Phase Locked Magnetrons

A research effort is described that will develop high fidelity design tools and, in Phase II, the implementation of a reliable phase-locked magnetron pair based on the California Tube Laboratory (CTL) CWM-75/100L magnetron. Two approaches to phase locking will be examined and modeled in this Phase I effort; i) phase locking via an anode-side cavity field probe, and ii) phase locking via a grid-cathode design. The two approaches examined in this work will be compared relative to i) the reliability of phase locking, ii) the interval to lock, and iii) the ultimate output power produced by the tube. The design tools are expected to be built on two Electro-Magnetic (EM) modeling tools; a Maxwell solver for impedance and coupling analysis (CST), and a particle-in-cell solver to demonstrate phase locking (ICEPIC). The Phase I products will be the engineering modeling tools as well as the mechanical specifications for an augmented CWM-75/100L using the superior phase locking approach. BENEFIT: This research effort is anticipated to provide the following benefits: 1. A conclusive high-fidelity model of the required modifications to a commercial L-band magnetron that will yield positive phase locking control in a master-slave mode. This is an essential development if the phase-locked magnetron transmitter is to mature to the reliability level required for military applications. 2. A phase locking design solution that does not depend on fine-tuned feedback in the output and combining manifold and waveguides of a multi-magnetron transmitter. Removing this requirement eases design constraints on the transmitter and allows fully matched systems to be built, increasing power output to the antenna and target. 3. With the ability to firmly control the phase of an individual magnetron, pairs of magnetrons can also be run asynchronously, creating the beat effect, or hearing effect that might prove useful in Active Denial (AD) applications, also demonstrable in Phase II. 4. In Phase II, a proof of concept demonstration that will enable utilization of phase locking in high reliability military applications. There are a number of military applications, mostly in the area of counter-electronics that would be enabled by a robust solution, fundamentally derived from high fidelity modeling, to the phase locking of magnetrons. At the current state of understanding of these systems the applications are still at the laboratory stage of development. Some laboratory systems are known to the authors to represent the best current solution to the most urgent current military counter-electronics and counter-IED technical challenges. All advances to the state of the art in reliability and design certainty of these systems present a commercial opportunity for the development of defensive military tools. Additionally there are commercial opportunities for very high power sources in the area of long range radar and space object tracking.