Testing and Approval of Radio Modules in the European Union

In Part One of this article (published in the April issue of In Compliance Magazine), I provided an overview of the basic requirements for North America (the FCC for the U.S. and ISED for Canada) for radio modules and equipment which contain radio modules. So now pour away your cold coffee and brew yourself a nice hot cup of tea, as we journey across the Atlantic Ocean to the European Union (EU).

The EU’s Radio Equipment Directive (RED)

The EU has Directives, such as the Electromagnetic Compatibility (EMC) Directive and the Radio Equipment Directive (RED). These are trade-related Directives but there are technical essential requirements for meeting them.

Have you remembered the difference between “testing” and “approvals” that we discussed in Part 1 of this article? I do hope so.

Let us return to the world as viewed by the radio module manufacturer. I keep using the word “radio” and so we look to the RED. After much searching through the Directive, we realise there is no section addressing radio modules, nor is there a section addressing modular approvals. In fact, we realise there is no certification either!

Issuing a Declaration of Conformity

The sole approval route available in the RED is a Declaration of Conformity (DoC). The DoC applies to the final radio equipment, and the DoC is created (and signed) by the manufacturer of the final radio equipment, attesting to the product’s compliance with the RED’s essential requirements. The scope of those essential requirements include assessing the radio performance, EMC performance and product safety (including RF exposure) of any equipment that includes a radio function, transmitter or receiver.

Ok, so there are some exempt devices in the RED. But, to save some time, let’s assume you have a very normal consumer or commercial radio equipment that falls under the scope of the RED.

There is nothing in the RED specific for radio modules, or radios intended for installation into other equipment. Therefore, a radio module is just like any other piece of radio equipment in the EU, assuming it provides the radio function. I acknowledge that some devices are just chips or components for use inside a radio and I’m not talking about those here. I’m talking about a radio module, which would provide a radio function when you complete it with an antenna, a power supply and instructions for communication or determination. You can read the RED if you’re not sure.

In the EU, if the radio module manufacturer has defined their module as radio equipment within scope of the RED, they must apply the CE Mark as evidence of compliance with the essential requirements of the RED. Unlike North America, it is not an option in the EU to supply such a module without that evidence, even in cases where the market for a product is exclusively business-to-business.

The module manufacturer assesses the radio module, which most likely includes testing. Then, they create their DoC in accordance with the requirements of the RED and apply the CE Mark to their module. An EU Notified Body can issue a certificate called an EU Type Examination Certificate, but this is an examination certificate used by the manufacturer in support of their DoC and is not a certification or product approval.

In Part One of this article, we learned that North America
has transmitter performance and EMC emissions only, with RF exposure as the safety requirement. In the EU, however, we have radio transmitter performance, radio receiver performance, EMC emissions, EMC immunity, product safety and RF exposure. The radio module must be assessed by the module manufacturer for compliance with all of these requirements in the same way that any other radio equipment would be assessed. They cannot leave to the module installer any part of that assessment process.

There is No “Modular Approval” Route in the EU

There are no special assessment procedures exclusively for radio modules expected to be installed in other equipment, and there is no “EU modular approval” pathway. Instead, the RED’s requirements are intended to allow the module to be placed on the market as a radio equipment. There are no requirements that a module must have a dedicated antenna or voltage regulation, etc., and there are no specific requirements for radios expected to be installed into other equipment.

The RED states that radio equipment shall be assessed for its intended use and intended environment. This might seem quite simple for most products, but it’s not so simple for radio equipment that is intended to be installed into other products. In fact, module manufacturers often don’t know how their products will be used or the end products in which they might be installed.

For that reason, the most common testing approach used by radio module manufacturers is to test the module on a test jig or at the end of a length of cable. Then, the CE Mark signifies that the radio module is approved for use on that test jig or cable, and any other installation or use would not be permissible. The DoC documentation that accompanies the radio module should state the conditions under which the module has been found compliant with the RED requirements, enabling the installer to ascertain which antenna, test jig, temperature range, voltage range, software version, etc., were used in approving the module.

