Analysis of injection-locked antenna array

An analysis of dipole antenna array with each element loaded with an active device (i.e., two-terminal oscillator) is presented. The analysis is equivalent to solving a multiport network circuit with each port shunted with a two-terminal oscillator and an equivalent exciting source. A characteristic equation with the order of 2N is derived to describe the stability condition of an N-element injection-locked active antenna array. The Routh-Hurwitz stability criterion is then applied to remove the unstable solutions. Numerical results show that the array performance such as the frequency locking range, by taking into the array mutual coupling effect, is quite different from that of an isolated antenna element.