Pyrotechnically operated S-band helical antenna is developed in which helix is deployed subsequent to antenna placement. Antenna is small, lightweight, and novel in that deployable helix is used in place of fixed dish or horn. It can be designed to cover L- and X-band frequencies

Cribb, H. E.

English

NASA Technical Reports Server

November 1970
	 Brief 70-10538 
NASA TECH BRIEF 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Lightweight S-Band Helix Antenna 
A pyrotechnically operated, S-band helical antenna 
has been developed in which the helix is deployed 
subsequent to antenna placement. The new antenna 
is small, lightweight, and is novel in that the deployable 
helix is used in place of a fixed dish or horn; an ad-
ditional advantage is that the antenna element can be 
shielded or protected when not being used. Applica-
tions include use on aircraft including helicopters, in 
mobile equipment, and in communications systems 
aboard satellites. This antenna should interest manu-
facturers of commercial communications equipment. 
One prototype developed for Sband frequency (see 
fig.) is an eight-turn helix designed to give 12 dh gain.
The antenna also can be designed to cover L- and X-
band frequencies, and in various configurations such 
as tn-helix and quad-helix. By increasing the numberof 
turns, more gain can be achieved. Other prototype 
models include one which incorporates a telescopic 
plunger, enabling the length of the antenna housing 
to be halved, and achieving a significant decrease in 
weight. 
In operation, a gas cartridge in the end of the 
antenna housing is activated bypassing current through 
a bridge wire igniting a powder charge. This releases 
gas pressure which forces the plunger to move forward 
in the antenna housing until the locking mechanism 
continued ocrka1) 
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passes through the back of the antenna housing. The 
locking spring arms extend and lock the plunger in 
place at a predetermined length. Attached to this 
plunger is a folded helix antenna; by choosing the 
proper length of the plunger, spacing can be obtained 
to ensure the desired beam width and antenna gain. 
To checkout the antenna, a restoring sleeve is at-
tached to the plunger. A suction cup is pressed over 
the antenna cover; the plunger must be pulled for-
ward slowly until the locking mechanism is activated. 
After checkout is complete, the plunger is pulled out 
approximately one-half inch; the storing sleeve is then 
pushed over the locking spring arms, making them fold 
into the plunger rod. The antenna is then pushed for-
ward until it is folded and reseated. 
This antenna can also be operated mechanically. The 
antenna housing has a slot running the length of the 
housing tube; the plunger face has a locking screw 
attached to it. To use the antenna in this configura-
tion, the locking screw must be pushed forward, lock-
ing it in place at the end of travel; this unfolds the 
helix to form an antenna with the proper spacing and 
length. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Kennedy Space Center 
Code AD-PAT 
Kennedy Space Center, Florida 32899 
Reference: B70-10538 
Patent status: 
No patent action is contemplated by NASA. 
Source: H.E. Cribb 
Kennedy Space Center 
(KSC- 10392)
. 
Li 
. 
Brief 70-10538
	 Category 02 
0


Lightweight S-band helix antenna

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