Filters

Filters are highly resonant structures that can be found in any communication channel. The frequency domain solvers within CST MICROWAVE STUDIO® are ideal for their design and analysis. The eigenmode solver provides a specialized solution for cavity design. Both solvers support curved tetrahedral elements, which means that curved structures can be analyzed more accurately and efficiently.

A key design step is the tuning of a filter, which might be a challenge because of the high sensitivity of the tuning parts. CST provides several unique features to make the design process as simple as possible. An estimation of the sensitivity of the filter response to small geometric or material property variation can be obtained from a single simulation. In addition EM/circuit co-simulation allows for a very efficient manual tuning process.

All Filters All Resonators

All Articles

CST FilterDesigner 2D Flyer

CST FilterDesigner 2D Flyer Document type
FilterDesigner 2D is a fully-integrated tool for the design and synthesis of planar and circuit filters in CST®STUDIO SUITE®. Built on Nuhertz Technologies’ well-reputed and mature technology, FilterDesigner 2D can be used to quickly select an appropriate filter type and generate a simulation-ready circuit or 3D model. Read full article..

8th Order Dielectric Resonator Filter with Three Asymmetric Transmission Zeroes

8th Order Dielectric Resonator Filter with Three Asymmetric Transmission Zeroes Document type
The dielectric resonator fi lter (Figure 1) is a high-performance filter design which is well-suited for applications where compactness and power are important. These sorts of filters are widely used in communication systems – for example, in mobile phone base-stations. The number of independent design parameters that need to be optimized makes higher-order dielectric resonator filters challenging to tune. Simulation software can therefore be used to make it easier to design and tune these filters. Read full article..

RF Breakdown Analysis in Space Applications

RF Breakdown Analysis in Space Applications Document type
Devices in the output section of a satellite payload, including filters and multiplexers are subject to high RF power. This could lead to RF breakdown, which may render the specific device useless and, in the end, degrades the reliability of the satellite. Therefore all space high power devices have to be analyzed with regards to their breakdown behavior. This application note shows how CST STUDIO SUITE® and SPARK3D® can be used to investigate these effects via simulation. Read full article..

Simulation and Measurement: Complementary Design Tools

Simulation and Measurement: Complementary Design Tools
The usual aim of electromagnetic simulation in design is to lower the number of prototypes to reduce costs and time to market. However, this is only possible when the EM simulator is given the correct input data that accurately represents the physical device. Then an excellent agreement between simulation and measurement can be expected. There are many possible causes of discrepancies between the two, including geometric differences (over-etching, over-milling, rounded corners), material properties (anisotropic dielectrics, surface roughness), installed performance (surrounding structures) and feed discrepancies (connector modeling). This webinar will explore the relationship between simulation, using CST STUDIO SUITE®, and measurement, and explain what each domain is best suited for. In some situations measurement can be difficult to perform while simulation is simpler, and vice versa. Simulation allows many variations on a design to be investigated, using techniques such as parameter sweeps, sensitivity and yield analysis. The webinar will also demonstrate how simulation can be used for what-if analysis and feasibility studies at early stage of design before first prototypes. Finally, the use of measured data to calibrate simulation will be shown. This is useful for hard-to-model phenomena like surface roughness or for the modeling of low-cost adapters. Read full article..

Modeling and Simulation of Metamaterial-Based Devices for Industrial Applications

Modeling and Simulation of Metamaterial-Based Devices for Industrial Applications
The subject of metamaterials has rapidly grown over the past few years from a hot topic of academic research to a field with interesting and novel industrial applications. The exotic properties of these metamaterials include negative or low values of permittivity, permeability and refractive index, allowing engineers to manipulate the material’s intrinsic parameters to control the propagation of electromagnetic waves. Some recent industrial applications have seen metamaterial transmission lines being used in broadband filters, multiband components, dual-band tags for UHF-RFID and sensors. The metamaterial-based waveguide structures, such as composite right/left-handed (CRLH) structures, have led to interesting applications of waveguide miniaturization and novel coupler design. Metamaterial-inspired antenna design has produced reflex-cavity antennas with low-profile, high gain, beam steering and frequency agility. Read full article..

