Permanent magnet focused, multi-stage depressed collector klystron amplifiers for satellite communications

A new line of high-efficiency multi-stage depressed collector (MSDC) klystron amplifiers has been developed by Communications and Power Industries Microwave Power Products (CPI/MPP) for use in satellite communications and scientific applications market. These klystrons are air-cooled with permanent magnet focusing. The first products are designed to service the satellite uplink and terrestrial repeater markets. MSDC technology for these applications can reduce power consumption by as much as 60%. A general discussion about the benefits of MSDC technology for these applications, as well as two examples of their use, are presented. CPI/MPP has developed the VKU-8891M series klystrons which provide 2.4 kW CW tunable in the frequency range from 17.3 to 18.4 GHz with instantaneous bandwidths up to 85 MHz. The klystron is designed with a 4-stage MSDC which has increased the saturated efficiency of the device from 24% to 40% A detailed discussion of the design, as well as a comparison between simulation and experiment, is presented. CPI/MPP is also developing the VKS-7964M klystron in the frequency range from 2.1 to 2.4 GHz, with instantaneous bandwidths up to 8 MHz. This klystron has a 4-stage MSDC. The simulated efficiency of this klystron approaches 60%. We predict the measured efficiency. A detailed discussion of the design, as well as a comparison between simulation and experiment, is presented.