Book about Wireless IoT Design

Today I am introducing the intro for my new book "Wireless IoT Design". With over 30 years of experience in wireless technology and hundreds of wireless projects over the years, I have seen many mistakes in the design of wireless IoT devices. Several companies had to cancel their projects and some companies disappeared from the market because there was no rescue for the wrongly designed devices. Investors have dropped out. With my book on "Wireless IoT Design", I would like to make a contribution and give useful tips to developers with ideas for wireless IoT devices to achieve the desired goal or perhaps not to start the development in the first place. An IoT device that cannot be finished because of physics should not be started at all.

Intro to "Wireless IoT Design" Book

A wireless IoT device often requires far more preliminary planning than a classic electronic device without wireless technology. This book is a guide based on the experience of hundreds of projects over the last 20 years with wireless technology and antennas. It used to be called M2M and now it is called wireless IoT. There is no difference in the mindset for planning the device. IoT and M2M use radio modules/ radio IC and antennas.

Let's take a temperature sensor as an example. As long as this sensor measures and displays the temperature, the regulations for an electrical device apply there for the CE declaration. Sometimes there are differences in the regulations for consumer devices and industrial devices. If the sensor contains a battery, the regulations for batteries also apply. The moment a wireless link is added to the sensor, the temperature sensor becomes a radio device. Depending on the selected radio technology or frequency range, different regulations apply in Europe or the USA. In Japan, Korea, Australia and other countries, completely different regulations apply. Bluetooth is in the same frequency range worldwide, but still the regulations for approval are different in Europe and other regions. The modulations and access procedures for cellular radio technologies are often the same worldwide, but the frequency ranges and regional regulations are also unequal. The repeatedly cited LPWAN technology LoRaWAN is supposedly available worldwide. On second glance, LoRaWAN EU is not the same as LoRaWAN US. The access procedure is the same, but the permitted maximum spreading factors and times in the channel assignment are unequal in Europe and the USA.

Our wireless temperature sensor could now use Bluetooth, Wifi, ZigBee, Thread, LoRaWAN, Mioty, NB-IoT, LTE-M, LTE, 5G NR. An IoT gateway can be a combination of the wireless technologies mentioned or the many other wireless technologies not mentioned. If a tracking or telematics device is planned, then satellite positioning via GNSS is generally added.

All wireless IoT devices have in common that they use antennas. The choice of antenna and the right place to install an integrated antenna affects the range, the battery life and the chance of approval. An incorrectly selected antenna, an incorrect installation location or errors in the layout will most certainly lead to problems in the EMC measurements for approval. Such an error then leads to a wireless IoT device offering too little range or short runtime on battery or generating too much spurious radiation when measuring harmonics during approval, and the desired radio approval cannot be granted.

Unfortunately, poorly designed circuits can often no longer be improved. The external consultant called in can often only recommend replacing the circuit board or the antennas completely. If the housing of the IoT device is large enough, this will lead to the desired result. But if the housing is too small for the desired frequency range or frequency bandwidth, or if the installation of the necessary antennas is not possible, even the housing must be replaced. Then not much remains of the originally planned wireless IoT device.

The project management of a wireless IoT device is much more complex than for a classic device without radio technology. The many different regulations overwhelm the project managers and hardware developers. If, however, the necessary more elaborate planning is dispensed with due to a lack of knowledge, time or budget, this often leads to failure. Follow-up costs are incurred or it leads to a loss of confidence on the part of the customer or, in the worst case, it leads to the project being aborted because the desired IoT device cannot be built in the planned form at all.

This book has been limited in the selection of topics. Since the wrong choice or faulty integration of the antenna very often leads to a radio approval not being granted, there is a detailed chapter on integrated antennas. This ranges from self-made PCB antennas, chip antennas, patch antennas and many types of antennas more. How to integrate them into the circuit and measure them is explained in the chapter Vector Network Analyser (VNA). The explained measurement exercises introduce the reader step by step to the complex topic of VNA. Free software is then used to determine the matching networks. The many practical examples with integrated antennas show many good solutions. In addition, there are various bad examples. We can learn from the mistakes of other hardware developers. Often you can only avoid the mistake if you know that the mistake exists in the beginning. The special features of the layout of circuit boards with radio modules and antennas are also discussed.?The annoying topic of rules and regulations is also addressed.

I hope you enjoy reading and learning.

End of intro.

?"Wireless IoT Design" is the current working title of the book. Eventually, the book will get another name. But the focus is clear. The book will show a lot of practical measurement exercises on antennas and VNA, which the reader can follow. I will demonstrate it in the book and the reader will do it. Self-built PCB antennas and also chip antennas are used. If you have built and measured a simple PCB antenna yourself, you will understand the often quite complex chip antennas better.

In addition, there are many examples with errors. I see the mistake at first sight. The HW developer without experience with radio and antenna does not see it. This chapter can be extended at will later on. The more examples I include, the more the readers will learn.

The cheapest solution is definitely to call in a neutral external consultant and pay for the advice there. The hours of work are much cheaper than any redesign.

Chapter Curiosities

I don't know yet whether I will include this chapter. I have actually used companies that glued a flexible antenna with cable for Bluetooth to the inside of the metal case. Metal is conductive. That's why the radio wave passes through the metal housing, the customer thought.

The "sandwich" of the cover of the radio module, the PCB antenna with cable and the battery on top was also extreme. A PCB antenna wrapped in metal. On top of that, the metal of the radio module and the battery are directly connected to ground.

Apart from the extreme curiosities, there are of course others that don't sound quite so extreme, but still lead to non-functioning or harmonic harmonics during radio certification.

Non-binding pre-orders for the estimated 200 papes DIN A4 in PDF are welcome at harald.naumann(at)lte-modem.com. Furthermore, I offer training on the VNA via video call and e-mail. The MegiQ VNA is perfectly suited for this.

Imprint

• Harald Naumann, Ludwig-Kaufholz-Weg 4, 31535 Neustadt, Germany
• Contact: harald.naumann (at) lte-modem.com, Phone: +49-5032 801 9985, Mobile:+49-152-33877687