Contents I. Introduction
The high frequency capabilities of complementary metal-oxide-semiconductor (CMOS) technology and availability of 7 GHz of unlicensed spectrum around 60-GHz have made highly integrated radio circuits available at mm-wave frequencies, which reduce the cost and power consumption of mm-wave radios. The ability to test and characterize mm-wave antennas operating in the V-band is essential for the successful design. However, in the V-band, the high cost of radio frequency electronic equipment and absorbing materials makes this task very challenging. An alternative method for antenna gain measurements is to use two identical test antennas placed face-to-face and separated by a distance equal to far-field separation of reference planes. In this set one antenna functions as a transmit antenna, the other as a receive antenna and the antenna gain is estimated from the transmission measurements [1].
