This software tool offers a 3D representation of the Smith chart.
This software tool offers a 3D representation of the Smith chart.
This software tool offers a 3D representation of the Smith chart.
This software tool offers a 3D representation of the Smith chart.
This software tool offers a 3D representation of the Smith chart.

The Smith Chart Enters a New Dimension

June 23, 2017
One team decided to transform the traditional Smith chart into a three-dimensional tool.

Download this article as a .PDF

The Smith chart, which is unquestionably one of the most important and fundamental aspects of microwave engineering, has a long history that spans more than 70 years. However, one team of engineers decided to take the classical Smith chart and put a much different spin on it. The result is a 3D Smith chart tool, which the team says is a new vision in microwave analysis and design (see figure).

The 3D Smith chart tool is an easy-to-install 3D representation of the classical Smith chart that is intended for high-frequency one- and two-port circuits. It works for all passive and active circuits—even when negative resistance is present. With this tool, users can observe impedance/admittance, as well as stability circles, group delay, quality factor, and unilateral power gain.

The 3D Smith chart differs from the traditional Smith chart in a number of ways. For example, as most already know, the center of the classical Smith chart denotes a perfect match. However, the 3D Smith chart shows a perfect match at the north pole.

In addition, RF/microwave engineers already know that negative resistance (|reflection coefficient| > 1) cannot be shown within the confines of the traditional Smith chart. However, negative resistance is indeed portrayed in the 3D Smith chart. Specifically, the south hemisphere represents negative resistance, with the south pole denoting an infinite reflection coefficient. The north hemisphere of the 3D Smith chart represents positive resistance. Furthermore, the inductive region is designated in the east, while the capacitive region is represented in the west.

Moreover, the program interface includes rendering options, which allow users to select the desired displays. These displays include constant normalized resistance (r), reactance (x), conductance (g), and susceptance (b) circles. Users can also modify colors, as well as the step between circles.

Analysis and Design

Users can take advantage of both analysis and design modes. With analysis mode, a touchstone file can be loaded to allow one to view a number of parameters on the 3D Smith chart. These parameters include impedance, stability circles, constant gain circles, group delay, quality factor, and unilateral power gain. The S-parameters can also be represented on a 2D Smith chart.

Design mode enables users to obtain normalized matching circuit solutions. One can simply enter the desired normalized impedance parameters and then choose a matching route. The corresponding resistance, inductance, and capacitance values, as well as transmission lines and stubs, can be directly computed.

Sponsored Recommendations

Frequency Modulation Fundamentals

March 14, 2024
The development of crystal-clear FM communications was an innovation of genius and toil. Utilized today in applications such as radar, seismology, telemetry and two-way radios...

44 GHz Programmable Signal Generator

March 14, 2024
The Mini-Circuits SSG-44G-RC is a 0.1 to 44 GHz signal source with an RF output range of -40 to +17 dBm with fine resolution. This model supports CW and pulsed (? 0.5 ?s) outputs...

Webinar: Introduction to OTA Measurement for mmWave and Sub-THz

Feb. 19, 2024
Join Jeanmarc Laurent, a leading expert from MilliBox, for an exclusive live webinar showcasing a complete Over-the-Air (OTA) testing system setup. In this immersive session, ...

Using a CMT VNA with Socket Server

Feb. 19, 2024
This application note describes use of a software application CMT Socket Server which is distributed and supported by Aphena Ltd. Please email [email protected] regarding purchase...