DELTA ready for emission measurements above 1 GHz

The internal clocks in modern electronic products continues to increase toward even higher frequencies, while emission requirements of EMC standards has not changed in many years and usually stop at 1 GHz.

The aim of emissions limits is to protect the frequency spectrum so we can use it for radio communications. Hence this new upcoming requirement for emission measurements above 1 GHz.

Since long, these requirement has exist in USA (FCC) and for radio products in ETSI standards, and now the same requirement  is starting to appear in European EMC product standards such as:

• EN 55022 / CISPR 22 (IT, Information Technology Equipment)
• EN 61000-6-3 and -4 (Generic emission standards)
• and in the future CISPR 32 (Multimedia equipment)

How high in frequency the measurement shall be performed to depends on the highest internal clock of the product as follows:

1 GHz if internal source <108 MHz,
2 GHz if internal source from 108 to 500 MHz
5 GHz if internal source 500 to 1000 MHz;
5 x source (up to 6 GHz) if internal source> 1 GHz

The emission measurements above 1 GHz is nothing new for DELTA. What complicates the measurements are the new requirements for validation of the test site in CISPR 16-1-4.

To meet the VSWR (Voltage Standing Wave Ratio) validation requirements of the CISPR 16-1-4 standard places great demands on the EMC-chamber performance and requires a special type of absorbers to be placed around the test object and the antenna, see Figure below.

Emission measurements below 1 GHz are still being performed with a reflecting ground plane, so there will be two different test set-up for a complete emission measurement.       

During a few summer weeks DELTA's EMC chamber-A in Västeras were upgraded, and is now one of the first to meet the new requirements for measuring 1 to 18 GHz. We can now help our customers meet the upcoming emission requirements.