Test Equipment Plus develops high-performance custom filters with CST MICROWAVE STUDIO

Test Equipment Plus develops high-performance custom filters with CST MICROWAVE STUDIO Document type
The Signal Hound® product line from Test Equipment Plus comprises a series of compact, lightweight, and affordable spectrum analyzers. The Signal Hound equipment is built on the design philosophy of maximizing performance while minimizing cost, and as well as having a wide range of applications for general engineering labs, it has also found success in fields ranging from telecoms and spectrum monitoring to aerospace and defense. Read full article..

C-Band On-Axis Coupled Standing Wave Linear Accelerator

C-Band On-Axis Coupled Standing Wave Linear Accelerator
Linear Accelerators (Linacs) are widely employed in accelerator facilities. Linear acceleration is the method of choice for light particles as synchrotron radiation effects limit the usability of circular accelerators for these particles. Industrial applications require compact linacs for the acceleration of electrons with target energy in the range between 1 and 25 MeV. CST MWS and PS can be used to investigate the high frequency behaviour of linac structures as well as the interaction between particles and the accelerating field. Read full article..

Intelligent Representation of Anechoic Chamber Wall Cuts Electromagnetic Simulation Time 95%

Intelligent Representation of Anechoic Chamber Wall Cuts Electromagnetic Simulation Time 95%
Electromagnetic simulation of anechoic chambers is a very difficult task. Gwenaël Dun, R&D Engineer for Siepel, used a variety of different electromagnetic simulation tools to address this challenge in the past but ran into problems with both poor accuracy and long compute times. He then worked with the developers of CST MICROSTRIPES™ electromagnetic simulation software, to implement a feature that makes it possible to model the ferrite absorbers used in the chamber as a boundary condition rather than part of the computational domain. This change made it possible to increase mesh size by a factor of 15, reducing compute time by more than 95%. The simulation results provided a near-perfect match to physical testing. Read full article..

Nanophotonics and integrated optics - Photonic Crystal Cavities

Nanophotonics and integrated optics - Photonic Crystal Cavities Document type
This whitepaper gives a general overview on different concepts of photonic crystal cavities. Important figures such as the transmission, the mode volume and the quality factor are discussed. The presented information will help the reader to decide which type of photonic crystal cavities will be most suited for the application in view. A design example for a WDM channel filter is given in order to illustrate the design process for a photonic crystal cavity. Furthermore two experimental examples from recent research are shown to demonstrate the wide range of applications in which photonic crystal cavities could be used. Read full article..

A Multiphysics Approach to Magnetron and Microwave Oven Design

A Multiphysics Approach to Magnetron and Microwave Oven Design Document type
The magnetrons used in microwave ovens operate on the same frequency band as Wi-Fi equipment, and the radiation they release can interfere with the operation of wireless networks. This paper presents a multiphysics simulation of a magnetron using CST STUDIO SUITE®, with the aim of testing the electrical, magnetic, thermal and mechanical characteristics of a low-interference magnetron design. The simulation results are then compared to measurements made experimentally, and the two sets of results are shown to be in good agreement. Read full article..

A Polarisation Independent Bandpass FSS

A Polarisation Independent Bandpass FSS
This application note describes the use of CST MICROWAVE STUDIO® in optimising the geometry of a free standing nested annular slot type Frequency Selective Surface (FSS). An isolation of better than 20 dB between the 316.5-325.5 GHz and 349.5-358.5 frequency bands was achieved in both the TE and TM planes for a 45 degree incident plane wave, while the insertion loss was below 1 dB. Read full article..

