Good Performance of RT/duroid

5870 Microwave Laminate in a

Cryogenic Stripline Application at

NASA

RT/duroid

5870 laminate was evaluated as a stripline (triplate) transmission medium for use at cryogenic

temperatures by workers at NASA-Langley Research Center, Hampton Virginia. Microwave signals in the 8 to

40 GHz frequency range were to be transmitted into a 4°K cryostat for ampliﬁ cation by an ultra low noise

ampliﬁ er consisting of tantalum and lead elements deposited onto quartz substrate by electron beam plat-

ing.

Specimens of copper clad RT/duroid 5870 laminate 1 cm wide and 50 cm long were cycled repeatedly be-

tween 2.4°K and 290°K (17°C) by immersion in liquid helium. Adhesion of the copper foil remained sound.

The electrical length changed very little. The material became “somewhat brittle” at the low temperature, as

would be expected.

The insigniﬁ cant change in electrical length over the temperature range of concern indicates an interest-

ing balance of thermal behavior. The increase of dielectric constant due to increasing density with cooling is

offset by the decrease in length of the transmission line due to the linear thermal coefﬁ cient of expansion in

that direction. We have observed that PTFE composites of the RT/duroid 5870 type with low volume fraction

of highly oriented microﬁ ber reinforcement, show reduced ability of the oriented ﬁ ber to direct the volume

change toward the Z direction at low temperatures.

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The information in this data sheet is intended to assist you in designing with Rogers laminates. It is not intended to and does not

create any warranties express or implied, including any warranty of merchantability or ﬁ tness for a particular application. The

user should determine the suitability of Rogers laminates for each application.

These commodities, technology or software are exported from the United States in accordance with the Export Administration regula-

tions. Diversion contrary to U.S. law prohibited.

RT/duroid

and the Rogers' logo are trademarks of Rogers Corporation or one of its subsidiaries.

2015 Rogers Corporation, Printed in U.S.A.

Revised 1154 051415 Publication #92-281

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