Encapsulated RF inductor with an insulated coil has a high Q and remains stable for long periods of time at high temperatures. The coil is wound on a core and both are encapsulated in an epoxy resin. Two terminals are soldered to the coil

Wiler, E. M.

English

NASA Technical Reports Server

Ter ,inal 
May 1967	 .	 Brief 67-10106 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
RF Inductor Has High Q, Is Stable at Higher Temperatures 
Encapsulation 
(Powdered Iron in Epoxy Resin) 
(.011	 Core 
(Powdered Iron in Diallyl Phthalate) 
The problem: 
To design an encapsulated rf inductor that will have 
a relatively high Q and remain stable for long periods 
of time at temperatures up to more than 275° F. 
The solution: 
An inductor comprising an insulated coil wound on 
a core consisting of powdered iron in a binder of 
diallyl phthalate. The core and coil are encapsulated 
in an epoxy resin filled with powdered iron. Two 
terminals, projecting from the ends of the core, are 
soldered to the uninsulated ends of the coil. 
Inductors of this design have a Q ranging from 90 
to 100, which shows a negligible decrease after the 
inductors are heated at temperatures up to 275 0 F for 
2000 hours. These inductors should be useful for sev-
eral hundred hours at temperatures up to 5000F. 
Conventional inductors (of the same physical size) 
which typically employ a powdered iron core in a 
phenolic binder and an encapsulation consisting of an 
epoxy resin without a magnetic filler have a Q ranging 
from 55 to 65. The Q of these inductors may decrease 
by as much as 40 percent after the inductors are sub-
jected to 230° F for 2000 hours.
Notes: 
1. Although the Q of the improved inductor can be 
increased by increasing the proportion of powdered 
iron in the core, this proportion should not exceed 
87 percent by weight to keep the core from becom-
ing too brittle. 
2. Inquiries concerning this invention may be di-
rected to:
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B67-10106 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546.
Source: E. M. Wiler 
(JPL-l019) 
Category 01 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19670000106 2020-03-11T20:46:50+00:00Z


RF inductor has high Q, is stable at higher temperatures

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server