Many radio devices adopt pre-certified radio modules (such as the ESP32 series, u-blox, Quectel, SIMCOM, Telit modules, etc.). For this reason, many applicants wonder whether the testing and certification costs can be reduced when applying for CE/RED, FCC, and ISED certifications for their finished/integrated products. This article will answer customers’ questions in detail.

Question 1: Can finished/integrated products directly use the test reports and certificates of the radio module?

Xinwei Reply: If the radio module is classified as a single modular device rather than a restricted module, the finished/integrated product may reference the radio test data of the radio module. Please note: Finished/integrated products cannot reference radio test data from restricted modules.

Question 2: How much testing cost can be saved for finished/integrated products incorporating pre-certified radio modules?

Xinwei Reply: For EU CE/RED certification, where the radio module is a single modular device, the finished/integrated product may reference approximately 60% of the module’s radio test data. Under this scenario, the finished/integrated product only needs to complete EMC (Electromagnetic Compatibility) + RSE (Radiated Spurious Emission) + RF Exposure (or SAR testing) + LVD/safety testing.

For FCC certification, the finished/integrated product only needs to undergo EMC testing (per FCC Part 15B). However, we still recommend that finished/integrated products also perform RSE (Radiated Spurious Emission) and RF Exposure testing.

Question 3: Given that the radio module integrated into the finished product already holds CE/RED/FCC certifications, why does the finished/integrated product still require RSE (Radiated Spurious Emission) testing?

Xinwei Reply: Module testing is performed on a standalone fixture, not under the conditions of your finished product’s enclosure, main board, power supply and cabling.

During the module manufacturer’s testing: the module is tested separately on a standard fixture with a designated antenna.

Once you solder the module onto your PCB, install it inside a plastic/metal enclosure, and connect it to your custom power cables and I/O lines:

• Coupling between the main PCB traces, digital circuits and Bluetooth RF will generate new spurious emissions

• The enclosure alters antenna radiation and resonance; spurious emissions that passed for the standalone module may rise after integration into the end product

• Power and signal cables can act as radiating antennas and introduce additional RF spurious emissions

These spurious emissions resulting from coupling in the finished/integrated product cannot be fully simulated during standalone module testing, and the module certificate does not cover such risks. EU CE/RED and FCC regulations do not have a statutory mechanism under which module certification grants a full exemption from end-product testing.

Question 4: What is SAR testing?

Xinwei Reply: SAR (Specific Absorption Rate) is a safety test to measure how much radio frequency energy from wireless devices is absorbed into human tissue. For portable products used close to the body (antenna ≤20cm from user), we need SAR test to meet FCC and EU RED RF exposure safety requirements. NFC/LF RFID do not need SAR (only EMF magnetic assessment). Module SAR reports cannot replace finished-product SAR evaluation, as the host hardware and enclosure will alter RF radiation characteristics.

Question 5: How to determine whether SAR testing is required for finished/integrated products?

Xinwei Reply: First, we need to determine whether the finished/integrated product is portable or handheld, and whether it is used within 20cm of the human body. Then, we also need to determine which wireless connectivity the finished/integrated product supports, such as Bluetooth, Wi-Fi, Zigbee, NFC, LoRa, RFID, GSM, WCDMA, LTE, 5G, NB-IoT, or LTE Cat M1, etc. 

SAR test requirement for portable body-worn devices is not defined by a fixed power number, calculated by FCC KDB447498 for US and EN 62479 for EU. 

・ FCC: any transmitter with time-averaged power ≤1mW gets unconditional exemption. Above 100MHz~6GHz, use formula with transmit power, frequency and antenna-to-body separation distance to judge if SAR test required. 

・ EU RED: EN62479 low-power exclusion assessment. If exceed exclusion threshold, SAR test per EN62209 is mandatory. 

・ NFC & RFID: near-field inductive system, EMF magnetic field assessment only, NO SAR. Cellular (GSM/WCDMA/LTE/NB-IoT/Cat.M1/5G sub6G) portable products normally require SAR test。

Email:Kobe@xinwei-test.com