Connected devices must combine regulatory compliance, EMC, radio performance and operational reliability. Testing makes it possible to check electromagnetic emissions, immunity to disturbances and wireless communication performance, in order to limit interference and malfunctions. Depending on the product and the technology used, various EMC, RF and ETSI requirements may apply. HEMERA RF supplies and integrates the instruments, antennas, shielding solutions and software needed for the EMC and radio qualification of connected devices.
EMC and radio: qualifying very different devices in multiple RF environments
The term IoT (Internet of Things) covers a very wide variety of equipment. A connected device may be a medical device worn by a patient, an industrial sensor, sports equipment, a tracking or location system, a household device or a terminal designed to transmit data to a network or an application.
Their size, operating conditions, power supplies, antennas and radio technologies can vary widely. This diversity is directly reflected in the frequencies used: some medical applications, for example, use bands around 400 MHz, while many devices use the 2.4 GHz band for technologies such as Bluetooth or Wi-Fi. Others use sub-GHz bands, cellular networks or higher frequencies.
IoT therefore has one distinctive feature: there is no universal IoT test or test bench. EMC and radio tests must be defined according to the device, its use, its radio technology, its frequencies, its environment and its target market.
HEMERA RF supports manufacturers and laboratories in defining and integrating EMC, RF and radio test setups, from the shielded enclosure for a small connected device to the anechoic chamber and automated radio characterisation system.
From medical devices to sports sensors: a very wide range of applications
Connected devices can be used in very different fields:
- healthcare and medical devices
- sport and physiological measurement
- home automation and smart buildings
- industry
- environmental sensors
- tracking and location
- security
- data transmission
- consumer electronics
- wearable devices.
This diversity matters from a regulatory point of view.
A connected medical device, a sports watch, an industrial sensor and a household device may use similar radio technology without being subject to exactly the same product requirements.
The applicable standard is therefore the result of a combination of factors:
type of product → use → radio technology → frequency band → environment → target market.
Very different needs, from start-ups to specialist laboratories
IoT diversity applies as much to the players developing the technologies as to the technologies themselves.
A connected device project may be led by a start-up, an SME, an industrial R&D department, a university, a research laboratory or a manufacturer that already has EMC and radio test facilities.
Not all of them necessarily have in-depth in-house expertise in EMC, RF or radio regulations. The initial need may therefore be expressed in very practical terms:
- test the range or radio behaviour of a prototype
- isolate a device from surrounding radio networks
- reproduce an RF environment in a controlled way
- check that a link remains operational in the presence of interference
- compare several antennas or integration configurations
- prepare a product for pre-qualification or compliance testing
- automate repetitive R&D tests
- equip an in-house laboratory step by step.
HEMERA RF can support these projects starting from the functional need, without the customer having to define the full test setup architecture beforehand.
Analysis then translates this need into technical parameters: frequencies, radio technologies, levels, device dimensions, shielded environment, instrumentation, antennas, interfaces, monitoring and automation.
Depending on the objective, the solution can range from a compact shielded enclosure fitted with the necessary interfaces to an automated installation combining an anechoic chamber, RF instrumentation, antennas, positioning systems and control software.
Start from the use case before talking EMC or RF
For a user who is not an EMC or radio specialist, the need can first be expressed as simple questions:
Does my device communicate correctly?
→ radio characterisation and performance.
Is it disturbed by other equipment or radio signals?
→ immunity and radio coexistence.
Does it disturb its own environment?
→ electromagnetic emissions.
Does its antenna work properly once integrated into the product?
→ radiated characterisation and OTA (Over The Air) measurements.
How can I carry out my tests without interference from Wi-Fi, Bluetooth or surrounding radio networks?
→ shielded enclosure, shielded box or suitable chamber.
How can I check that my device really keeps performing its function during the test?
→ monitoring of communication, transmitted data and functional behaviour.
This approach starts from the device's actual function before determining the EMC and RF resources required.
Support matched to the project's maturity
Needs also evolve as the product matures:
Prototype → characterisation → development → pre-qualification → qualification → production
At prototype stage, the aim may simply be to understand how an antenna or radio link behaves. Later on, it may become necessary to repeat tests, compare different product versions, prepare for qualification or automate checks.
A setup originally intended for R&D may therefore need to evolve with the project. Where relevant, its architecture can be designed to allow new frequencies, radio technologies, instruments, interfaces or monitoring functions to be added.
This scalability is particularly important for start-ups, universities, research laboratories and R&D teams, whose future needs are not always fully defined when they acquire their first test setup.
From functional need to test solution
You do not need to master EMC or RF instrumentation to define an initial need.
HEMERA RF can start from the device, how it works, its environment and what the customer wants to measure or verify, then gradually translate this need into a test architecture:
functional need → phenomena to characterise → frequencies and levels → test environment → instrumentation → antennas and interfaces → monitoring → automation.
This approach makes it possible to propose a setup proportionate to the need, from a compact R&D solution to a complete laboratory installation, without imposing a standard architecture on applications that are, by nature, very different.
From 400 MHz to several GHz: very different radio environments
IoT cannot be tied to a single frequency band.
