Preface

These days, for the designing of high-frequency circuits, the high frequency simulator
(such as electromagnetism analyzer) is being utilized quite often. In such cases, the
simulation is often conducted by importing the circuit design data (DXF Data).
However, it is not unusual for us to hear the problems that DXF data do not properly
function and, considerable time is wasted for the correction of these problems.
The same types of the problems occur when converting the imported DXF date into
the appropriate data for the board making machine. Let us explain here about the
details of such problems and how to correct them.



What is DXF Data ?

DXF Data are the data developed by the well known AutoCAD company called Autodesk.
CAD data of AutoCAD are called "DWG". They are the DXF (Drawing Exchange Format )
which are developed in order to enable the different types of CAD to utilize those data.

About the versions of DXF files

There are various types of DXF as listed below.

	When using DXF files, you must to be very careful about the following aspects.
	-	When saving files by AutoCAD, you have to designate the appropriate version of DXF file so that the data can be imported onto your software. Depending of the types of board making machine or electromagnetism simulation software, there are some cases where DXF files can not be imported. Particularly, as there are many changes for AC1009 and AC1012, you have to make sure that you are suing appropriate type of DXF file version.
	-	In order to complete the supporting tasks, do not save the files using the DXF file version with less than AC1006.

How to confirm the DXF file version

As the DXF file is the Text file, you can open the file using the editor.
The type of version is mentioned at the beginning of the file.

All the problems come form inaccurate drawing

DXF data for high frequency circuit and as well as for board making machine have to be
in the closed-loop shapes. When you look at the print-out result of the drawing of DXF
date processed by the AutoCAD, it may look free of any problems. But when the magnified
drawing is closely examined, you can detect various defects such as incompletely
closed loop in which the start and finishing points are not neatly joined.

Drawing errors and their correction

We are going to introduce the several types of drawing errors and how to correct them.

Incomplete closing of the segment (line) Before correction   After correction When the segment extension makes an intersection extension of the segment · When the errors is within the tolerable range Before correction   After correction When the segment extension makes an intersection supplement of the segment When the errors is beyond the tolerable range Incomplete closing of the segment (lines) Before correction   After correction Case 1. When the segment extension does not makes an Intersection supplement of the segment When the errors is beyond the tolerable range Before correction   After correction Case 2. When the segment extension does not makes an Intersection supplement of the segment When the errors is beyond the tolerable range Before correction   After correction Case 3. When the segment extension does not makes an Intersection Connect the both ends of lines When the errors is within the tolerable range Various cases of incomplete closing Before correction   Samples after correction Other than the correction examples on the right, there are various corrective methods. As to the best ways for the correction, let us ask for an advice from the drawing designer.   Overlapping (Redundant segment or line) Redundant segment or line Crossing Before correction   After correction Case 1. When the two lines are crossing each other Deletion of the unnecessary lines When the errors is within the tolerable range Overlapping of loops Before correction   After correction When the closed loops touch each other     Overlapping (The two loops ) Before correction   After correction When the two loops are overlapping Before correction   After correction When the area where the two closed loops with openings are overlapping each other.

Correction of DXF data for high frequency circuit simulator

At the time of simulating operation, you can modify the importing DXF data into the electromagnetism
simulator in the following manners, so that you can shorten the simulation time only with minimum
level of accuracy deterioration.

Minimization of minute-distance lines When using the data which are the composite of the splines (such as oval or Bezier curves), the number of such composite is consisted of several hundred pieces (number of meshes). Compartmentalization * Reshaping of circles or arcs into polygon shapes Before correction (with lots of meshes)   After correction (with less meshes) Correction of any portion where the segments or lines of a few-micron size are leftover

At the closing

As the DFX data look like as if the data are drawn on the print-out papers by the designer,
it is important for you not to conclude that they are error-free. Therefore, it is your responsibility
to draw your circuit data very accurately in appropriate manners.
We do hope that what we have explained here in this website for your proper handling of
DXF data can enable you to lighten the time-consuming burden for your successful board
making operation.

* We are now preparing the conveniently compiled DXF correction/modification programs
together with other useful programs. The new programs will be made available for sales
within the year 2007.