Simulation of Photonic Crystal Cavities

Simulation of Photonic Crystal Cavities
This article demonstrates how properties of the resonant modes of photonic crystal (PhC) point defect cavities are obtained from transient solver simulations using CST MICROWAVE STUDIO®. In this example a single point defect in a triangular lattice of air holes in a high refractive index slab is used. Properties of particular interest are: the resonance frequency, intrinsic Q factor and field distribution of the resonant modes. The cavity is excited using discrete ports, and the spectral features are recorded with point probes. The Q factor is determined from the energy decay rate and using auto regressive filtering. 2D and 3D field monitors record the field distributions. Read full article..

Characterization of Photonic Structures with CST MICROWAVE STUDIO

Characterization of Photonic Structures with CST MICROWAVE STUDIO Document type
Stefan Prorok, Hamburg University of Technology We present an overview of our current research activities in silicon photonics and thermal barrier coatings. Doing so, we will comment on how CST Microwave Studio can be used to design strip waveguides, micro ring resonators, as well as 2-D and 3-D photonic crystal structures. Particularly we will concentrate on the discussion of photonic crystal micro cavities which can be used as electro-optic modulators. It will be shown that MWS provides all the functionality to optimize and characterize optical micro cavities. The appearance of resonant modes is adjusted through eigenmode calculation of the photonic crystal waveguide modes. Time domain simulation with discrete port excitation is applied to calculate the intrinsic Q-factor of the cavity. Waveguide ports are used to model experimental conditions of excitation with strip waveguide modes. Field monitors help to understand the mechanism of energy loss from the cavity. The simulation results are compared to measurements on fabricated structures. As possible application we will show a hybrid silicon organic hetero structure cavity for GHz electro-optic modulation. Read full article..

Designing a Band Notch Filter for a UWB Antenna Using CST MWS

Designing a Band Notch Filter for a UWB Antenna Using CST MWS Document type
Ad Reniers, Technical University Eindhoven High-data-rate wireless communications need wide bandwidths. In the Ultra-Wideband (UWB) frequency band from 3.1 GHz to 10.6 GHz, information may be spread over a large bandwidth at low power levels thus creating the possibility to share the spectrum with other users. To prevent interference with existing wireless systems, like IEEE 802.11a WLAN, stop band characteristics are required from 5 GHz to 6 GHz*. The notch filter function is designed in a low-cost circular planar dipole antenna based on the ‘two-penny’ dipole. To achieve the required specifications for this notch function we used first the CST optimizer. After that we optimized systematic the design. In this presentation we want to show the results of both approaches to achieve a maximum result and try to understand the working of this notch and spur function in this compact UWB antenna. * Paper: Low-cost, compact UWB antenna with frequency band-notch function. H.J. Visser. Read full article..

EM Simulation of a 6.7 GHz Coaxial Bragg Reflector

EM Simulation of a 6.7 GHz Coaxial Bragg Reflector
The Bragg Reflector implemented in the coaxial technology is an example for setting up simulations of periodic structures. The simulation is performed with CST MICROWAVE STUDIO® and compared to measurements. Read full article..

Thermal Analysis of a Two-Cavity Dual-Mode Bandpass Filter

Thermal Analysis of a Two-Cavity Dual-Mode Bandpass Filter
The CST EM STUDIO™ Thermal Solver has been applied to simulate the temperature distribution of a dual-mode filter. The current density distribution inside the lossy conductive metals is precomputed by CST MICROWAVE STUDIO® acting as the thermal source. Read full article..

Six-Pole Band-pass filter with Single Cross-Coupling

Six-Pole Band-pass filter with Single Cross-Coupling
Tuning of a coupled-resonator filter is performed in this article by using the group delay response of the input reflection coefficient of sequentially tuned resonators containing all the information necessary to design and tune filters. To achieve high out-of-band rejection losses a single transmission zero is introduced producing a pair of finite frequency poles. CST MICROWAVE STUDIO® is used to optimize and/or tune the bandpass filter resonse in a complete model by applying the new, fast MOR-Frequency Domain Solver. To speed-up the tuning process the entire model is split up into several sections and recombined in CST DESIGN STUDIO™ to get the overall filter response. Read full article..

