How to Level-Up Your IoT Devices with Solid RF Design

If your Cloud-enabled product isn’t multi-modal, multi-vendor, and multi-protocol, it’s not achieving peak connectivity performance. To get there, you need proper RF design.

26 October 2021

It shouldn’t be news to anyone at this point that we’re living in an Internet of Things (IoT) world. Cloud-enabled devices are almost an expectation at this point in every industry. The Cloud has opened new doors to faster and more efficient design, development, and logistics across verticals. But to take advantage of the Cloud’s full capabilities, a device has to be able to connect to it properly; that is, it must connect reliably in multi-modal, multi-vendor and multi-protocol environments. That level of connectivity comes down to the RF signal chain. Every link of the chain should be optimized to provide the highest level of functionality and efficiency in as cost-effective a manner as possible.

In this blog, we’ll break down what it means to have “proper” RF design and some of the common challenges of design and integration.

The 3 Keys to Successful RF Design

In the context of IoT devices, ideal RF design means optimal system integration. The system must obviously provide the RF functionality required for the application, but just as crucially it must be able to handle the complexities of today’s Cloud-enabled products.

To ensure multifunctional, multimodal wireless solutions, there are three aspects of RF design that must be addressed. They are as follows:

  1. Power
    Every operational aspect of the system is driven by electricity, making energy budget a critical consideration. This characteristic will impact battery life, thermal management and the primary function of the RF system— converting power into a transmission.

  2. The Product Itself and Functionality Integration
    In order to achieve marketplace success today, a product needs to easily integrate all essential and in-demand operational technologies. The fastest or most sophisticated wireless connectivity is only secondary if the data and functions being transmitted are impractical or underwhelming for the user.

  3. Infrastructure
    This is the biggest of the three: the infrastructure required to support all these products and their functionalities. Systems and software must be properly integrated to maintain performance in the complex wireless ecosystem, which comprises more personal electronic devices and use of the electric spectrum than ever before.

Protocol Selection

Effective RF design means accounting for the complexity of the multimodal Cloud environment in addition to selecting the right wireless protocols for the solution itself.

For example, environmental monitoring over the area of a facility campus or location reporting in fleet management are useful functionalities which do not require a huge amount of bandwidth. Their requirements are best met by a low-bandwidth, long-range RF protocol like LoRa rather than the more expensive 5G, despite its current popularity. A good rule to follow in fully addressing your application’s RF requirements is to select a high-bandwidth protocol like 5G or WiFi for software-over-the-air downloads and updates and a low-bandwidth connection for status reports and commands. This way, functionality is maximized while data and power loads are minimized when not needed for system operation. The extensive list of solutions available can seem overwhelming (5G, LoRa, Bluetooth, WIFI, GPS, Zigbee and so on) but most current RF-enabled microcontrollers and RFICs are capable of multimodal operation.

Device Integration and Software Management

Basic RF functionality is already enough to think about. But the sensor suites and infotainment systems of many modern advanced electronics require additional RF capabilities that come with their own integration challenges. The same antennas and/or software-defined radio subsystem could serve several purposes, like vehicle-to-everything (V2X) communications in smart-traffic systems which also enable passengers to stream music from their phones to the car’s stereo system. In a properly designed RF system, assets will complement one another’s functionality without creating unnecessary duplication (ie: not required for redundancy or safety reasons.)

We see this in many telematics applications. GPS, transceiver communications and driver monitoring systems are integrated with additional hardware and software functionality, creating an optimized solution using the least number of components possible. With a concept like sensor fusion that is not a direct technology, the design team can get creative. With compatible RF infrastructure, an RF sensor suite could perform vehicle communications functionality in conjunction with its V2X system, where the vehicle “sees” people by detecting their personal device.

Benefits of Fewer Hardware Requirements

Reducing the need for hardware should also be an RF design goal, as it comes with several significant benefits. That means taking advantage of areas where RF hardware capability can be replaced by software-defined radio systems. One example might be using one RF filter module instead of 50 discrete components.

Resulting benefits include:

  • Reduction of board size/overall product size
  • Reduction of packaging requirements and costs
  • Smaller, more efficient power electronics
  • Highly integrated microcontrollers and RFICs

When combined with the latest antenna designs, these products are able to be more connected, multifunctional, and cost-effective.

Important Application Considerations

A modern RF systems integrator must consider multiple factors to create a truly optimized solution, namely defining the application space. Just a few of the important questions to consider:

  • Where will the product be deployed?
    Location often determines the environment the system may experience, impacting foreign-object contamination, moisture ingress and thermal management.

    As a note, products are often deployed in unexpected locations, like an indoor device used outdoors or a product placed too close to an exhaust vent. It’s wise to err on the side of caution with regards to harsh environment resistance, as budget allows.

  • How much access will users have?
    User error is one of the most common causes of product failure, so it’s essential to take access into account. The means of user interface will determine factors like system ruggedness (display or no display) or cable interfaces (holes in the package) which impact product utility.

    Advanced wireless devices involve several areas of RF management: signal for the Cloud, power for wireless charging, sensor fusion for gesture capture and facial recognition and more. The design can be simplified by recognizing all areas of power and signal management overlap.

  • Does it have to connect to other devices, the facility mainframe or the Cloud?
    This is where the vastly important antenna(s) comes in, especially for a system that must interface to the Cloud. The desired system functionality will determine whether RF subsystems can share one antenna, or whether they will each need their own in order to optimize antenna design for desired wavelength and minimize coupling problems.

The need for proper antenna design cannot be overstated. An antenna must be able to receive the necessary frequencies and do so in an optimal manner. Coupling mismatch between the electronics and the antenna will reduce performance, increase thermal energy waste and drain power unnecessarily. In addition, poor RF performance will directly impact user experience. In addition to harsh environment resistance, proper antenna selection should also take into account cosmetic and/or aerodynamic concerns in solutions like autonomous vehicles and consumer robotics. Testing the antenna is essential; only thorough testing can confirm your antenna design’s optimal performance.

For these reasons, careful vendor selection is as important as component selection. A good antenna vendor will not only have the expertise to aid in your design, it will also have the test and evaluation facilities to test them effectively. The new world of wireless connectivity requires high-level awareness of how multiple subsystems and protocols work together so you can design an optimal solution. An experienced electronics manufacturing services (EMS) partner can provide design and testing services, including the RF front-end in these systems. PCI has more than 30 years of EMS experience focused on consumer goods, industrial, automotive, and medical devices, as well as in Printed Circuit Board Assembly (PCBA) and box builds.

Our Lean Six Sigma manufacturing expertise enables us to customize our manufacturing line to meet our partners’ requirements. Contact PCI today to learn more about our capabilities.

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