Modeling and design of millimeter wave gyroklystrons

A series of high power, high efficiency K-a-band and W-band gyroklystron ex periments has been conducted recently at the Naval Research Laboratory (NRL ). Stagger tuning of the cavities for bandwidth enhancement is commonly use d in the conventional multicavity klystrons. The desired stagger tuning is usually achieved via mechanical tuning of the individual cavities. However, in the millimeter wave regime, particularly, in the case of the high avera ge power operation, it is desirable to be able to achieve the required stag ger tuning by design. The NRL gyroklystron experiments explored the tradeof fs between power, bandwidth, efficiency, and gain to study the effects of l arge stagger tuning in millimeter wave without resorting to mechanical tuni ng of the cavities. Both, K-a-band and W-band, experiments demonstrated a r ecord power-bandwidth product. The success of the experiments was due in la rge part to a battery of improved large-signal, stability, and cold test co des employed in the modeling and design stage. Theoretical models that prov ide the basis for these design simulation tools and the design methodology will be presented. (C) 1999 American Institute of Physics. [S1070-664X(99)9 2905-1].