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

The design of an active integrated antenna with negative resistancetransistor oscillator has been described. Simple but reasonablyaccurate analysis of oscillation start-up and steady state operatingfrequency prediction is presented. The active antenna prototype wasmanufactured and its operating frequency, EIRP and radiation patternswere measured. Two of these antennas were integrated in active arrayscoupled in E- and H-planes. The inter-element distance in the arrayswas optimized to obtain in-phase operation and mutual injectionlocking. Very good power combining efficiency was measured and beamscanning capabilities were demonstrated for both arrays.