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. The two dielectric discs act as coupled resonators such that the entire device becomes a high quality band pass filter. This device has been calculated by using the Eigenmode Solver of CST MWS together with Modal Analysis. In combination with the transient solver and AR filter analysis it is an ideal tool for filter design.
Figure 1: Filter structure
View of the filter structure. Purple: Dielectric discs (permittivity of 38). Blue: Metal parts. Light gray: Resonator chamber, filled with air.
Figure 2: S-Parameters
S-Parameters calculated with Modal Analysis in the band pass region. Calculation time: 2 minutes and 40 seconds on a Pentium PII 400 MHz.
Figure 3: 3D vector plot of the first mode (magnetic field) at 4.079 GHz.
Figure 4: 3D vector plot of the second mode (magnetic field) at 4.079 GHz.
Figure 5: 3D vector plot of the third mode (magnetic field) at 4.577 GHz
This mode is related to the first peak in the spectrum shown above. Please notify, that the S-Parameters have been calculated with external coupling, whereas the modes have been calculated without external coupling. This explains the frequency shift of approx. 20 MHz.
Figure 6: 3D vector plot of the fourth mode (magnetic field) at 4.604 GHz
It is related to the second peak of the spectrum shown above. Again the frequency shift of approx. 20 MHz has been caused by external coupling.
CST Article "Modal Analysis of a Dielectric 2 Port Filter"
last modified 15. Mar 2010 9:49
printed 15. Mar 2010 9:49, Article ID 30
URL:
All rights reserved.
Without prior written permission of CST, no part of this publication may be
reproduced by any method, be stored or transferred into an electronic data processing system, neither mechanical or by any other method.
Article ID: 30
Last modified: 15. Mar 2010 9:49
Other Articles
CST EM STUDIO™'s Electrostatic Solver can be used to establish electric breakdown fields in X-Ray devices. A STEP model of the device was imported via CST EMS's comprehensive CAD Interface.
Read full article..
Radio Frequency Identification Systems (RFID) are widely used and allow advanced solutions for a variety of applications in the area of authentication, ticketing, access control, supply management, parking, payment, vending,etc. The example presented here is a RFID Readercoil "P81" from Legic Ident Systems and was modeled and solved using the frequency domain solver of CST MICROWAVE STUDIO® (CST MWS). The sensitivity of the computed complex input impedance with respect to substrate tolerances is computed and was compared to measurement data.
Read full article..
This article demonstrates the application of CST MICROWAVE STUDIO® (CST MWS) to the analysis of large reflector feed arrays. An array consisting of 19 elements was simulated but a larger array of more than 100 elements may also be simulated since the memory scaling with mesh cells in CST MWS is almost linear. The simultaneous excitation feature in CST MWS was applied to obtain farfield patterns in just a single simulation. A parameter sweep was also carried out to obtain the S-Parameters as a funtion of element feeding postion.
Read full article..
This article demonstrates the simulatenous excitation of arbitrary waveforms at a number of different ports. A noise source in the form of a loop circuit is place above an IC package and the influence of the noise source on the transmission of differential signals in the IC feed tranmssion lines is investigated. Two frequency ranges were simulated, 1-10 GHz and 1-20 GHz. The simulations were carried out using the simultaneous excitation feature in CST MICROWAVE STUDIO® (CST MWS).
Read full article..
A portion of a backplane, designed with the Cadence Allegro® layout tool, is imported into CST MICROWAVE STUDIO®. This section consists of a differential pair with vias which go through the board. The structure was analyzed in Microwave Studio. The simulation results demonstrate the impact of backdrilling the signal vias to improve the signal integrity performance. A detailed SPICE model of the transmission path is created and its accuracy is verified.
Read full article..