Parametric blocks, whose physical behavior may be calculated from an analytical model or, alternatively in some cases, from a numerical simulation. These blocks are characterized by a set of parameters which can be modified within the CST DESIGN STUDIO™.
File blocks that are associated with a project file or data file and can only be modified by browsing for a different file or by editing the current one.
Schematic blocks which are inserted automatically into the schematic view when opening a CST MICROWAVE STUDIO®-, CST CABLE STUDIO™-, CST PCB STUDIO™-, or CST MICROSTRIPES™ project. These blocks can neither be deleted nor inserted by the user.
Constructing a system of analytical blocks, such as transmission lines, microstrip lines and rectangular waveguides including the available discontinuity models, leads to a fast solution and enables quick parameter variations over a wide range. The results, however, may be inaccurate due to the following reasons:
The quality of an analytical model is always limited. There are numerous publications dealing with the problem of finding and evaluating parameterized models for discontinuities, couplings, etc. In general, the application range of an analytical model is limited due to either the frequency range over which they are valid or restrictions for the model parameters. Even if all requirements for the proper usage of such a model are fulfilled, authors indicate a relative error of up to 10% in some cases.
A schematic design using analytical components cannot consider electromagnetic coupling between them.
A full wave electromagnetic simulator does not face these problems. Therefore, CST DESIGN STUDIO™ offers a tight interface to the most powerful 3D simulators, especially to our powerful CST MICROWAVE STUDIO® 3D electromagnetic simulation software. As far as such a simulator is concerned, the quality of the results is limited more or less by the available resources (time, memory, CPU).
To add a block to your design, drag it from the block selection tree and drop it inside the schematic view where you want to position the block. For the file blocks, a common file dialog box is displayed where you must browse for a file. In this case, the insertion will be completed if a valid file is browsed.
However, one can also create a new block by pressing the Ctrl key while dropping CST MICROWAVE STUDIO block inside the schematic view.
Each type of block is associated with a specific image (the block image) that represents a type of block inside the block selection tree and illustrates the type of a block inside the schematic view.
According to the physical model that a block implements, it has a certain number of internal ports, which are the interfaces to other blocks. For most of the types of blocks, the number of internal ports is fixed, but for some blocks, the number of internal ports depends on the contents that have been assigned by the user. The most important block with a varying number of internal ports is the CST DESIGN STUDIO block, which is a placeholder for a complete model. In contrast to internal ports, external ports represent the sources and sinks of your design, i.e., its inputs and outputs;
To connect one block to another or to an external port, choose 
Home:
Components 
Connector
or use the shortcut
'c' (for 'connect') to activate the link mode. Then,
perform two mouse clicks, one on the block's internal port
and one on either another blocks's internal port or on an external port
to establish a connection. Alternatively, you can double-click on the
highlighted internal port to start a connection.
All settings concerning a block can be performed
within the block property dialog box that can be opened by choosing 
Home:
Edit Properties
or by using the block's context menu.
For most of the blocks, a double-click inside the schematic view can alternatively
be performed. The block property dialog box consists of one or more of
the following pages whose contents change depending on the type of block:
Within the Block
Properties - Parameters dialog box the parameters describing the block's
properties (if it is a parametric block) can be edited. For microstrip-,
stripline-, and waveguide
blocks, you can also associate some of the parameters (those that are
typically common to all blocks of the given type) with a reference
block.
Within the Block
Properties - General dialog box you can browse for a different file
(if it is a file block). Some block-specific settings can also be modified
here (e..g for IBIS blocks).
Within the Block
Properties - Solver dialog box you can select the solver for the evaluation
of the block, if several different solvers are provided for this type
of block. Furthermore, you can switch on or off the Deembed
property that indicates whether the inverse physical behavior of the block
will be considered during the subsequent calculation. The solver settings
of the CST MICROWAVE STUDIO / CST
CABLE STUDIO, CST PCB
STUDIO, Library
and Microstrip / Stripline
blocks are block-specific.
Within the Block
Properties - Model dialog box you can specify model related settings
of IBIS blocks.
Within the Block
Properties - Layout dialog box you can easily modify the arrangement
of the internal ports. Consider whether turning the whole block (via 
Home:
Drawing Arrange
Rotate
Right/Rotate Left or using
a corresponding shortcut)
would lead to a better result.
Within the Block
Properties - Font dialog box you can modify font properties. Note
that only text that can be modified which is not a part of the block image.
The Block Properties - Position And Size displays the current position and size of the block inside the schematic view.
There are some block properties that you should pay particular attention to:
De-embedding
a block means considering its inverse physical behavior.
The 'Differential
Port' property checkbox enables the user to access internal port's
reference pins, denoted by a prime in the schematic view. If disabled,
all reference pins are on ground potential.
Some block types reference external files and offer features like browsing for a new file, editing the referenced project, choice of relative or absolute paths, updating file references and recovery of lost files.
Some block types have a geometrical representation in the layout view. The layout position and alignment of these blocks is determind by a common set of layout properties.