This article describes the use of CST MICROWAVE STUDIO® (CST MWS) to solve a coupling problem in a mixed analog – digital multilayer PCB card. The work was carried out by Mr. Zeev Iluz, Alvarion, Ltd.

The PCB is made of 14 layers and contains several A/D convertors, which operate at f=20MHz. Each A/D has 12 digital outputs and the traces to the FPGA are routed in two different layers. After manufacturing and testing the first prototype by transmitting the periodic digital pulses from the first A/D, a high signal in the second A/D analog port was detected [Figure 1], which shows a strong coupling from the first A/D (output traces) to the second A/D (input trace).

The second A/D analog trace is in the top layer while the first A/D digital traces are in internal layers. All layers are separated by a metal ground and an isolation higher then 80dB is expected. However, in figure 1 it can be seen that the isolation between the traces is about 80dB(left)-40dB(right)=40dB. This is a very high value that indicates there is a poor isolation despite the presence of the metal ground.

All 12 ports from the A/D input traces were simulated. The S-Parameters in figure 4 which shows that the traces 6,10,11 and 12 have a high coupling to the A/D output compared to all other traces, whereas trace 11 has 40dB more coupling than the other traces. From these S-Parameter results we are now able to locate the trace 11, which has a strong coupling to the A/D output (port 26).

All the 12 traces from the A/D (input) were terminated with 50 ohm ports at both ends. In order to read the coupling to the second A/D output, this was terminated with a 50 ohm port as well (port 26).

• 0 to 360 degree AZ
• +/- 90 degree EL
• Dual-axis high-resolution antenna positioner
• Two 10-Foot Precision SMA measurement cables
• Includes DAMS Antenna Measurement Studio Pro
• Complete package includes all accessories

The layers thickness and R, L, C components were defined. Gap source ports between the outputs of the first A/D to the FPGA and the second A/D input were easily defined in CST ODB++ import software. Since only the A/D connection are the point of interest, only the relevant area of the board was imported [Figure 3].

The great variety of devices in need of electromagnetic simulation has led, over the years, to the development of an almost as great variety of solutions. For each device, there is probably one method that provides the quickest, most accurate results. The goal of this paper is to discuss applications for which time domain simulations are not only well suited, but perhaps even the only successfully applicable approach.

Eight resonator folded combline filter calculated with 200 frequency steps:
Total computation time: 11min 44 sec with “Normal” sweep
Total computation time: 1min 55 sec with “Adaptive” sweep
The computation for 1000 frequency steps with “Adaptive” sweep is 2 min 5 sec
Pentium IV 2.66GHZ 768MB RAM
Please note: higher order modes have been taken into account!

Waveguide diplexer with a t-junction (septum)vcalculated with 300 frequency steps:
Total computation time: 59 sec with “Normal” sweep
Total computation time: 11 sec with “Adaptive” sweep
The computation for 1000 frequency steps with “Adaptive” sweep is 12 sec
Pentium IV 2.66GHZ 768MB RAM

Waffle iron filter calculated with 300 frequency steps:
Total computation time: 21 sec with “Normal” sweep
Total computation time: 7 sec with “Adaptive” sweep
The computation for 1000 frequency steps with “Adaptive” sweep is 8 sec
Pentium IV 2.66GHZ 768MB RAM
Please note: higher order modes have been taken into account!

As an example the synthesis of the coupling matrix of a 12-th order filter is shown. be found. The return loss level is -30dB, the frequency band 10.8GHz-11GHz, two imaginary zeros at 11.02GHz and 11.05GHz and one pair of complex zeros to equalize the group delay response.

As an example the synthesis of the coupling matrix of a 8-th order filer is shown. TThe return loss level is -40dB, the frequency band 2.4GHz-2.48GHz, two imaginary zeros at 2.39GHz and 2.38GHz. T

CST DESIGN ENVIRONMENT™ is the access point to CST STUDIO SUITE™ . In this frame work projects created with the different electromagnetic simulation softwares in CST STUDIO SUITE™ can be opened simultaneously.