Some medical applications, for example, use bands around 400 MHz, notably in the 401–406 MHz range, depending on the applications and regulatory frameworks concerned.
Other devices use sub-GHz bands, particularly for applications requiring long range or low power consumption.
The 2.4 GHz band is very widely used by technologies such as Bluetooth, Bluetooth Low Energy (BLE) and Wi-Fi.
Other applications use cellular networks or different frequency bands depending on their technology and market.
This diversity has a direct impact on the test setup. The antennas, generators, analysers, couplers, cables, RF components and shielded environments required are not necessarily the same from one application to another.
The test setup must therefore be sized according to the frequencies actually used and the performance to be characterised.
EMC and radio: two complementary issues
A connected device is both an electronic device and a communicating device.
Its qualification must therefore take several dimensions into account.
EMC emissions: what the device generates
The equipment must not produce electromagnetic disturbances that are incompatible with its environment.
Tests may in particular cover the conducted and radiated emissions generated by:
- power supplies and converters
- digital circuits
- clocks
- displays
- processors
- interfaces and cabling
- radio circuits.
EMC immunity: what the device must withstand
The device must also continue to behave as intended when subjected to electromagnetic disturbances.
Depending on its environment and the applicable standards, various phenomena may be considered: RF fields, conducted disturbances, transients or ESD (electrostatic discharge).
Radio: transmitting and receiving correctly
Finally, a connected device must perform its radio function.
Depending on the technology and the standard, tests may characterise, among other things:
- transmit power
- spectral behaviour
- frequencies used
- unwanted emissions
- receiver sensitivity and behaviour
- link quality
- radiated performance.
A product may therefore meet certain EMC requirements while delivering insufficient radio performance, or vice versa.
Combining EMC, RF and radio expertise is particularly important in IoT.
RED and ETSI: the European framework for radio equipment
For many devices that include a radio function and are marketed in the European Union, the RED (Radio Equipment Directive, Directive 2014/53/EU) is an essential regulatory framework.
As in other sectors, a distinction must be made between the regulatory framework and the technical standards used to demonstrate compliance with the applicable requirements.
The work of ETSI (European Telecommunications Standards Institute) plays an important role in this field.
Depending on the technology and frequencies used, different families of standards may apply. Examples include:
- ETSI EN 300 328 for certain wideband equipment operating in the 2.4 GHz band
- ETSI EN 301 893 for certain RLAN applications in the 5 GHz bands
- the ETSI EN 301 489 family for various EMC aspects of radio equipment.
There is, however, no single “IoT standard”.
The applicable standard and edition must be determined according to the radio technology, the band used, the product, its use and the target market.
Requirements that sometimes go beyond radio regulations
The radio function must not be considered in isolation.
Depending on the type of product, other standards may apply in addition to radio and EMC requirements.
A connected medical device, for example, may be subject to medical device-specific requirements, while an industrial or household device may fall under different product standards.
Two devices that both use a 2.4 GHz link therefore do not necessarily require the same qualification campaign.
This diversity explains why needs analysis must come before the choice of test setup.
From standard to actual test: an implementation that can be complex
In IoT, the challenge lies not only in identifying a standard.
The diversity of products can make interpreting test requirements and putting them into practice particularly complex.
In particular, it is necessary to determine:
- the representative configuration of the device
- its operating modes
- the radio channel or frequency to be used
- the transmit power
- its orientation
- the antenna position
- the data to be transmitted
- the interfaces to be maintained
- the peripherals required
- the criteria for detecting degradation
- the control and monitoring method.
Designing the test setup therefore means turning a regulatory or normative requirement into a reproducible physical, RF and software configuration.
Anechoic chamber or shielded enclosure?
The wide range of sizes is another distinctive feature of IoT.
A device measuring a few centimetres and a large connected device do not necessarily require the same test environment.
Anechoic or semi-anechoic chamber
A chamber provides a controlled electromagnetic environment for radiated measurements and can accommodate devices of various sizes.
It can include:
- RF absorbers
- measurement antennas
- positioning systems
- RF instrumentation
- feedthroughs and interfaces
- automation.
Shielded enclosure or shielded box
For small devices, a shielded enclosure or shielded box can be a more compact solution.
Its role is in particular to isolate the device from the external radio environment, and vice versa.
Depending on the application, the enclosure can include:
- RF absorbers
- internal antennas
- filtered feedthroughs
- RF connections
- power supply
- communication interfaces
- EUT control devices.
Adding absorbers also provides better control of reflections inside the enclosure when the test requires it.
The choice between a chamber and an enclosure therefore depends not only on budget or available space: it depends on the type of measurement, the frequency, the size of the device and the required performance.
Device size determines the test setup
IoT devices can vary enormously in size.
Sizing the setup must in particular take into account:
- EUT dimensions
- frequency
- measurement distance
- test volume
- antenna characteristics
- required electromagnetic isolation
- RF power
- interfaces needed for the device to operate
- monitoring
- positioning constraints.
This analysis avoids oversizing an installation for a small device or, conversely, choosing a compact enclosure that cannot correctly reproduce the required measurement conditions.
