• 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

MIMO Systems Simulations for Automotive Environment

Multiple Input Multiple Output (MIMO) systems have garnered a lot of attention recently in antenna system research, and they are often used to improve the quality of service and efficiency of wireless communications. The automotive environment is an especially challenging problem for antenna systems, since the large metal chassis of cars can have a very negative impact on their performance. Modern automobiles also must accommodate an ever increasing number of wireless services, that all require cabling inside the car from the antenna to the transceiver. As the number grows, it is increasingly hard to accommodate them all due to the limited space for antennas and cabling. MIMO systems could thus provide a much needed improvement in these situations. The research presented here is based on the Master of Science thesis by Arttu Rasku from Tampere University of Technology, Finland (http://www.tut.fi). The research work was done in Elektrobit, Finland (http://www.elektrobit.fi)....

Figure 1: Advanced car model for CST MWS simulations

CST MICROWAVE STUDIO® (CST MWS) is ideal for automotive simulations for a number of reasons: the geometries can be easily imported and modified using the powerful interface; the robust and accurate PERFECT BOUNDARY APPROXIMATION® (PBA) allows efficient meshing, thus reducing the computational requirements; and the memory usage of the transient solver grows linearly as a function of mesh cells allowing very large scale simulations, and also allowing the simulation of broadband AM/FM, GSM and GPS antennas. In this study, special emphasis was on the placement of the antennas on the car body. The parametric modeling and the parameter sweep features of CST MWS allows easy automatization of the antenna placement, thus reducing the time spent on setting up the simulations.

Figure 2: Basic car model for CST MWS simulations

In the study, two car models were used for simulations: A dummy model, i.e. the so-called basic car model (BCM), and an advanced car model (ACM) based on third generation (E34) BMW 5 series 4-door sedan from the early 1990’s. The BCM model was also used for radiation pattern measurements that were done at VTT Technical Research Center of Finland facilities in Espoo, Finland. For the antennas two types of monopole antennas – cylindrical and flat bar – with center frequency of 700 MHz were used in the simulation, but only the flat bar model was used in the measurements. Due to the limited time and resources, only two-antenna arrays were used for the final measurements.

Figure 3: Flat bar and cylindrical monopole antenna prototypes

The final antenna placements used in the measurements are shown in the Figure. 4. Two types of linear arrays were used, transverse and longitudinal. In the first case, the distance of both antennas from the roof rear edge varied between 60 mm and 770, and the spacing between antennas varies between 0.5 and 1.25λ. These configurations are shown as black boxes. In the latter configuration, shown as green boxes, both antennas were placed on the center line, and the spacing between them was varied as shown in the picture.

Figure 4: Placement of the antenna elements on the roof of the BCM car model. The black boxes mark the transverse array antenna location, and the green ones the longitudinal array element locations

As can be seen from the Figures 6 and 7, the differences in the simulation results between the two car models BCM and ACM are very small. As can be expected, the ACM model results have more ripples, whereas the BCM model results are quite smooth. The direction of the peaks and nulls agree well, as do the general gain levels. Figure 6 shows a comparison of the simulation results for various distance of the transverse antenna array with 0.5λ element spacing. As can be seen, the variation between the results is very small, thus the effect of the distance from the roof edge is not very large. For the array closest to the roof edge the results show some more ripple, which is an indication that the surface currents on the ground below the antennas are disturbed by the roof edge. Otherwise, it seems that the effect of the edge is quite minimal.

Figure 5: Dummy car model (BCM) used in the measurements

Figure 6: Azimuth (left) and longitudinal elevation (right) plane radiation pattern simulation results for transverse antenna array with 0.5 wavelength antenna spacing, 200 mm distance from the roof rear edge

Figure 7: Azimuth (left) and longitudinal elevation (right) plane radiation pattern simulation results for transverse antenna array with 5/4 wavelength antenna spacing, 200 mm distance from the roof rear edge

Figure 8 shows the comparison between measurement and simulations for the longitudinal antenna array with 0.5λ element spacing for shortest simulated distance from roof edge (in the measurement setup, the antenna were 20 mm further away from the roof edge). As can be seen, the measurement and simulation results agree very well. Similarly, Figure 9 shows the comparison between two 90° phased antenna elements with 60 mm distance from roof edge and 5/4λ element spacing, but for transverse elevation plane. Both these results show that CST MWS can be easily used to accurately simulate this kind of problems.

Figure 8: Comparison of the measured and simulated azimuthal radiation pattern results for longitudinal antenna array with 0.5 wavelength element spacing

Figure 9: Comparison of the measured and simulated longitudinal radiation pattern results for two 90 degree phased antenna elements with 5/4 wavelength element spacing, 60 mm from roof rear edge

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.