• Which Products are you interested in ?

    CST offers a wide range of EM simulation software to address design challenges across the electromagnetic spectrum, from static and low frequency to microwave and RF, for a range of applications, including EDA & electronics, EMC & EMI and charged particle dynamics.

  • Antenna Magus
  • IdEM
  • FEST3D
  • Optenni Lab
  • Looking for a Training, Workshop or eSeminar ?

    CST STUDIO SUITE® is being demonstrated at trade shows and workshops all over the world. Take a look at the list of conferences and exhibitions CST will be attending and get further information regarding CST workshops, eSeminars and training days.

  • TrainingsRegular training courses are held in CST's offices in Asia, Europe, and North America. Please check our trainings section for detail of trainings in all over the globe. Advance registration is normally required.

  • WorkshopsCST hosts workshops in multiple languages and in countries around the world. Workshops provide an opportunity to learn about specific applications and refresh your skills with experienced CST support staff. Make sure you visit our workshop section.

  • eSeminarsThroughout the year, CST simulation experts present eSeminars on the applications, features and usage of our software. You can also view past eSeminars by searching our archive and filtering for the markets or industries that interest you most.

  • Check our latest Events
  • Why create a MyCST Account ?

    A MyCST account may facilitate your access to many of the offerings on the CST website, for example the registration for eSeminars and the watching of eSeminars recordings, setting email preferences, and there is more functionality to come. It is required to participate in workshops and trainings.

  • Personal PreferencesAllows you to update your email preferences and areas of interest. It helps us to personalize your experience.

  • EventsSearch for events by location, industry and application. Once you are registered, you will be able to manage your registrations and check important details about your events. This section also provides you with a repository for Workshop & Training material.

  • LibraryYou can collect articles you find on the CST website to reference or read later by clicking on the “Add this article” button at the bottom of the article page.

  • Create Your Own Account
  • Need technical Support ?

    Customers can customize their accounts once they have completed the account creation process. This platform acts as vivid interface between CST and our customers.

    We therefore offer access to the latest Service Packs (including an automatic notification that a new Service Pack is available), a steadily growing database of Frequently Asked Questions (FAQs), Application Notes and Training Videos, as well as an individual FTP section for easy exchange of large files with our support team.

  • Do I need an Account?To access the Support Site a valid maintenance contract and a one-time registration is required.

    Please note that your Support login does not work for the MyCST account.

  • Get Support
  • How to request a Trial License ?

    Get your license in only three steps:

    1. Fill in the required fields in the contact form on the right and click "Send Us Your Request".

    2. Lean back and wait until one of our CST Experts contacts you.

    3. Enjoy a our trial license.

  • Student Edition

    Student Edition The CST STUDIO SUITE® Student Edition has been developed with the aim of introducing you to the world of electromagnetic simulation, making Maxwell’s equations easier to understand than ever. With this edition you have, bar some restrictions, access to our powerful visualization engine and some of the most advanced solvers of CST STUDIO SUITE.

    Student Edition

CST – Computer Simulation Technology

Horn Fed Gregorian Axisymmetrical Dual Reflector | Antenna Magus

Image of the Horn fed Gregorian Axisymmetrical dual reflector.

Dual-reflector antennas are based on principles that have been used in optical telescopes for centuries. The Gregorian telescope was the first dual lens optical telescope. It provided a revolutionary advantage, in that the observer could look through the telescope while standing behind the main reflector, without getting in the way of the light from the observed object (an effective way of reducing aperture blockage!).

The Gregorian dual-reflector antenna has a number of advantages when compared to the prime focus reflector. In cases where the housing for the feed electronics is electrically large, the feed can be positioned behind the primary reflector, reducing unwanted aperture blockage (provided, of course, that the sub reflector is smaller than the feed electronics). A second advantage is that for a given feed beamwidth the dual reflector configuration can reduce the antenna length and require shorter, less sturdy struts....

The Gregorian dual-reflector is a very popular antenna for very high gain applications. Similar to the Cassegrain reflector (already included in Antenna Magus), it transforms the low to medium gain radiation of the feed horn to a high-gain pencil beam.

Difference between the Gregorian and Cassegrain configurations.

The above image shows the difference between the Cassegrain and Gregorian configurations. The main difference is the position and shape of the sub-reflector. There are various factors (like main reflector size, feed angle, strut size, feed blockage etc.) that influence which one of these reflector configurations are preferable for a specific application.

The image below shows a comparison between three different reflector configurations, designed using Antenna Magus. Each of these are designed at 20 GHz for 40 dBi gain using a horn feed with a 10 dB beamwidth of 45 degrees.

Comparing length and width dimentions between the Cassegrain, Gregorian and prime-focus reflectors for a 40 dB gain design in Antenna Magus using a 45 degree 10 dB beamwidth horn feed in all three cases.

Note that the dual-reflector configurations both have much shorter physical lengths when compared to the single parabolic reflector. In the case shown, The Gregorian requires a primary reflector that is 11% wider than the Cassegrain to achieve the required gain. This is due to the aperture blockage.

The Gregorian reflector can be designed in Antenna Magus for gains from 30 to 50 dBi, and the positioning and dimensions of the feed horn are included. The radiation patterns shown below are for a Gregorian designed for an overall gain of 40 dBi, using a 10 dB feed beamwidth of 60 degrees.

Typical 3D radiation pattern at the center frequency.
Typical normalized radiation pattern at the center frequency.

Rate this Article

0 of 5 Stars
5 Stars
4 Stars
3 Stars
2 Stars
1 Stars
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.