An edge-coupled magnetostatic bandpass filter
Connor Devitt, Renyuan Wang, Sudhanshu Tiwari, Sunil A. Bhave
Abstract
The further development of 5G and 6G communication systems introduced new frequency allocations beyond 6 GHz, necessitating the development of compact bandpass filters that can operate over wide gigahertz frequency ranges. Herein, we report on the design, fabrication, and characterization of an edge-coupled magnetostatic forward volume wave bandpass filter (MSFVW). Using micromachining techniques, we fabricate both 2-pole and 4-pole filters from a yttrium iron garnet (YIG) film grown on a gadolinium gallium garnet (GGG) substrate with inductive transducers. By adjusting an out-of-plane magnetic field, we demonstrate linear center frequency tuning for a 4th-order filter from 4.5 GHz to 10.1 GHz while retaining a fractional bandwidth of 0.3%, an insertion loss of 6.94 dB, and a − 35 dB rejection level. We characterize the filter nonlinearity in the passband and stopband with IIP3 measurements of − 4.85 dBm and 25.84 dBm, respectively. In this work, we demonstrate a compact octave tunable narrowband channel-select filter with a significant degree of design flexibility and performance comparable to the state-of-the-art. Since the development of mobile networks over 30 years ago, the amount of data, and therefore the required bandwidth for mobile networks has grown substantially. Future expansion relies on the GHz frequency range, this requires filters able to operate at GHz frequencies and fit into devices. Here Devitt et al demonstrate a magnetostatic bandpass filter, tunable over a wide range, from 4.5 GHz to 10.1 GHz.