Design Considerations of an Active Integrated Antenna with Negative Resistance Transistor Oscillator

The design of an active integrated antenna with negative resistance transistor oscillator has been described. Simple but reasonably accurate analysis of oscillation start-up and steady state operating frequency prediction is presented. The active antenna prototype was manufactured and its operating frequency, EIRP and radiation patterns were measured. Two of these antennas were integrated in active arrays coupled in E- and H-planes. The inter-element distance in the arrays was optimized to obtain in-phase operation and mutual injection locking. Very good power combining efficiency was measured and beam scanning capabilities were demonstrated for both arrays.