ently, the free space mismatch and power correction coefficient for the reference antenna can be calculated by the following equations: (12.14) (12.15) C 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology The reference transfer function Gref represents the average net power transmis- sion in the chamber (i.e., corrected for mismatch on both transmit and receive antenna), as well as radiation efficiency of the reference antenna. Calculate the reference transfer function by the following equation: (12.16) where Nref is the radiation efficiency of the reference antenna, and N, n, Rfix and Rref are as defined before. Note that Gref can be conveniently used to determine the quality factor or, equivalently, the average mode bandwidth of the cavity, as shown in Equation (12.5). The application of the calibration on measurement data is shown next for each specific measurement case. 12.3.1 Measurement of Antenna Efficiency Radiation efficiency is an important parameter for all different types of antennas. For electrically small antennas used in various multipath scattering environments, it is, in fact, the dominating factor for the antenna performance. Classically, radia- tion efficiency is defined as the radiated power from an antenna structure divided by the power delivered to the antenna [19] (i.e., a measure of the loss in the antenna structure itself). In this text, the term total radiation efficiency is used to describe the efficiency of an antenna including its mismatch loss. Total radiation efficiency is thus defined as the radiated power from an antenna structure divided by the total available power at the antenna port. A basic property of the reverberation chamber is that the average received power of an antenna, taken over a complete stirrer sequence, is proportional to the total radiation efficiency of the antenna. Radiation efficiency can therefore be measured by a relative measurement, where the average received power for the test antenna is compared to the averag