Richard Dobbs

Vacuum Electronic High Power Terahertz Sources

Recent research and development has been incredibly successful at advancing the capabilities for vacuum electronic device (VED) sources of powerful terahertz (THz) and near-THz coherent radiation, both CW or average and pulsed. Currently, the VED source portfolio covers over 12 orders of magnitude in power (mW-to-GW) and two orders of magnitude in frequency (from <; 0.1 to >; 10 THz). Further advances are still possible and anticipated. They will be enabled by improved understanding of fundamental beam-wave interactions, electromagnetic mode competition and mode control, along with research and development of new materials, fabrication methods, cathodes, electron beam alignment and focusing, magnet technologies, THz metrology and advanced, broadband output radiation coupling techniques.

Practical Aspects of EIK Technology

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.

A compact, high power, sub-millimeter-wave Extended Interaction Klystron

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.

9.2: Fabrication techniques for a THz EIK

To produce an EIK working at THz frequencies, departure from traditional fabrication techniques is required. This paper describes the investigation and results of various fabrication techniques and their suitability for application in a VED.

Advantages of the Extended Interaction klystron Technology at Millimeter and Sub-Millimeter Frequencies

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.

15.4: Design of terahertz Extended Interaction Klystrons

The development of terahertz power amplifiers presents significant new challenges as it brings into focus design, fabrication, and measurement issues that are not important factors at lower frequencies. In this paper, we describe our design approach to meet these challenges with particular emphasis on a 0.67 THz Extended-Interaction Klystron (EIK). This device is being designed to generate a peak power of ∼0.5W with gain of ∼23 dB over an instantaneous bandwidth of 15 GHz. The circuit will be driven by a 100 mA, 25kV electron beam confined in a 0.005″diameter beam tunnel with ∼1 Tesla magnetic field. This choice of beam size ensures that the same electron gun can be employed for all program development phases culminating in a 1.03 THz amplifier. A highly efficient depressed collector has also been designed to meet the efficiency requirement.

Extended Interaction Klystrons for terahertz power amplifiers

Extended Interaction Klystrons have been demonstrated at frequencies up to 218 GHz CW and 229 GHz pulsed. Modern design, fabrication, and measurement technologies show promise of extending their operation into the THz regime. This paper describes the challenges and some novel approaches to the development of EIKs operating terahertz frequencies, while simultaneously meeting demanding requirements for output power, gain, bandwidth, and efficiency.

Design and fabrication of terahertz Extended Interaction Klystrons

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.

12.3: Extended Interaction Klystrons for terahertz power amplifiers

Extended Interaction Klystrons have been demonstrated at frequencies up to 218 GHz CW and 229 GHz pulsed. Modern design, fabrication, and measurement technologies show promise of extending their operation into the THz regime. This paper describes the challenges and some novel approaches to the development of EIKs operating at 670, 850 and 1030 GHz, while simultaneously meeting demanding requirements for output power, gain, bandwidth, and efficiency.

Rugged and Efficient Ka-Band Extended Interaction Klystrons for Satellite Communication Systems

In this paper, CPI Canada enhancement of the capabilities of the Ka-band extended interaction klystrons (EIK) for the Satcom Communication Uplink community is discussed.