The CST DESIGN ENVIRONMENT™(CST DE) user interface is the common pre-processor for all members of the CST STUDIO SUITE™. The 3D tools CST MICROWAVE STUDIO®(CST MWS), CST EM STUDIO®(CST EMS) and CST PARTICLE STUDIO®(CST PS) rely on the same technology that previously founded CST MWS reputation for offering the user friendliest interface on the market:

• An intuitive, native Windows based GUI, makes beginners immediately feel at ease with the program.
• New users are escorted through the program by a quick start guide and a collection of online tutorials.
• The advanced ACIS kernel enables amazingly easy CAD modelling.
• A strong graphic feedback further simplifies device definition.
• Simulation runs and postprocessing can be controlled, via OLE automation server, using applications such as Excel, Matlab, and PowerPoint.

SATSOFT is used for communication satellite antenna design, analysis, and coverage planning. Quickly assess antenna coverage and gain, conduct antenna trade studies, develop shaped beam and multibeam antenna designs, and perform other satellite payload engineering tasks. SATSOFT was written for the systems engineer as well as the antenna specialist. Its graphical user interface was designed to enable users with even a basic knowledge of antennas to use the software productively. Advanced tools will appeal to the antenna specialist. If you need software to model satellite antennas, for GEO, LEO or MEO constellations, SATSOFT was written for you. Please see our Products page for more information on SATSOFT and the options that are currently available.

µWave Wizard is a design tool using the well-known fast and accurate Mode-Matching technique. This method is particularly suitable for simulation and optimization of passive microwave systems and components, including antennas. The mode matching method (MM) and their derivatives (i.e. the fast hybrid MM/boundary contour and the MM/2D-finite-element method) is the only method capable of simultaneously offering fastest processing speed and highest accuracy.

Mician’s software developers' secret for speed is to avoid the use of time consuming 3D solvers wherever possible and to focus on applying the Mode-Matching Technique and its derivatives instead, even on structures that at first glance seem to be suited for 3D solvers only. Yet, a 3D FEM solver on element level is available within the µWave Wizard for structures with very complex geometries or with features not feasible to be implemented in MM.

In addition to its fast and powerful numerical methods, the µWave Wizard offers an appealing and ergonomic GUI that enables flexibility and openness. The consequent implementation of the latest field theoretical and mathema typical approaches is Mician's challenge for the continuous enhancements of the µWave Wizard.

Waveguide diplexer calculated with 300 frequency steps:
Total computation time: 45 sec with “Normal” sweep
Total computation time: 8 sec with “Adaptive” sweep
The computation for 1000 frequency steps with “Adaptive” sweep is 10 sec
Pentium IV 2.66GHZ 768MB RAM
Please note: higher order modes have been taken into account!

Corrugated horn antenna calculated with 200 frequency steps:
Total computation time: 44 sec with “Normal” sweep
Total computation time: 14 sec with “Adaptive” sweep
The computation for 1000 frequency steps with “Adaptive” sweep is 15 sec
Pentium IV 2.66GHZ 768MB RAM
Please note: higher order modes have been taken into account! The calculation time is S11 for the entire frequency range and includes the calculation of the farfield for the center frequency too.

The Combline Filters Synthesis Wizard (CFSW) allows a fast synthesis and optimization of narrow- and broadband combline pass band filters by using the mode-matching technique for the multimodal computation. The simulation is provided by Mician's Mirowave Wizard. The CFSW uses a novel technique for the synthesis of the coupling coefficients and a new efficient optimization method.
The filters can be of type inline or folded. In case a of narrow band filter the cavities are separated by irises where each iris can include finite radii for milling purposes. In case of a broadband filter the design consists of posts only.

After starting CFSW the main window appears as shown in Fig.2. The window allows the setup of the filter specifications. The design of the filter is straight forward. From the users side it is required to go through all tabs and to add the required parameters to the entries until all check marks are green.

