RF Generation Using a Compact Gyromagnetic NLTL with Permanent Magnets

Abstract

Gyromagnetic nonlinear transmission lines (NLTLGs) consist of a ferrite-loaded coaxial line [1] to generate RF mainly in the L band (1-2 GHz). The growing interest in these devices is due to their capability of operating without the use of auxiliary systems required by conventional vacuum-based tubes employed in high power microwave (HPM) sources for mobile defense platforms and their good frequency tunability. Another promising area for NLTLG applications in space lies in synthetic aperture radars (SARs) for remote sensing since they work in the pulsed mode. However, the loaded ferrite line requires an external magnetic field for biasing. On the other hand, space applications need to replace the line solenoid and its feeding DC source for the compactness and weight reduction of the system. Therefore, the solution is substituting the magnetic bias with lighter and smaller permanent magnets [2] . In short, the paper's goal is to present the experimental results obtained using a compact 60-cm NLTLG built in our lab with NiZn ferrites and a structure of neodymium magnet rings. In the experiment, a 6-12 kV Gaussian input pulse generator from FID Technology with 12ns of pulse duration fed the line, and the results showed that RF generation produced was around 2 GHz.