Millimetre-wave amplifiers and oscillators have been developed and commercialized by CPI Canada for over five decades, utilizing Extended Interaction-type Klystron circuits. This type of circuit has proven to be an effective means of achieving high RF power with high electrical efficiency in a physically compact device. In this paper, an overview of recent advancements is provided, with a description of the applications driving these developments.

This paper presents test results on a new model of pulsed EIK amplifier operating at 263 GHz targeting applications in advanced weather radar, DNP enhancement of NMR systems and visual imaging for homeland security. This EIK delivered an output power greater than 70 watts, gain of over 30dB and a -3dB bandwidth greater than 1000 MHz.

Modern Dynamic Nuclear Polarization (DNP) experiments often utilize gyrotron sources for irradiation of electron spins at 140-593 GHz. The total cost of ownership, size, and complexity of gyrotrons, however, limits wider adoption. The introduction of lower-cost and more compact sources can have a significant impact on the DNP community. This contribution describes the development of a 263 GHz EIK, design of transmission line for optimal irradiation of the DNP NMR sample, and detailed performance characterization for DNP experiments.

An Extended Interaction Klystron (EIK) design has been developed to the support extreme signal stability requirements of space-borne interferometric applications. This is an unprecedented set of requirements for an EIK. In conjunction with the Canadian Space Agency (ASC/CSA)and Jet Propulsion Laboratory, Communications and Power Industries, Canada (CPI) advanced this development through testing of a heritage design EIK, testing a dedicated Demonstration Model EIK and an Engineering Model EIK. Each step of testing provided guidance in the development of the EIK Design, finally providing confidence in the EIK's ability to support the needs of the interferometric radar.

Rapid development of advanced millimeter wave radars affected all markets including space-borne Earth observation. Space missions require long-life, high power amplifiers in a compact package with high efficiency and reliability. The Extended Interaction Klystron technology has demonstrated its capability to meet or exceed all requirements for space-borne applications. This paper reviews EIK performance and the specifics of the development, qualification, fabrication and acceptance process. Brief description of current and future missions is presented.

Significant progress in modeling and manufacturing technologies open wide possibilities for performance improvements of millimeter-wave vacuum electron devices. However, many practical aspects should be considered to realize reliable long-life high-power sources. These are: thermal and RF stability, materials and assembly sensitivity to manufacturing, electrical stresses, cathode poisoning prevention, thermal beam effects, and many others. We address the full spectrum of design and manufacturing aspects while developing state-of-the-art extended interaction klystrons (EIKs). EIKs provide unprecedented RF performance and reliability in a compact user-friendly package. This paper discusses EIK design methodology and manufacturing concepts stating self-imposed restrictions and design modifications enhancing power capability, bandwidth, and extending operating frequencies into the terahertz region.

Pulsed and CW amplifiers and oscillators are being developed for applications requiring 1-20 W of power at frequencies up to 264 GHz. The design and test results will be presented for a 5W CW 187 GHz amplifier, a 5W CW 264 GHz oscillator, and a 20W pulsed 264 GHz amplifier. All three are compact (<; 8 kg) devices based upon Extended Interaction Klystron technology, and operate from commercially available power supplies.

We describe our progress on the development of extended interaction klystron amplifiers operating at 670 GHz, meeting demanding requirements for output power, gain, bandwidth, and efficiency.

The large-signal code TESLA (Telegraphist's Equations Solution for Linear-beam Amplifiers) was originally developed for the analysis and design of klystrons. It has now been applied to the simulations of an extended interaction klystron (EIK) for the first time. Results for the power transfer curve and bandwidth curves computed for a G-band EIK compare well to their measured values. TESLA obtains these results almost two orders of magnitude faster than a 3D particle-in-cell simulation code.

The development of new terahertz power amplifiers at 0.67, 0.85 and 1.03 THz presents significant challenges in both design and fabrication. This paper describes the design challenges and methodology, an outline design of the new device and an analysis of fabrication techniques considered.

The large-signal code TESLA (Telegraphist's Equations Solution for Linear beam Amplifiers) was originally developed for the analysis and design of klystrons. It has now been applied to the simulation of an extended interaction klystron (EIK) for the first time. Results for the power transfer curve and bandwidth curves computed for a G-band EIK compare well to their measured values. TESLA obtains these results almost on the two orders of magnitude faster than a 3D particle-in-cell simulation code.

This paper reviews the technology and demonstrated capability of millimeter wave Extended Interaction Klystrons for use in wide range of radar systems. It discusses design and manufacturing concepts stating selfimposed restrictions and design modifications to enhance RF performance, lifetime, reliability and extended operating frequency into the THz region. Presented data are supported using information provided by various academic and industrial customers.

EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is the 6th Earth Explorer Core Mission of the European Space Agency and a joint undertaking with the Japan Aerospace Exploration Agency (JAXA). It will study and analyze the interaction and impact of clouds and aerosols on the Earth's radiative budget. Along with other instruments, the satellite payload will include a 94 GHz Cloud Profiling Radar (CPR) with Doppler capability. This paper presents the development of a High Power Amplifier for the EarthCARE CPR and reviews HPA requirements, design and performance.

This paper reviews the technology and demonstrated capability of mmW and Sub-mmW Extended Interaction Klystrons at CPI Canada. It discusses design and manufacturing concepts stating self-imposed restrictions and design modifications enhancing power capability, bandwidth and extending operating frequency into the THz region.

This presentation describes the performance of a recently developed 218 GHz extended interaction klystron (EIK) amplifier producing 7W CW and weighing less than 4.3 kg.

The EIKs described have demonstrated capability to provide mmW power suitable for improved ESR and NMR systems. The performance of EIKs at 94 GHz and 220 GHz is reviewed and possibilities for future improvement in performance, including increasing frequency, will be discussed. Presented data are supported by information provided by various academic and industrial customers.

This paper presents on-orbit performance of the CloudSat extended interaction klystron (EIK) and reviews requirements, design and performance of EIK's for future space missions. The CloudSat mission provides cross-sectional view of clouds with information on their thickness, altitude, optical properties, water and ice content. It is concluded that following successful development and on-orbit operation of the CloudSat EIK, more flight models of W-band and Ka-band EIK's are currently under development.

This paper reviews the technology and demonstrated capability of mmW and Sub-mmW Extended Interaction Klystrons at CPI Canada. It discusses design and manufacturing concepts stating self-imposed restrictions and design modifications enhancing power capability, bandwidth and extending operating frequency into the THz region.

This paper reviews the demonstrated capability of mmW and Sub-mmW extended interaction klystrons at CPI Canada. It discusses design and manufacturing concepts including self-imposed restrictions followed by performance expectations into the THz region.