The integrated antenna: an essential part of the connected device
In many IoT devices, the antenna is integrated directly into the product.
Its performance can be affected by:
- the housing
- the printed circuit board
- the battery
- nearby components
- the position of the device
- its orientation
- its immediate environment
- the human body in the case of a wearable device.
The performance of the radio module alone is therefore not necessarily enough to characterise the performance of the final product.
A well-designed module may behave differently once integrated into its housing and combined with its final antenna.
This naturally leads to radiated measurements.
OTA: characterising the device in its real configuration
OTA (Over The Air) refers to radiated measurements made without a direct RF connection between the measuring instrument and the equipment's RF port for the quantity being measured.
This approach characterises the behaviour of the complete assembly:
RF electronics + antenna + mechanical integration + device environment.
Depending on the application, OTA tests may require a suitable chamber or enclosure, measurement antennas, controlled EUT positioning and RF equipment to generate or measure signals.
The aim is then no longer just to characterise a radio module, but the connected product in a configuration representative of its use.
Radio coexistence: several systems in the same environment
A connected device rarely operates in a completely clear radio environment.
The 2.4 GHz band is a good example: different technologies and many devices may operate in it simultaneously.
The question then becomes:
does the device continue to perform its function when another RF signal is present in its environment?
Coexistence studies may require the controlled generation of:
- wanted signals
- interfering signals
- different RF levels
- different channels
- different spectrum occupancy scenarios.
The test setup can then combine RF or vector signal generators, signal analysers, antennas, couplers, shielded enclosures or chambers, and automation software.
This approach makes it possible to create reproducible RF scenarios rather than relying on an external radio environment that is difficult to control.
Monitoring: checking that the device really performs its function
As in the automotive sector, an immunity or coexistence test is not just about checking that the EUT remains powered.
An IoT device may continue to operate while no longer correctly performing its communication function.
Depending on the application, monitoring may therefore cover:
- link establishment
- connection maintenance
- data transmitted and received
- packet loss
- transmission errors
- throughput
- latency, where it is a relevant criterion
- link level or quality, where this information is available
- disconnection
- reconnection after a disturbance
- operation of the associated application
- consistency of the transmitted data.
For example, a sensor may continue to measure a quantity but stop transmitting it. Conversely, a link may remain established while the data becomes incorrect.
The functional criterion must therefore be defined according to the device's actual use.
Automating to reproduce RF scenarios
The multiplicity of frequencies, channels, levels and operating modes makes automation particularly worthwhile for IoT testing.
An architecture can be organised along the following lines:
RF generation → controlled environment → EUT → link and function monitoring → acquisition → results analysis.
The software can control various instruments, change frequencies and levels, run test scenarios and synchronise measurements with the device's behaviour.
This automation helps improve the repeatability, traceability and usability of test results.
From need to IoT test setup
Defining a test setup therefore starts with an overall analysis:
device → use → radio technology → frequencies → market → standards → tests → performance → monitoring.
HEMERA RF can then size and integrate, as required:
- anechoic or semi-anechoic chambers
- shielded boxes and shielded enclosures
- RF absorbers
- antennas
- RF and microwave generators
- vector signal generators
- spectrum or signal analysers
- EMI receivers
- amplifiers
- power meters and power sensors
- couplers and RF components
- positioning systems
- filtered interfaces
- monitoring systems
- control and automation software.
The final configuration can therefore vary considerably from one application to another.
The HEMERA RF approach to IoT projects
In IoT, the challenge rarely lies in selecting a single instrument. It lies rather in building a coherent test environment around a device, a radio technology and a qualification objective.
HEMERA RF acts as general contractor and multi-brand integrator, from the technical qualification of the need through to commissioning of the test setup.
This approach can cover:
- requirements analysis
- definition of the test architecture
- choice between a chamber and a compact enclosure
- RF sizing
- selection of antennas and instruments
- sourcing of specialist manufacturers
- integration of EUT interfaces
- development or integration of software drivers
- automation
- functional monitoring
- commissioning
- metrology and calibration management.
The multi-brand approach is particularly well suited to IoT. A single installation may require a shielded enclosure, absorbers, a specialist antenna, an RF generator, an analyser, microwave components and software from different manufacturers.
The integrator's role is then to select the relevant technologies and make them work together as a single, coherent test system.
An approach suited to the diversity of IoT
From medical devices operating around 400 MHz to sensors or terminals communicating at 2.4 GHz or on other bands, IoT applications vary enormously in size, technology, environment and regulatory constraints.
This diversity rules out a one-size-fits-all answer.
The performance of an IoT test setup depends on its ability to reproduce the relevant RF environment, isolate the phenomena to be measured, control the device properly and verify its actual function during the test.
Drawing on its expertise in EMC, RF and microwave, its multi-brand approach and its ability to integrate instrumentation, shielded environments, antennas, software and monitoring, HEMERA RF can design tailored, automated and scalable test setups, from compact enclosures to complete laboratory installations.
There is no universal IoT test bench: the test setup must be built around the device, its application and its radio environment.