Design a DRO for airborne applications

The design, fabrication, and performance of a 1.325-GHz dielectric resonator oscillator (DRO) capable of operation in an aircraft vibration environment are described and illustrated. The DRO is housed in a 5 x 3-cm octagonal housing and employs an Si bipolar transistor as its active element, a varactor diode in the tuning loop to provide frequency control of + or - 2 percent or better, an open stub and capacitor connected to the emitter to provide the negative real impedance required at the collector, and a 1.3 x 3.0-cm electric resonator made from a ceramic of dielectric constant 88. The stability of the DRO output power (+10 dBm) against changes in temperature and against random noise vibration in all three axial directions is shown in graphs.