Convolution with Magnetostatic Waves in YIG Films

A recently reported theory is reviewed for the convolution of contra-propagating magnetostatic forward-volume waves (MSFVW) in an epitaxial yttrium iron garnet (YIG) film, which are in the form of continuous-wave signals or time-limited continuous-wave pulses. Initial experimental results on the convolution of contra-propagating MSFVW’s as well as of contra-propagating magnetostatic backward-volume waves (MSBVW) are reported. Computations of the MSFVW internal convolver hilinearity factor Fin, indicate an efficient convolution process over a wide bandwidth. The experimentally determined values of MSFVW Fint are in excellent agreement with theory. The present results will interest microwave system developers in electronic warfare and other areas, particularly if bandwidths of 1 GHz or larger can be realized in practice, even though magnetostatic-wave (MSW) delay lines, in comparison to SAW delay lines, are severely limited in terms of the maximum delay time that is realizable without excessive insertion loss, which is on the order of 0.5 CS. The reason for the interest in MSW convolvers (as, indeed, for the entire MSW technology) lies, of course, in the ability that is afforded for performing signal processing directly at microwave frequencies.