The DEPA50-4000/5 power amplifier is ideal for broadband applications such as instrumentation or 802.16 , WiFi, WiMax, RFID or Software Defined Radios. This amplifier utilizes the latest ultra linear highly efficient GaN devices. The DEPA50-4000/5 offers an ultra small size and operates from a single supply Class AB or Class A operation
Instantaneous ultra broadband
RF Power control & Blanking
Low harmonic content and spurious output
Suitable for CW/FM/PM/AM/Digital modulation

Antenna Magus is a new software tool to help engineers accelerate the antenna design and modelling process. It has a huge database of designed antennas which can be exported to CST MICROWAVE STUDIO® for further analysis and optimization. This simplifies the day-to-day work of antenna designers ensuring that more projects are completed within specification and on time.

Antenna Magus offers an extensive database of antennas which is easily searchable. It not only highlights the unique characteristics of an antenna, but also gives other general information. This helps engineers find and select antennas according to given requirements as well as compare relevant information between antennas.

Its feature set is targeted at aiding engineers get to the customisation phase of an antenna design quickly and reliably. Validated, parametric models of the initial design are exported seamlessly into CST MICROWAVE STUDIO, where in-depth analysis and optimization can be performed.

It is expected that Antenna Magus will become an invaluable aid to antenna design engineers, to EMC engineers requiring antenna models and to system integrators who require antenna models for antenna placement studies.

CONSULTANCY TURNKEY PROJECTS AntennEM Communication

CST CABLE STUDIO™ (CST CS) is dedicated to the three-dimensional analysis of signal integrity (SI), conducted emission (CE), radiated emission (RE), and electromagnetic susceptibility (EMS) of complex cable structures in electrically large systems. It provides powerful import filters from popular MCAD and ECAD tools for smooth integration into the industrial workflow.

With its main focus on automotive and aerospace applications, CST CS is equipped with enhanced visualization capabilities in order to interactively highlight selected signals or cables in both the 3D graphic view and the 2D schematic view. Visual positioning checks of connectors and cables are easily possible. Information about which cable carries which signal or which wires are connected to which connector pins can be directly accessed in the CST CS navigation tree.

CST MICROSTRIPES™ is a powerful 3D electromagnetic simulation tool, used extensively for solving challenging radiation problems including complex antenna structures, installed performance, EMC/EMI/E3 issues.

CST MPHYSICS STUDIO™ (CST MPS) is a powerful and easy-to-use tool for thermal and mechanical stress analysis. CST MPS is fully integrated into CST STUDIO SUITE and this enables coupled EM-multiphysics simulation with other tools such as CST MICROWAVE STUDIO.

CST PARTICLE STUDIO® (CST PS) is a specialist tool for the fast and accurate analysis of charged particle dynamics in 3D electromagnetic fields. This software tool is based on the multi-purpose 3D EM modules in CST STUDIO SUITE™ such as the CST EM STUDIO® electro and magnetostatic solver. It is fully embedded in CST DESIGN ENVIRONMENT, thus benefitting from its intuitive modelling capabilities and powerful import interfaces. CST PS is based on the knowledge, research and development that went into the algorithms used in the MAFIA-4 simulation package.

CST PCB STUDIO™ (CST PCBS) is a specialist tool for signal integrity (SI), power integrity (PI), and electromagnetic compatibility (EMC) analysis on printed circuit boards (PCB). It integrates easily into your design flow by providing powerful import filters for popular EDA tools from Cadence, Mentor Graphics, Zuken, and Altium. Prior to modeling and simulation, the imported layout is automatically checked in order to correct potential geometric errors.

The intuitive workflow of CST PCBS and its accurate and modern simulation techniques allow for investigations of any kind of PCBs, from single-layer boards up to multi-layer high-speed designs. Effects like resonances, reflections, crosstalk, power/ground bounce and simultaneous switching noise (SSN) can be simulated at any stage of product development, from pre-layout to post-layout phase.

The focus of the µWave Wizard is speed and accuracy for simulation of passivce waveguide components e.g. filter, multi- and diplexer, coupler, horn antennas, feeding networks, etc. The next examples shows the capability of the µWave Wizard in terms of simualtion speed.