Product development for wireless and electronics encounters a number of RF/EMI Shielding challenges for products and parts of all sizes and applications.
RF isolation is key to test and calibrate the product and components at various stages of development, free from RF interference. RF interference comes from external sources like cell towers or airports, and internally from RF emitting prototypes in the lab.
RF / EMI compliance testing is a key step in product development. This testing is designed for two major purposes, RF susceptibility and RF radiated emissions. RF susceptibility testing is important to assure the product is fully functional in actual use when subjected to RF signals of varying strengths in various locations and situations in the real world. Testing for radiated emissions is key as the FCC requires all products to be properly shielded and certified by independent labs to prove that they do not transmit radiated emissions.
Pre-scan testing of the product in the R&D lab is critical prior to sending it out for independent certification testing. This pre-scan testing should be performed at various development stages to allow quick corrective action. This is critical to maintain product launch schedules and reduce redesign costs, which escalate as the product progresses through development.
Pre-scan testing can also avoid significant costs and delays by preventing the product from failing during external compliance testing. This will save retesting costs, logistics back and forth to the independent test lab, and expediting costs to maintain launch schedules.
RF isolation is critical in pre-scan testing for accuracy and to assure the testing process itself does not emit signals in violation of FCC guidelines. RF isolation can be achieved in the lab with RF shielded boxes, pouches, or tabletop enclosures. Curtains between racks of equipment are also common. Tests of large products are done in shielded rooms or very large RF shielded enclosures.
RF shielded enclosures can be permanent hard-walled or made from lightweight high attenuation fabrics. RF fabric boxes, pouches, tabletop enclosures, and tents allow portability and collapsibility for use in the field or to save space in the lab.
Hard-walled rooms with non-reflective foam and tiles can do a myriad of testing. High attenuation tents can range from room-sized to hangers for vehicles and aircraft. These tent systems can also use reflectivity dampening foam and are fitted with sophisticated RF filtering systems and air conditioning.
The choice of an RF isolation solution must consider the nature of the testing required and the total cost of ownership, including the cost of the enclosure, the cost of the space utilized, the cost of external testing, and the cost of moving for reuse. Major permanent product development facilities may be best served by a common multi-use RF shielded chamber. With shorter product development times, a portable, storable, reusable fabric solution may be an option to consider.