018/100 Short-circuited Transmission Line

100 ADS Design Examples Based on the Textbook: RF and Microwave Circuit Design
November 2019
Michael Benker

Example 2.11-2A: Calculate the input impedance of a short-circuited microstrip transmission line for a given electrical length of the line.

This circuit was built with a quarter-wave microstrip synthesized for 10 GHz with given substrate (conductivity of gold) using the LineCalc tool.


The following results conclude that a short-circuited quarter-wave transmission line has high impedance, similar to an open circuit. A short circuited transmission line that is not a quarter-wave transmission line will not have high impedance as demonstrated by frequencies far outside of the range of optimization (10 GHz). This phenomena is is consistent with electromagnetic theory on transmission lines.


Theoretical relationship between transmission line length (short-circuited) and it’s imaginary impedance component:



1 thought on “018/100 Short-circuited Transmission Line

  1. Pingback: 019/100 Open-Circuit Transmission Line | RF/Photonics Lab

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s