If the radio module has a Type Examination Certificate from a Notified Body, one would hope that that level of information would be on the certificate. In any case, such information should be available in the documents supplied to the installer of the radio module.

It is also important to remember that the CE Mark on the radio module does not guarantee that the final radio product will comply with all applicable requirements once that module has been installed into a host device. This is consistent with the fact that an FCC ID and ISED certification number do not guarantee that the final radio product will comply with the technical testing aspects of the FCC rules or ISED standards once that module has been installed.

I am not trying to say that a CE Mark on a radio module is a useless thing. In fact, radio module manufacturers put a lot of work into developing, testing and assessing their radio modules to help ensure that the market receives a quality, compliant radio device. A CE Mark on a radio module is a sign that the module has been assessed in accordance with the requirements of the RED and has passed the required tests. At the very least, the installer knows that the module should pass all required tests in at least one end use condition.

Requirements for Radio Module Integrators

Once again, let’s go back and look at the world from the point of view of the company installing that radio module into their host product. Again, you’ll face several difficulties and decisions.

As before, the manufacturer of the final product will take the radio module and install it into their device (the host), creating a new final radio product. Until this point, the host product may not have been a radio product at all, and had been assessed only in connection with the essential requirements of the EMC Directive and the Low Voltage Directive (LVD). But now, with the integration of a radio module, the host product falls under the scope of the RED, and EMC Directive and the LVD are no longer relevant since the RED has its own EMC and product safety requirements. So the manufacturer of the final radio product must now take full responsibility for the new radio equipment, creating their own DoC in accordance with RED requirements and applying the CE Mark to the host product.

You could say at this point that the radio module has effectively disappeared and no longer exists as a piece of equipment itself. It is now part of a larger piece of equipment. This applies not only to the things we typically imagine as modules, like a small device without any covers. It applies to any radio equipment (module or not) which has been permanently installed into another piece of equipment before that final product is placed on the market in the EU.

Since neither the radio module nor the final radio product is “certified,” there is no certification that can be transferred from the module to the host product. In North America, a module certification would still exist and remain valid after its installation in a host product. But that’s not the case in the EU. The radio module has the DoC issued by the module manufacturer, but the manufacturer of the final radio equipment must now assess their product, which includes the radio part, to verify compliance with the requirements of the RED and issue a new DoC.

Further, if the radio module manufacturer had previously obtained a Notified Body EU Type Examination Certificate, that certificate would apply only to the module and would not be transferable to the final radio product. If the final radio product requires a Notified Body EU Type Examination Certificate, then the manufacturer of the final radio product will need to obtain that.

The manufacturer of the final radio product is responsible for fully assessing their equipment to all the essential requirements of the RED, which typically means assessing their product against the requirements of all of the applicable standards, as well as any other issues that might have been identified in their risk assessment. And the final radio product will also require a full safety assessment. For example, if the final radio product is intended for use at distances of ≥20 cm or greater from a person or transmits at less than 20 mW, it is possible that the manufacturer of the final radio product would choose to adopt the RF exposure assessment from the radio module.

The final radio product would also need to be assessed in connection with EMC issues. Typically, the radio module would have been assessed for sitting on a test jig or at the end of a cable. So the existing EMC results would apply only if the final radio equipment is equivalent to the same conditions. If not, we can’t assume that the EMC testing of the radio module will be valid for the final radio product. And, most likely, the host product will have some other features or operating modes not associated with the operation of the radio module, which may fall under the scope of another standard with different EMC requirements.

(Again, I imagine myself writing my book titled “how to predict EMC results accurately enough to provide legal evidence” while sipping a Mai Tai in Waikiki.)

Although the final radio product must undergo a radio performance assessment, the installer may decide that some of those radio tests do not need to be fully repeated, in much the same way as we saw with the FCC and ISED requirements. As we saw in Part 1 of this article, the installation of a radio module into a final radio product could improve or worsen the radiated radio and EMC performance. In all likelihood, results from tests like duty cycle, frequency hopping, etc., would be unchanged if the module is installed correctly without any modification.

