A bi-directional active lens antenna array

We present a passive and an active 2D lens antenna array fed from the focal point in the near field, eliminating the corporate feed structure at the plane of the array. The active circuits in each element of the active array perform transmit and receive functions. In transmission, a source illuminates the array from the focal point, and in reception the signal is received at the same focal point. Used as a front end in a communication system, the array can reduce the effects of multipath fading. A lens array can also add angular diversity to a receiver, by placing several receivers along the focal surface. In transmission, the array offers increased ERP. Because the noise in each element is uncorrelated and the power is combined in free-space, the array offers increased dynamic range in reception. We present l0-element passive and active lens amplifier arrays designed for X-band and operating in both transmitting and receiving modes.