Identification and Suppression of Slot Modes in a Coaxial Magnetron

Abstract

This paper presents the details of identification and suppression technique of slot modes in X-band coaxial magnetron. Lower frequency slot mode is more susceptible to interfere with the desired mode of coaxial magnetron. An effective spurious mode suppression technique is proposed for such slot mode. A lossy dielectric ring is placed near the coupling slots inside anode shell. Analysis is carried out in eigenmode solver of CST. Quality factor of the unwanted slot mode is reduced by 98.56% by the proposed mode suppression technique while reducing quality factor of the desired mode by only 11%. Quality factor of the slot mode is obtained as 30 and for the desired mode as 10913 after the mode suppression. Mode suppressor also reduces the electric field strength of fringing field of the slot mode without affecting field strength of the desired mode.