GSM/DCS Dual Antenna Switch Module (ASM)

GSM/DCS Dual Antenna Switch Module (ASM)
This structure for mobile communication in LTCC technology combines a diplexer for the GSM and DCS frequency bands with a low pass filter for each band. Read full article..

Bandpass Waveguide Filter with Dual Mode Cavities

Bandpass Waveguide Filter with Dual Mode Cavities
This waveguide filter has been simulated with CST MICROWAVE STUDIO® general purpose frequency domain solver applying a tetrahedral mesh. Read full article..

Dichroic Filter

Dichroic Filter
The dichroic filter is an example for setting up simulations of frequency selective surfaces. The simulation is performed with CST MICROWAVE STUDIO® and compared to measurements. Read full article..

Photonic Band Gap Structure for a Particle Accelerator

Photonic Band Gap Structure for a Particle Accelerator
This application has been succesfully simulated using the powerful Eigenmode Solver in CST MICROWAVE STUDIO® with the aid of the Modal Analysis Module. Read full article..

Magnetron and Microwave Oven Design to Solve Wi-Fi - Interference Issues

Magnetron and Microwave Oven Design to Solve Wi-Fi - Interference Issues
This article describes how the different modules of CST STUDIO SUITE® can be used to aid the complete path of a magnetron and microwave oven design. Starting from the analysis of the interaction region in CST PARTICLE STUDIO®, continuing with the electrostatic and magnetostaic field evaluation in CST EM STUDIO®, further evaluating the field distributions inside the oven in CST MICROWAVE STUDIO® and finally leading to a temperature and deformation investigation in CST MPHYSICS STUDIO®. Read full article..

Klystron Output Resonator - Particle-in-Cell (PIC) Simulation

Klystron Output Resonator - Particle-in-Cell (PIC) Simulation
This article shows the simulation of a klystron output resonator. The simulation was performed using the Particle in Cell (PIC) code of CST PARTICLE STUDIO™. The PIC code is embedded in the transient solver of CST MICROWAVE STUDIO® and benefits therefore from a mature environment. Read full article..

Microstrip Bandstop and Lowpass Filters

Microstrip Bandstop and Lowpass Filters
New, compact configurations for RF/microwave bandstop and lowpass filters are presented. Compact footprints are achieved by folding the transmission lines in a microstrip platform. The effect of mutual coupling between the transmission lines, curved line sections, interconnecting lengths of the sections are taken into account to obtain the network parameters for the folded line filters. The folded line filters have practical dimensions for a wide range of electrical specifications, making physical implementation realizable. The filter designs have been validated by using full wave 3D EM simulation using CST MICROWAVE STUDIO®, as well as by comparison with the measurements. The new designs presented should prove useful for a host of embedded passive and RFIC applications in the 1-10 GHz range. Read full article..

Five-Section Microstrip Hairpin-Filter

Five-Section Microstrip Hairpin-Filter
The example design is a classic hairpin filter with a bandwidth of 3.6 to 4.3 GHz. The hairpin filter was designed for a return loss better than -20dB across the band. CST DESIGN STUDIO™ was used to design and tune the filter, the resulting layout was then verfied with the 3D- EM simulation software CST MICROWAVE STUDIO®. Read full article..

Modal Analysis of a Dielectric 2 Port Filter

Modal Analysis of a Dielectric 2 Port Filter
Shown is the discretised model of a dielectric two circuit filter with coaxial input and output couplers. Read full article..

Benchmark MEE 1997

Benchmark  MEE  1997
The dual mode filter was developed, measured, and simulated by ESA (European Space Agency). Read full article..

Two-Cavity Monotron Particle in Cell (PIC) Simulation

Two-Cavity Monotron Particle in Cell (PIC) Simulation
A monotron is a simple microwave tube which converts DC energy into RF energy. The simulation of such a two-cavity monotron with CST PARTICLE STUDIO® is performed and compared to published results. Read full article..

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