Repetitive sub-gigawatt rf source based on gyromagnetic nonlinear transmission line

Abstract

We demonstrate a high power repetitive rf source using gyromagnetic nonlinear transmission line to produce rf oscillations. Saturated NiZn ferrites act as active nonlinear medium first sharpening the pumping high voltage nanosecond pulse and then radiating at central frequency of about 1 GHz: shock rise time excites gyromagnetic precession in ferrites forming damping rf oscillations. The optimal length of nonlinear transmission line was found to be of about 1 m. SINUS-200 high voltage driver with Tesla transformer incorporated into pulse forming line has been designed and fabricated to produce bursts of 1000 pulses with 200 Hz repetition rate. A band-pass filter and mode-converter have been designed to extract rf pulse from low-frequency component and to form TE(11) mode of circular waveguide with linear polarization. A wide-band horn antenna has been fabricated to form Gaussian distribution of radiation pattern. The peak value of electric field strength of a radiated pulse at the distance of 3.5 m away from antenna is measured to be 160 kV/m. The corresponding rf peak power of 260 MW was achieved.

Simulation Studies of Distributed Nonlinear Gyromagnetic Lines Based on <italic>LC</italic> Lumped Model

“…Simulations were also performed using a different SPICE model for the line nonlinearity given by an exponential function according to (5). The simulation runs were fulfilled for a ferrite NLTL based on an improved Pouladian-Kari et al's [14] model described with two different kinds of axial magnetic bias, constant and linearly graded.…”

Bias-field controlled phasing and power combination of gyromagnetic nonlinear transmission lines

“…An example of this effect is the large diameter system demonstrated by Romanchenko that generates several hundred MW at a frequency 1.2 GHz. 5 Therefore, in order to reach higher power a) david.reale@ttu.edu levels at frequencies compatible with smaller diameter lines (∼8-10 mm), the outputs of multiple NLTLs are combined. Power combination can be achieved via free space, i.e., an array of radiating elements, or in a guided structure.…”

Wideband RF Radiation from a Nonlinear Transmission Line with a Pre-magnetized Ferromagnetic Core

“…[4,5]. In some of these the output signal from a coaxial NLTL was fed to a circular waveguide through a TEM-to-TE 11 mode converter and further on to a conical horn antenna.…”

“…Despite the impressive history of NLTL studies [1][2][3][4][5][6][7], experiments on extracting and radiating the intense RF signals have been detailed in just a few papers, e.g. [4,5].…”