what is MultiLib ?   
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What is MultiLib ?
Introduction:
  • MultiLibTM is a new state-of-the-art model library, which includes all standard elements for analog high-frequency multi-layered circuit designs, such as LTCCs, PCBs and others.
  • The MultiLibTM modeler library employs the User-Compiled Analog Model interface of Agilents ADS and is thus fully integrated in Agilents ADS. All elements are available by the well-known component-palette procedure as in Agilents ADS .
  • Automatic layout generation is supported, too. The MultiLibTM 3D viewer for visualization and verification of complex shapes complements it.
  • The user has the flexibility to combine the MultiLibTM library to his own User-Compiled Models and thus to the Agilents ADS product itself.
  • MultiLibTM is available for Agilents ADS on WindowsTM.
  • Like other Agilent ADS features, MultiLibTM uses the flexlm license manager, which warrants a flexible and easy license management.


Modelling:

A full 3D-FDTD (Finite Differences in Time Domain) simulation kernel allows to calculate real 3D elements, which results in the most exact models possible for these devices.

All simulation results will be stored in a cache before these are returned to Agilents ADS circuit simulator. The fast access on earlier calculated elements (lookup table capability) makes it ideal to tune and optimize element geometries as other libraries in Agilents ADS.
 
Data Items:

The basis of the MultiLibTM handling capabilities are few, very easy and flexible Data Items, which describe the structure of multi-layered LTCC technologies. These have to be created once for a certain multi-layer technology and can be used for all MultiLibTM elements.

There are no principal limitations for the number of layers and thus allows the simulation of a broad range of LTCC elements.
The unique library results from:
  • Our vast experience in MMIC design
  • The development of planar and multi layer circuits
  • The in house hybrid and the new in house LTCC prototyping technology
  • Modelling & Simulation tools experience with EmpireTM and CoplanTM and Topas
  • The working experience with Agilents ADS and its model interfaces (results from Coplan/Topas-software)
  • Special multi-layer circuit simulation knowledge with Empire
Examples:

A LTCC multi-layered coupler is used for describing the new MultiLibTM features. The associated data items, which describe the multi-layered structure, are displayed next to data items above. For example, the item Subst1 defines the order of the different layers, which can be metal, tape, or ground layer. The cross sections of single and coupled lines are defined by line types. As seen above, a schematic drawing is depicted in the Agilent ADS environment. On the left, the MultiLibTM data items and elements can be selected from the palette. E.g., the via model includes pads, ground holes, and a selectable number of connections in different layers. A wide range of vertically and horizontally coupled elements like lines, shorts, opens, and bends are available, too.
The schematic shows a four port coupler with one port terminated by a resistive load. By starting the simulation all elements, which are not already available in the cache, will be modeled using a 3D FDTD solver. An automatically generated layout is shown in the figure.
The three-dimensional realistic image gives an impression of the complexity of the simply generated multi-layer circuit.
A five stage triplate filter built from lines, tees, steps, opens, and coupled opens with via fences is shown. The segmentation procedure will reduce simulation time drastically compared to a 3D simulation of the whole structure.
In the last example a design of a power amplifier is displayed in a 3D view. The employed MultiLibTM elements are via holes, block capacitors & inductors, tees and rolled-up coupled lines. The chip is embedded into a grounded cavity.