IEC 61000-4-21:20 11考虑了电气和/或电子设备的抗扰度和有意或无意排放测试，以及混响室中屏蔽有效性的测试。它建立了执行此类测试所需的测试程序。仅考虑辐射现象。IEC 61000-4-21:20 11的目的是为使用混响室评估电气和电子设备在射频电磁场作用下的性能以及确定电气和电子设备发出的射频辐射水平建立通用参考。IEC 61000-4-21:20 11不打算指定应用于特定设备或系统的测试。其主要目的是为IEC的所有相关产品委员会提供一般的基本参考。产品委员会应与CISPR协商选择排放限值和测试方法。产品委员会仍负责适当选择适用于其设备的抗扰度试验和抗扰度试验限值。可以使用其他方法，诸如IEC 61000-4-3、CISPR 16-2-3和CISPR 16-2-4中所涵盖的那些。这第二版取消并取代了2003年出版的第一版。本版本为技术修订版，包括与第一版相比的以下重大技术变更: -在第8条中，增加了应用于混响室的电场探头的用途和规格。 -在附件A中，关于在相对较低的工作频率（即。e.，接近给定腔室的最低可用频率），并概述了其对场不确定性估计的影响。 -在附录B中，当腔室表现出圆柱对称性时，场探头的对称位置是不允许的，因为这种放置可能会在不同位置产生场均匀性和腔室性能的错误指示。 -附录C现在包含了更多关于设定最大允许搅拌速度的定量指南，以保证腔室验证和测试的准静态操作条件。 -在附录D中，增加了EUT和设备在抗扰度试验中所占试验箱总容积不超过8%的要求。 -对附件E进行了扩展，进一步提供了用于估算辐射功率和场的EUT方向性值的指导。-在附件一中，增加了一些关于天线效率测量的说明。 -增加了新的附件K，涵盖混响室的测量不确定度。

IEC 61000-4-21:2011 considers tests of immunity and intentional or unintentional emissions for electric and/or electronic equipment and tests of screening effectiveness in reverberation chambers. It establishes the required test procedures for performing such tests. Only radiated phenomena are considered. The objective of IEC 61000-4-21:2011 is to establish a common reference for using reverberation chambers to evaluate the performance of electric and electronic equipment when subjected to radio-frequency electromagnetic fields and for determining the levels of radio-frequency radiation emitted from electric and electronic equipment. IEC 61000-4-21:2011 does not intend to specify the tests to be applied to a particular apparatus or system. Its main aim is to give a general basic reference to all concerned product committees of the IEC. The product committees should select emission limits and test methods in consultation with CISPR. The product committees remain responsible for the appropriate choice of the immunity tests and the immunity test limits to be applied to their equipment. Other methods, such as those covered in IEC 61000-4-3, CISPR 16-2-3 and CISPR 16-2-4 may be used. This second edition cancels and replaces the first edition published in 2003. This edition constitutes a technical revision and includes the following significant technical changes with respectto the first edition:
- In Clause 8, the use and specifications of E-field probes for application to reverberation chambers has been added.
- In Annex A, additional guidance and clarifications on the use of reverberation chambers at relatively low frequencies of operation (i.e., close to the lowest usable frequency of a given chamber) are given, and its implications on the estimation of field uncertainty are outlined.
- In Annex B, symmetric location of the field probes when the chamber exhibits cylindrical symmetry has been disallowed, as such placement could otherwise yield a false indication of field uniformity and chamber performance at different locations.
- Annex C now contains more quantitative guidance on the setting of the maximum permissible stirring speeds that warrant quasi-static conditions of operation for chamber validation and testing.
- In Annex D, a requirement for the EUT and equipment not to occupy more than 8 % of the total chamber volume in immunity testing has been added.
- Annex E has been extended with further guidance on the value of EUT directivity to be used in the estimation of radiated power and field.
- In Annex I, some clarifications on antenna efficiency measurements have been added.
- A new Annex K has been added that covers measurement uncertainty in reverberation chambers.