polarized antennas that can be combined or used as stand-alone elements in a MIMO system. These high-efficiency antennas (up to 66% in the pass band) producing omni-directional pattern with a low input power (up to 10 W) can be implemented in almost any connected lighting system needing to cover a large area in the network. They do not require a separate ground plane as the outer shielding often acts as one, which makes it easy to test and measure the characteristics without the PCB.
   
2. Chip antennas offer the most compact form factor for NB-IoT applications with space constraints. In return, the performance or the gain is slightly under par when compared with other robust antennas, but they require significantly less input power. While designing these, the ground plane size and shape require equal importance, as there is a direct effect on the radiation pattern just like the monopoles. Abracon’s ACAR3705-SB and dual-band ACAR3005 – C2WB antenna solutions offer up to 60% and 55% efficiency rates at 791 MHz and 824 MHz while having a wide band response between 698 MHz - 960 MHz and 824 MHz – 960 MHz, 2400 MHz – 2500 MHz.
   
3. The simplest antennas are the patches, which are often found in mobile phones. These lightweight, low-cost solutions are very compact for integration into the wireless devices connected in the network for monitoring and remote controlling of the connected lighting systems. These usually have a ground plane underneath the dielectric substrate and can be fabricated by different etching or 3D printing methods. When optimally designed, they exhibit a good performance over a wider bandwidth in and over the UHF spectrum. Some patch antennas are polarized to achieve more consistent reception. The polarization of patches is often RHCP or LHCP, though dual-polarization can be designed to exhibit in a single patch. The only constraint when opting for patches is that even a slight change in the PCB design affects the matching. Hence, with an availability of sufficient clearance area around the antenna, the patches offer good levels of efficiency.

Other main factors could help increase performance: The design can use an antenna with an amplifier or replace omni-directional antennas with directional beam steering to generate higher gain levels. Use line of sight in the communication links to avoid reflections and scattering, and consider opting for lower frequency links to increase the coverage area.

Many antenna options are available for the connected lighting system, but demand is high for elevated performance in terms of efficiency and range, minimized input power, and effective area while considering the size and weight of the antennas that go into these systems. Often, multiple antennas will have to be planted inside the same node. The engineers will have to keep in mind the flexibility in designs and set optimization goals in order to avoid interference while providing proper shielding.