By Topic

A Design Method for Microstrip Directional Couplers Loaded With Shunt Inductors for Directivity Enhancement

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
$33 $13
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

2 Author(s)
Seungku Lee ; Department of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea ; Yongshik Lee

An accurate design method is proposed for directivity enhancement of microstrip directional couplers loaded with shunt inductors. The parasitic effects of junction discontinuities in various parts of such microstrip directional couplers have critical effects especially on the directivity, and therefore they must be taken into account. Without proper modeling of these parasitic effects, directivity enhancement becomes extremely difficult especially for weak coupling levels. The demonstrated method of analysis can be applied to obtain exact designs of all previous microstrip directional couplers that are loaded symmetrically with series and/or shunt reactance for directivity enhancement, regardless of the coupling levels. Based on the proposed method, a 20-dB microstrip directional coupler is designed at 2.4 GHz. A maximum directivity of 56 dB has been measured, which is an improvement of 48 dB over a conventional microstrip directional coupler. A 16.3% bandwidth at 2.4 GHz has been measured in which the directivity remains above 20 dB, while the maximum variation in the coupling level is 0.5 dB. This is the first work to demonstrate directivity of more than 50 dB for a 20-dB microstrip directional coupler.

Published in:

IEEE Transactions on Microwave Theory and Techniques  (Volume:58 ,  Issue: 4 )