ALFORD MICROWAVE DESIGN CONSULTANTS
We specialize in filters and related devices, however, if it is passive, bilateral RF/microwave expertise you need, we can provide it.

 AMDC    Who, What & How    Diplexers    Waveguide Filters    Cavity Filters    Microelectronic Filters    Circuit Board Filters


    AMDC now represents and sells WIPL-D electromagnetic analysis and optimization software product in selected US  markets and territories.  Working through the exclusive US distributor of WIPL-D software products, WIPL-D(USA), AMDC provides support and instruction services for use of WIPL-D products to design, analyze and optimize complex microwave structures like the filters described in this website.  These EM analysis and optimization products are the BEST VALUE in the market.



         Large structures like aircraft, ships and satellite ground station antennas represent difficult EM simulation challenges. This is because traditional EM simulation methods based on volume discretization lead to near impossible demands on computation resources, especially as frequency increases.  MoM based EM simulation strategies are known to generally require reduced computation resources because surface discretization is normally employed.  WIPL-D pioneered the use of higher order basis functions on larger structural elements with a MoM based solution engine to bring the computation resource demands of larger structures within the capability widely available personal computers and workstations.
    Small, complex structures like electronic circuits and cavity filters have traditionally been simulated with volume discretization methods because the accurate modeling of such structures requires structural elements that are much smaller than a wavelength and naturally consistent with very simple basis functions.  However, very often the complexity and/or physical size of the device causes the same computation resource problems presented by large structures.  Such higher complexity electronic devices can be simulated with MoM EM strategies; but most commercial MoM tools are not fully 3D capable.
    WIPL-D offers a suite of EM analysis tools that can be used with a co-simulation strategy to efficiently simulate complex electronic devices like cavity filters.  The figure below shows a typical direct coupled cavity filter modeled in WIPL-D Pro.  Notice that many “real world” features such as the input/output coupling wire, Teflon loaded input/output connections, tuning screws, reduced size input/output resonators and flanged resonator rods can be efficiently modeled with the built-in meshing tools.Cavity Filter EM Model
    Certain filter markets like cellular telephone base stations and communications satellites place very difficult size and electrical performance requirements on electronic equipment used in these markets.  The simple in-line topology of the direct coupled resonator filter shown above may not provide the required size and electrical performance.  Such filters often require serpentine topologies and cross coupled resonators to comply with specifications.  Modeling complex topologies in WIPL-D Pro using the built-in pre-meshed objects is possible but may be tedious and time consuming.  WIPL-D Pro CAD is another product that offers direct import and automatic meshing of structures modeled with standard mechanical CAD tools.  Expeditious parallel development of the mechanical and electrical features of complex topology cavity filters can be realized using WIPL-D Pro CAD and WIPL-D Microwave Pro with a  co-simulation strategy.  The EM model shown below was produced by WIPL-D Pro CAD and represents a 5 resonator cavity filter with one cross coupled tri-section and reduced size end resonators.  

5 Resonator Cross Coupled Filter EM Model 

Normally, only a single frequency sweep analysis of the EM model is required when using a co-simulation strategy.  The resulting multi-port S parameter file can be quickly optimized in WIPL-D Microwave Pro.  The figure below shows the WIPL-D Microwave Pro equivalent circuit model for the EM model shown above; along with optimized tuning capacitor values (obtained in less than two minutes on a modern PC).

Eqivalent Circuit for Cross Coupled Filter


AMDC Contact Information    AMDC Home Page


The contents of this website are the copyrighted property of James Lyn Alford and may not be used for any other purpose without written permission
.