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Werlatone has introduced a comprehensive range of directional couplers and combiners, specifically engineered to excel in the harsh conditions of EMC/EMI Testing. These advanced solutions, known for their high power capability and exceptional tolerance to mismatches, are widely integrated into EMC amplifiers worldwide. 

Additionally, they find extensive application in EMC test chambers and various test bench measurement setups, ensuring reliable and accurate results in critical testing environments.

Directional couplers serve as versatile tools for measuring RF/microwave power levels. By sampling a small portion of the signal power through a transmission line, they allow for accurate measurements with minimal disruption to the main line. When combined with RF/microwave test instruments like spectrum analyzers or EMI receivers, these couplers play a crucial role in understanding the electromagnetic compatibility (EMC) of new electronic designs and identifying potential excess electromagnetic interference (EMI). Many electronic products must undergo rigorous EMC/EMI compliance testing to meet market requirements. To prepare for such testing, developers of high-frequency components and systems often employ EMC/EMI pre-compliance testing, where directional and bidirectional couplers offer simplified and effective solutions.

Werlatone Directional Couplers are frequently installed as accessories to EMC test systems to enable accurate supplemental power monitoring. 

A directional coupler basically consists of two parallel transmission lines. The primary line carries the majority of the input power to the output port, while the secondary line couples a precise fraction of the total power to a coupled port, following a predetermined coupling ratio like 10, 20, or 30 dB. This setup offers access to a small portion of the forward signal power, which proves valuable for transmitter monitoring and control purposes. It also facilitates power measurement when applying signals to a test antenna during electromagnetic susceptibility testing of a device under test (DUT). This enables a deeper understanding of the DUT's behavior in scenarios with multiple concurrent signals. On the other hand, a bidirectional coupler can provide coupled energy in both the forward and reverse (reflected) directions.

EMC/EMI testing of a device under test (DUT) is constrained by the performance characteristics set by the DUT itself, including factors like frequency range and maximum input power. To ensure standardized and accurate EMC/EMI measurements, national and international standards bodies like the FCC in the United States and CISPR in Europe establish specific performance levels and measurement bandwidths for test equipment. Adhering to these defined standards guarantees consistent and reliable EMC/EMI testing results.

Werlatone Directional Couplers are ideal for EMC test bench applications during the design and development of EMC amplifiers and test systems. 

When assessing electronic products for electromagnetic interference (EMI), it is crucial to account for broad frequency limits. While a product's fundamental frequency range may serve as its defining characteristic, it is essential to recognize that higher power levels can introduce second-harmonic (×2) and third-harmonic (×3) components of those fundamental frequencies. Consequently, EMI power measurements for products operating within a fundamental frequency range up to 6 GHz may need to extend up to 18 GHz. This expanded frequency range ensures thorough and accurate evaluation of EMI effects across various harmonic components.

To ensure effective EMC/EMI pre-compliance measurements, the selection of a directional coupler must align with the specific requirements of the test setup. Various performance parameters define directional and bidirectional couplers, such as frequency range, maximum input power, coupling factor, and directivity. In an EMC/EMI pre-compliance test setup, signal power is typically generated by a signal generator, often amplified by low-noise or power amplifiers, and directed towards test antennas. Although the signal generator may have a broader frequency range than the device under test (DUT), it is important to consider the impact of second and third-harmonic frequencies when determining the necessary frequency range for a coupler feeding a spectrum analyzer or EMC/EMI test receiver. By carefully matching the coupler's performance parameters with the specific requirements of the setup, accurate and reliable EMC/EMI pre-compliance measurements can be achieved.

Click here to learn more about Werlatone's EMC Testing Products.