Abstract: A microwave oscillator integrated in a waveguide includes a negative-resistance diode encapsulated in a capped micromodule, a capacitor fixed on the cap, a resonator fixed on the capacitor and a metallic strip fixed on the capacitor and on a grounding stud. The metallic strip constitutes a device for coupling the diode with the auxiliary load and with the resonator. Outside the resonance frequency of the resonator, no oscillation is possible since the diode is in that case loaded by a low resistance and is not capable of oscillating. The dielectric resonator is the only element which resonates, thus endowing the oscillator with high stability.