Multilayer Cryogenic Powder Filters with Low Parasitic Capacitance

TL;DR

This paper introduces a multilayer cryogenic powder filter that achieves high GHz RF attenuation while significantly reducing parasitic capacitance, improving measurement fidelity in sensitive cryogenic experiments.

Contribution

The authors develop a novel multilayer filter design that combines high RF attenuation with minimized parasitic capacitance, enhancing cryogenic measurement setups.

Findings

Achieves high GHz RF attenuation with multilayer design

Reduces parasitic capacitance compared to conventional filters

Suppresses RF-induced sample heating effectively

Abstract

We report the development of a cryogenic powder filter that simultaneously offers high attenuation of radio-frequency (RF) signals in the gigahertz (GHz) range and minimized parasitic capacitance to ground. Conventional powder filters, which consist of a signal line passing through a metal powder-filled housing, attenuate high-frequency signals via the skin effect. However, these designs often suffer from significant parasitic capacitance between the signal line and the grounded chassis, which can compromise the performance of sensitive measurement setups by limiting their frequency bandwidth. In this work, we demonstrate that a multilayer powder filter design effectively achieves both high RF attenuation and reduced parasitic capacitance. This solution suppresses sample heating due to the unintentional intrusion of RF signals through the wiring, without degrading the performance of the measurement setup.