• 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

Transient Co-Simulation of a Hybrid Ring Mixer with Matching Network

The integration of active components and system level simulation is an outstanding feature for users of CST STUDIO SUITE®. In this article, a 180° Hybrid junction is employed in the popular mixer topology. The Hybrid itself is simulated in CST MICROWAVE STUDIO® (CST MWS) and the diodes and matching circuits are incorporated in CST DESIGN STUDIO™ (CST DS). Simulation results compare well with measurements and optimization of the matching networks within CST DS is used to improve the overall performance.

Figure 1: Full 3D CST MWS Model of the hybrid Mixer with CST DS Diodes

The 3D model simulated in CST MWS is shown in Fig. 1. As a postprocessing step, the diodes were added to the model using CST DS and simulations were performed to obtain S-Parameter, time domain waveforms, and frequency domain spectral content....

Figure 2: 3D Simulation S-Parameter results

Figure 2 shows the simulated S-parameters of the 180° Hybrid junction.

Figure 3: Animated 3D Surface Current Plot

An animation of the surface current at 2.8 GHz is shown in figure 3. This animation can be created effortlessly with the aid of the video animation macro in CST MWS.

Figure 4: Schematic View of the CST MWS / CST DS Co-Simulation

The diodes for mixing and the package parasitic components were included in CST DS as shown in Fig. 4.

Figure 5: Simulated (Green) and Measured (Red) S-parameter results from CST DS Cosimulation

Figure 6: Simulated (Green) and Measured (Red) S-parameter results from CST DS Cosimulation

The aforementioned results are shown in Figs. 5 - 8. Figures 5 and 6 show good correlation between measured and simulated results.

Figure 7: Time Domain Voltage Waveform at IF Port

As a confirmation of proper operation, the time domain voltage waveform is shown in Fig. 7. The IF frequency was chosen to be very low relative to the RF and LO to facilitate its identification in the time domain waveforms. It should be noted that the design frequency of the 180° Hybrid is 2.8 GHz and the LO frequency should match. The proper operating conditions are shown in Fig. 8 along with the simulated spectral content at the IF port.

Figure 8: Frequency Domain Spectral Content

As shown in Fig. 8, the output spectrum is cluttered with harmonics of, and dominated by, the RF and LO inputs.

Figure 9: CST DS Circuit with Matching Network

The performance can be improved by including impedance matching networks at all three ports as shown in Fig. 9. By inspecting the S-parameters of Figs. 5 and 6, one can obtain a decent starting point for the values of the matching elements, however, all three ports must be matched simultaneously at three different frequencies. Such a task would prove difficult and time consuming. Instead, the built in optimizer of CST DS was used to generate the optimal solution. The optimized values are also shown in Fig. 9 and the optimized S-parameters are in Fig. 10.

Figure 10: S-Parameters after DS Matching

It is apparent from Fig. 10 that the optimization worked quite well, providing over 60 dB return loss at all ports. Re-simulating the spectral content at the IF port generated the plot shown in Fig. 11.

Figure 11: Simulated spectral content at IF port after matching in DS

Inspecting Fig. 11 shows that the matching network dramatically improved the performance of the mixer. The output spectrum is now dominated by the IF and the RF/LO and their harmonics are supressed.

In this article, it was shown how CST MWS and CST DS can be combined to analyze and optimize the design of a 180° Hybrid mixer. Comparisons with measured results were made and found to correlate well. Optimized impedance matching networks at the input and output ports provided a simultaneous solution and improved mixer performance.

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.