Extension of the Kennaugh Null Theory

摘要

In radar polarimetry, Kennaugh first introduced the concept of the characteristic polarization states. Later, Huynen re-developed Kennaugh's work, and introduced his famous "polarization fork" concept illustrating that the characteristic polarization states in the copolarized channel form fork on the Poincare sphere. In a co-polarized or cross-polarized channel, the polarization states of the transmitting and receiving antennas are the same or orthogonal, and the corresponding target nulls (i.e., the CO-POL Nulls and X-POL Nulls) have been studied in detail, notably by Boerner and his collaborators. However, no systematic studies have been carried out to solve the problem of the corresponding target nulls if the polarization states of the transmitting and receiving antennas are independent. We know nothing except that there exist infinite pairs of transmitting and receiving polarization states such that the received power equals zero. Therefore, it is necessary to systematically study the target null problem for the case that the polarization states of the transmitting and receiving antennas are independent.