Two-dimensional Unilaterally Coupled Active Antenna Arrays with Wide Angle Beam Scanning Capability

A unilateral coupling scheme for twodimensional active antenna arrays was developed. Each oscillator is coupled to one of its neighbor oscillators unilaterally in a comb-like arrangement. The phase shifts along both axes of the array can be controlled by adjusting the frequency of only the back oscillators. Two paths, which are different in length and each contains an amplifier, were employed for unilateral coupling. Turning on the desired one out of two amplifiers, one can change the range in which the phase shift can be varied. In a 2×2 experimental oscillator array, the main beam could be scanned 40° in H-plane and 25° in E-plane totally.