Unleash the potential of the IoT: DIY antennas for round devices
Harald Naumann
As the winner of the 5G NTN Antenna Award , I am happy to inform you about my 0 USD antenna concept and more – contact me!
Round IoT devices require round antenna shaped. Dive into real-world examples, from water meters to order buttons, where homemade antennas shine. Get ready to redefine your IoT projects.
With custom antennas, you have the freedom to keep costs down without compromising performance. Best of all, these antennas have no end-of-life, which means they are durable and future-proof.
The low cost of making your own antennas can mean significant savings for your IoT projects. Instead of buying expensive off-the-shelf antennas, you can use low-cost materials and still achieve superior performance. This is especially important if you are deploying IoT systems on a large scale.
But it's not all about budget. Self-made antennas also offer impressive performance. You can tailor the design to your specific needs to maximise signal strength and range. This adaptability is the key to a reliable IoT network.
What's more, self-built antennas are not a one-off investment. They are durable and will not suddenly become obsolete. You can always adapt the antennas to new requirements without having to buy expensive spare parts or replace all your hardware.
This cost-effective, powerful and future-proof solution not only advances your IoT projects, but also keeps you in control of your wireless communications. Create a no-compromise connection with homemade antennas and take your IoT innovations to the next level. Get ready to shape the future of wireless!
What IoT devices need a round PCB?
Water meters: Water meters very often come in round housings. In my basement, there is a water meter with 868 Mhz wireless technology from Diehl. The diameter is almost 70 mm. 433, 868 and 915 MHz are common unlicensed frequency ranges for water meters.
Gillette order button: The Gillette order button [2] was rectangular in the prototype. The other versions were also square. The production version was also rectangular. When everything was ready, Procter and Gamble wanted a round version. So the PCB was changed and 22000 units were made with a round PCB. The antenna in the order button works on the cellular bands 20, 8 and 3. The diameter was 70 mm.
LoRaWAN sensor: In the study "Low-cost PCB antenna design for wireless IoT"[1] you can find a LoRa sensor on a round PCB. Since 868 and 915 MHz are required for the USA, a switchable antenna was needed. The PCB was 70mm in diameter.
Bluetooth buttons and sensors: Such IoT devices are very often built with round PCBs. A 20mm diameter CR2032 button cell is often used. The button cell means that PCBs with a diameter of about 30 mm are used. The frequency is about 2480 MHz.
The size of the PCB depends on the centre frequency and the bandwidth required. This law was discovered by Chu in 1946.
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Round PCB in a water meter with self-made antennas: The pictures show a PCB in a water meter, top view and side view. The other components, the case and the water pipe have been made invisible in the simulation so that the PCB with the antenna is visible. It can be seen that the radiation is almost omnidirectional. You can also see that it is not just the antenna that is radiating, but the whole PCB. The PCB has a diameter of 65 to 70 mm. This is already small compared to the wavelength of the 868 MHz frequency. This results in almost omnidirectional radiation.
IoT device with 90 mm diameter: The task is to place three antennas for 915, 2400 and 1576 MHz on a 90 mm diameter. The 915 MHz frequency range is used by LoRaWAN, MIOTY, NeoMesh, Sigfox and many others. 2400 MHz is used by Bluetooth, WiFi, ZigBee and more. At 1575 to 1610 MHz we find various GNSS. The 3 antennas can be placed together in a common free space. There is no need to buy expensive chip antennas. The common free space for the antennas creates a lot of space for the three radio modules, the MCU and the sensors.
In the world of IoT, the round PCB and self-construction of antennas is the key to cost efficiency and optimised performance. Why buy expensive when you can innovate? Enquiries for low-cost antenna designs are welcome at harald.naumann (at) lte-modem.com ??????
References
[1] Low-cost PCB antenna design for wireless IoT
[2] The journey to develop the Gillette order button
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