However, in test cases where the change of enclosure could affect performance, such as with EIRP, spurious emissions, receiver performance, etc., retesting should be considered. This can be especially important for products in which the radio’s antenna is inside the host equipment, since the addition of a new type of antenna can affect the radio’s performance. It’s also important in cases where the module has an RF pin and the antenna trace is part of the installer’s host equipment

Again, I have over simplified things for the purpose of getting you back to work quickly. I could, and regularly do, talk for hours or days on this subject.

Consequences for Non-Compliance

On the subject of legal responsibility for non-compliant products, everyone also wants to know which party will be in trouble if market surveillance in the EU finds a non-compliant device. In short, if market surveillance finds a radio module on the market and test it, and find it is non-compliant, the module manufacturer is in trouble. However, if market surveillance finds a final radio product on the market, tests it, and finds it is non-compliant, the manufacturer of that final radio product is the one on the hook.

Testing for Radio Module Integrators

I am often asked for guidance on how much testing is required on a final radio product with an integrated radio module. Specifically, must the installer now check all of the radio test cases like EIRP, spurious emissions, receiver performance, etc., even when the module was fully tested beforehand? Does the installer have to test every modulation mode, test three channels in every frequency band, and repeat every test?

I am sorry to say that there is no one answer that satisfactorily addresses every situation and retesting must be considered on a case-by-case basis. Even a manufacturer that installs different radio modules into similar models in a given product line will need to assess each one separately and may find a different approach is needed in each case.

It helps significantly if you have access to the radio module’s test reports. It also helps if you have expertise in reviewing test results, or if you know someone who can. But it’s not a big problem if you don’t.

In reality, I suspect that there are a few different approaches taking place around the world…

I suspect there are module installers who wish to minimise the amount of testing they do and, therefore, have EMC and radio experts on call to help them evaluate each new design. They could study the radio module’s test reports to identify the channel, mode and modulations which gave the worst-case measurement results. Then, they begin their testing of the final radio product, making some initial measurements of the channel and modulation which gave the highest test result, and then reviewing the new test results at each stage. If the test results look acceptable with comfortable compliance margins, they may then write a technical justification for why additional testing was not required and keep it on file. In the EU, this justification would be part of the risk assessment in the product’s technical documentation.

In such a scenario, the benefit is that the minimum amount of testing is performed and no unnecessary test time is wasted. The down side is that you have to employ someone who knows what they are doing and give them time to study the report, interpret the results, and then be prepared to go back to the test lab for more testing if the compliance margins look small or if it looks like another channel or mode should be tested. You also need a test lab who can help interpret the test results and that has the flexibility to extend the test session if the results look close to the limit.

Meanwhile, I suspect there are module installers who do not want to spend money on EMC and radio experts and don’t want to spent time looking over test reports to make justifications. Maybe their test lab has one booking available and getting a second booking later would prove difficult. Maybe the test is run by a technician using automated software, which is an efficient method but which may not support interpretations of partial testing.

In the end, those in this group might say “Just stick it in the lab and test everything.” They’ll spend more time and money at the lab, but they’ll spend less time and money in the office. In reality, it comes down to the balance between cost, time to market, and of course integrity.

Conclusion

Well, there we are. Somehow, I have used more than 6,000 words in this two-part article and yet have just begun to scratch the surface of this complicated but interesting topic. I have spent the last few years specialising in radio modules and their installation into host equipment, and I really could keep on writing more. But I suspect you have read enough. Your tea is cold and your cake is stale.

When I first became a TCB and Notified Body many years ago, most of the e-mails I received went like this: “I have a Bluetooth transmitter, please certify it for the FCC and review it as a Notified Body”.

Oh, how I long for those simpler times!

Now, the e-mails I receive go more like this: “I have a product, I installed pre-certified modules for Bluetooth, WiFi, and LTE. Each module is certified and has a CE Mark, so I don’t think I need your help as a certification body and I think I have done everything I need. But could you please check my homework?”

My role has changed as our industry has evolved to meet the needs of society and we work to live more (wirelessly) connected lives in the 2020s. I wonder what the next decade will bring?

If you would like further help with this topic, you know where to find me. And thanks for listening!