By Topic

Coupled transmission lines as symmetrical directional couplers

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $31
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

1 Author(s)

If two similar unbalanced transmission lines are coupled together by sharing a common outer conductor for part of their length, so as to form a 3-conductor line, they constitute a symmetrical directional coupler. The output ratio of this varies sinusoidally with frequency, being greatest for lengths equal to an odd number of quarter-wavelengths; the characteristic impedance is independent of frequency, being determined by the cross-section of the 3-conductor line. Two forms of the directional coupler are described. One of these, intended for laboratory power measurement at frequencies up to 1 000Mc/s, consists of two parallel strips enclosed in a square-section outer conductor. The other, a very simple device for monitoring transmitter power, consists of two lead-covered coaxial cables grafted together. Among possible uses suggested are all-pass filters and applications to aerial systems consisting of two parts fed in phase quadrature.

Published in:

Proceedings of the IEE - Part B: Radio and Electronic Engineering  (Volume:102 ,  Issue: 3 )