It is possible to design and construct simple, efficient microwave antenna, either linearly or circularly polarized, which should be useful in phased arrays. Mounted on thin dielectric substrate, it extends slightly above ground plane. Space behind ground plane is required for feed line and mounting hardware

Howell, J. Q.

English

NASA Technical Reports Server

June 1973	 B73-10179 
NASA TECH BRIEF Langley Research Center
	
- & 
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 program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Microstrip Antennas 
It is now possible to design and construct a simple, 
efficient microwave antenna, either linearly or cir-
cularly polarized, which should be very useful in phased 
arrays. It is mounted on a thin dielectric substrate and 
extends only slightly above the ground plane. Space 
behind the ground plane is not required except for the 
feed line and mounting hardware. 
To build an antenna with the design center frequency 
very near the measured center frequency, it is necessary 
to first measure the antenna input impedance at the 
desired frequency and then design the matching network. 
The matching network determines the antenna band-
width and the actual resonant frequency (within a 
larger band, determined by the antenna size). 
To obtain a linearly polarized element, construct the 
antenna 
?j/2 
square at the end of a 50-ohm microstrip 
feed line (? d is the wavelength in the dielectric). Measure 
the impedance of the antenna in the frequency range 
of interest and design a matching network to transform 
the antenna impedance to 50 ohms. Reconstruct the 
antenna with the matching network on the same di-
electric substrate. It may be necessary to adjust the 
lengths of the transmission lines slightly to shift the 
center frequency to the desired point.
A circularly polarized wave will result if the antenna 
is made square and driven from two adjacent sides with 
signals 90 0
 out of phase. This may be done by in-
corporating a 900
 hybrid on the same dielectric sub-
strate as the antenna element and inserting the appro-
priate matching network between the antenna and the 
hybrid. 
It is also possible to build an antenna with two 
resonant frequencies by making it rectangular and 
driving it from adjacent sides. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Mail Stop 139A 
Hampton, Virginia 23665 
Reference: B73.10179 
Patent status: 
NASA has decided not to apply for a patent. 
Source: John Q. Howell
Langley Research Center
(LAR-1 1284) 
.
	
01 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000179 2020-03-17T07:10:26+00:00Z


Microstrip antennas

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server