A Microwave Signal Correlator using Parametric Pumping of Spin Waves

This work demonstrates parametric interactions of spin waves to implement a device capable of correlating microwave signals encoded with 16-bit codes. Signal processing correlators are devices that compare two signals, such as a reference code and a received code, where the output indicates the similarity between the signals. Correlators are used in communication systems such as wireless mobile networks, wireless local area networks, and the global positioning system in order to increase signal-to-noise ratio and in some cases to selectively communicate with individual devices. Modern correlators are implemented using digital components, which requires complex circuitry. Other state-of-the-art analog correlators exist, but these correlators have the limitation of not being reprogammable. This work implements a novel analog correlator using a microwave magnetic field to parametrically pump spin waves in a yttrium iron garnet thin film. The correlator operates! at microwave frequencies, has a simple topology, and offers code reprogrammabilty. The performance of the correlator was verified by computing the cross-correlation of 16-bit orthogonal Walsh-Hadamard codes. The processing gain achieved by the correlator in this work was 10.57 dB for 16-bit codes, which is 71.3\% of the theoretical maximum.

Major Advisor: Pallavi Dhagat
Committee: Albrecht Jander
Committee: Huaping Liu
GCR: Ethan Minot