A quasi-monostatic reflective three-antenna method for antenna gain and scattering measurement

The three-antenna method is a well-known technique to measure the antenna gain without using a reference antenna. However, it operates in a transmission-type arrangement, a long return cable is then required. Several methods were developed to eliminate the return cable by using the radar cross section (RCS) measurement approach. We propose a quasi-monostatic arrangement that will greatly improve the measurement sensitivity. Three antennas are arranged as transmitting, receiving and reflecting antennas as shown, which is represented as a three-port network. By measuring the two-port scattering parameters at the reference planes of transmitting and receiving antennas while the reflecting antenna is terminated with three different terminators, the three-port scattering parameters can be calculated. One can then follow the three-antenna method to find the gain of each antenna. In addition, the structural scattering characteristics of each antenna can be solved.