Dispersion Engineered Frequency Tunable Delay Platform based on Magnetostatic Surface Waves

TL;DR

This paper introduces a reconfigurable microwave delay platform using magnetostatic surface waves in microfabricated YIG waveguides, achieving wideband tunability, low loss, and high Q-factors for advanced RF signal processing.

Contribution

It demonstrates a novel, microfabricated YIG-based microwave delay platform with continuous frequency tuning and superior performance over existing acoustic delay lines.

Findings

Tunable from 6 to 19.6 GHz with delays up to 42.8 ns

Achieves low insertion loss of 2.5 to 10.1 dB

Exceeds state-of-the-art fixed acoustic delay lines in Q-factor

Abstract

Reconfigurable radio-frequency front ends in modern radar and wireless systems require delay elements that simultaneously offer low-loss, low noise, compact form factor, and wideband frequency agility. However, electromagnetic, acoustic, photonic, and active-circuit delay technologies each fail to deliver this combination. Here we report a microwave delay platform based on magnetostatic surface waves (MSSWs) in microfabricated 18 $\mu$m yttrium iron garnet (YIG) waveguides, in which co-engineering the spin wave dispersion with the radiation impedance of meander-line transducers grants pitch-controlled access to distinct dispersive or near-constant group-delay regimes. Tuned continuously from 6 to 19.6 GHz under magnetic bias, the delay lines deliver group delays of 3.3 to 42.8 ns at insertion losses of 2.5 to 10.1 dB and nonreciprocal isolation of 24 to 39 dB, all measured directly into 50 $\Omega$ without external impedance matching. Length-resolved characterization yields unit-time propagation losses of 56 to 109 dB/$\mu$s and propagation Q-factors that rise monotonically from 3002 to 4893 across the operating range, exceeding state-of-the-art fixed frequency acoustic delay lines at every benchmarked frequency. These results establish microfabricated YIG as a versatile, low-loss microwave platform for next-generation reconfigurable RF signal processing.