CST – Computer Simulation Technology

Self-complimentary 4-arm Archimedes Spiral Antenna

Image of the Self-complimentary 4-arm Archimedes spiral antenna Image of the Self-complimentary 4-arm Archimedes spiral antenna

At first glance, the 4-arm spiral is only a 2-arm self complimentary with 4 arms - but if you look closely it is a lot more than that. The addition of 2 extra arms improves the axial ratio, but it also introduces some extra capabilities. The 4-arm spiral can operate very much like the 2-arm spiral (often referred to as sum mode, or mode 1 operation), but a difference mode (mode-2) is also possible.

By using the correct feed network and signal processing, each arm of the 4-arm spiral can be fed 90 degrees out of phase, allowing mode-1 operation which produces a radiation pattern with a maximum in boresight. When feeding each arm 180 degrees out of phase mode-2 operation produces a boresight null. The 3D radiation patterns produced by these two operating modes as shown in the image below....

Typical mode-1 and mode-2 RHC gain patterns across the operation band Typical mode-1 and mode-2 RHC gain patterns across the operation band

A beam forming network is often used to combine these two modes of operation vectorially, to form Σ + Δ, Σ - Δ, Σ + jΔ, Σ - jΔ corresponding to four squinted beams. This method is popular in tracking radar applications where the antenna can be steered in the right direction when the target is moving away from the center null into one of the 4 quadrants.

Rate this Article

0 of 5 Stars
5 Stars
0%
4 Stars
0%
3 Stars
0%
2 Stars
0%
1 Stars
0%
contact support

Your session has expired. Redirecting you to the login page...

We use cookie to operate this website, improve its usability, personalize your experience, and track visits. By continuing to use this site, you are consenting to use of cookies. You have the possibility to manage the parameters and choose whether to accept certain cookies while on the site. For more information, please read our updated privacy policy


Cookie Management

When you browse our website, cookies are enabled by default and data may be read or stored locally on your device. You can set your preferences below:


Functional cookies

These cookies enable additional functionality like saving preferences, allowing social interactions and analyzing usage for site optimization.


Advertising cookies

These cookies enable us and third parties to serve ads that are relevant to your interests.