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Microwave Filter | Thermalizer

Designed for mili-Kelvin and sub-mili-Kelvin experiments

Microwave filtering and thermalization of signal wires are two critical ingredients in setting up a sensitive low-temperature experiment. Our compact cryogenic microwave filter and thermalizer (MFT) unites efficient electron thermalization with ultra-strong microwave attenuation.

MFTs consist of a copper or other low-resistivity wire embedded in a highly conductive silver matrix. The silver matrix acts as a heat exchanger ensuring optimal thermalization.

The superior performance of single MFT filters was proven in an experiment that cooled a Coulomb blockade thermometer down to 7.5 mK with a dilution fridge temperature at 5 mK (ref: Scheller et al. APL 2014).

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Strong attenuation and thermalization
Low capacitance and low resistance

Strong attenuation of >100 dB above 130 MHz

~100 Ω & 2.5 nF @ 4K

or 

~25 mΩ & 2.5 nF @ 4K

Low capacitance for low noise

Low resistance for high current applications

> 1 TΩ resistance to ground

> 100 V maximum applied voltage

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Single MFT filters

SMA, MCX connectors or customized
Length 30 mm 
Diameter 6 mm

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Compact filter box

25 filters inside

Micro-D connectors

Non-magnetic copper box, gold-plated for best thermal contact

Easy to mount at 10 mK 

30 x 56 x 68 mm, 400 gr 

NEW: 2-pole RCRC stage option with 3dB cutoff down to kHz, integrated into the same compact box (see datasheet for full details)

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kHz cutoff with 2-pole RCRC stage

Integrated into the same compact MFT25 box

Standard cutoff options from 1 to 35 kHz 

Customized cutoff with application dependent R and C

See datasheet for full details

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Slim MFT package for small cryostat inserts

Each package includes 8 lines

Several packages can be stacked on top of each other

Up to 6 packages (48 lines) fit in a 50 mm insert

51 x 21 x 3.2 mm 
SIP-socket connectors for easy plugging/unplugging

Easy mounting on cold finger

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