Measurement of Electromagnetic Feedthrough in Spin Wave Based Microwave Multiport Devices

Multiport radio-frequency (RF) input devices are designed to handle multiple signals simultaneously. These devices typically consist of multiple input ports that can receive different RF signals and combine them into a single output or distribute them to multiple outputs. For example, in wave computing, majority gates use an odd number of inputs and one output. This paper investigates the electromagnetic feedthrough of a 3-input/1-output majority gate layout based on spin waves (SWMGs) and U-shaped microwave spin-wave transducers. The paper addresses the challenges of electromagnetic feedthrough by exploring shielding techniques to understand and improve the performance of the SWMG. As a tradeoff in complexity and performance, the unshielded layout is optimized and fabricated on a 500 nm Yttrium Iron Garnet (YIG) film. Measurements of scattering (S-) parameters demonstrate spin wave propagation at 8 GHz for a 200 mT magnetic bias field, with reduced electromagnetic coupling. Furthermore, the study includes an analysis of the effective permittivity and loss tangent of Gadolinium Gallium Garnet (GGG) substrate, critical for accurate electromagnetic modeling of the device.