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COPLAN is a Design Tool
for Coplanar Circuits in the Environment of Keysight ADSTM
Introduction
CPW design technique allows to reduce the circuit size. In addition, the expensive backside processing and the difficulty via etching of microstrip technology becomes obsolete. All this leads to large cost savings for the realization of (M)MICs. Although there are many encouraging activities in CPW design, there is a lack of a complete, accurate CAD oriented CPW element library. With COPLAN FOR ADSTM, such a library of coplanar elements is now available in the EDA environment of Keysight ADS. The schematic circuit entry as well as multi-level layout generation is completely supported besides the accurate simulation of elements. An intensive verification of all library elements up to high frequencies indicates the high accuracy and great flexibility of the library. |
Library
Structure COPLAN FOR ADSTM consists of all elements necessary for the design of modern coplanar (M)MICs. CPW lines of different substrate and geometrical configurations are implemented. Further more, in version 2.3 of COPLAN, a new palette consisting of 2 to 10 coupled coplanar lines is implemented. A substrate configuration of three layers with different dielectric constants and dielectric losses is introduced. Various coplanar discontinuities from one-port, such as open and short ends over two ports, like step, gap, and bend up to four port CPW cross elements, are available. Three types of air bridges can be used as a two port element for the connection of ground planes or in combination with coplanar junctions. To complete the CPW library, lumped elements such as rectangular inductors, interdigitated and MIM capacitors, as well as thin film resistors are available. The parameters of metallic, dielectric, and resistive layers can be specified in a technology data item. The use of data items for substrate and process related parameters guarantees a maximum of design flexibility. A detailed description of all elements and their use as well as a comprehensive documentation of verifications and examples are available in the manual. |
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Background
The kernel of COPLAN FOR ADSTM is based on an accurate field-theoretical modeling in combination with a sophisticated 3D quasi-static finite difference calculation (FDM). The simulation procedure is as follows: For each element in the library, a broadband model (equivalent circuit) is introduced. The model parameters are derived from electrostatic and magnetostatic field distributions, which are calculated using a quasi-static 3D finite difference formulation for electric and magnetic potentials. Since it has been proven that coplanar structures only show marginal dispersion effects, such a quasi-static calculation is even valid for very high frequencies. The 3D-FDM
simulation takes all effects such as limited ground
planes, backside metallization, cover and bottom plates,
and losses due to finite metallization thickness into
account. In addition, all process related data, like
different dielectric and resistive layer para-meters are
auto-matically considered during the simulation and
layout generation. |
Verification
More than 100 coplanar test structures and circuits are available for the verification of COPLAN FOR ADSTM. Not only simple structures but also combinations of critical coplanar elements like bends were designed and realized on GaAs. Various passive and active circuits like filters, couplers, dividers, amplifiers, up-converters etc. have been designed, realized and verified. The comparison of simulation data with measurements in a wide frequency range indicates the high accuracy and flexibility of COPLAN FOR ADSTM. |
Layout
COPLAN FOR ADSTM supports an automated and technology dependent layout generation for all elements implemented. A so called DEFAULT foundry is integrated and allows the user to specify layer parameters, oversizes, overlaps, etc. for both simulation and layout processing. The DEFAULT foundry supports a real two metal level process with different resistivities and thicknesses for both levels. Furthermore, three dielectric layers are available for the realization of MIM capacitors as well as a resistive layer for thin film resistors. In order to meet your requirements due to the use of a certain foundry, IMST offers a customization of the library. Any custom foundry with an arbitrary number of layers can be integrated into COPLAN FOR ADSTM as a special service. Furthermore, modification of existing elements as well as implementation of new elements is possible. Requirements for Running COPLAN For running COPLAN FOR ADSTM, you must have access to the Keysight ADS environment. The library is available for LINUX as well as for Windows (PC). Since COPLAN uses Flexlm software for licensing of the features, both node-locked and floating licenses can be provided. The handling of COPLAN is as easy as it is for other standard libraries within Series IV. Never-theless, for an effi-cient use of the software, IMST´s COPLAN team offers an indivi-dual training for customers, who like to know more details about coplanar circuit design. As a customer of COPLAN FOR ADSTM you will receive full support during installation and running the software. Questions about using the software can be answerd by the help of the competent COPLAN team at the IMST. You will always get qualified support and quick response to your questions by fax or email. COPLAN FOR ADSTM will continuously be extended and improved by adding more elements and features into the library. You can take advantage of this development by ordering the latest release. Upgrades are free of charge for customers who maintain an update and support contract. Free Demo-CD and Evaluation Key Both software and manual of COPLAN FOR ADSTM are available on request. You can also order a free demo key in order to evaluate the software. Manual and more infos are on Coplan Manuals available, as well. |