# General File Format

A common data structure exists for the .efe, .hfe, .ffe, .ol, .os, .tr and .epl files, which should be understood to use or post-process these files externally.

The general structure of the file formats consists of the following:
The header block contains general information of the entire file. It includes information such as the file type, file format, the source file and when the file was written. Only one header block may be created and must be located at the top of the file. Header lines are denoted by two hash symbols ##, followed by the key/value pairs allowed by each file type for the header block sections. The delimiter used between a key and value is a “:”. Header lines consists of multiple lines of the form:
##<key>: <value>
Comments may be placed anywhere in the file. They are denoted by two asterisks ** in the form:
** <comment_string>
indicating that the rest of that line is to be ignored.
• Solution Block

Any number of solution blocks (typically one per request per frequency) can follow. A solution block consists of the following:

This section contains information that describes the data block and includes information such as the frequency, coordinate system, the request name and column headers. Solution block headers are denoted by a single hash symbol #, followed by the key/value pairs allowed by each file type for the solution block header sections. The format is then #Key: Value for each solution header block line.

• Data Block

The data block contains space delimited values. Values are given in scientific notation (for example, 1.23E-001).

The column headers are part of the solution block header and must be in the following format:
#no of header lines: M
#"Column 1: Line 1" "Column 2: Line 1" ... "Column N: Line 1"
#"Column 1: Line 2" "Column 2: Line 2" ... "Column N: Line 2"
...
#"Column 1: Line M" "Column 2: Line M" ... "Column N: Line M"

Column headers differ from other solution block header lines in that they do not have a key/value pair format. Column header lines also start with a single hash #, but is then followed by the column titles surrounded in quotation marks.

## Units

The following units are used:
• All dimensions are measured in metres (“m”).
• All angles/phases are measured in degrees (“deg”).
• Far Fields
• E-Fields are measured in “V”.
• Gain / Directivity is measured in “dBi”.
• RCS is measured in decibel square metres (“dBsm”).
• For Triangle Currents / Charges
• Surface Current Densities (Electric) are measured in Ampere per metre (“A/m)”.
• Surface Current Densities (Magnetic) are measured in Volt per metre (“V/m”).
• Surface Charges are measured in Coulomb per square metre (“C/m^2”).
• For Segment Currents / Charges
• Wire Currents are measured in Ampere (“A”).
• Wire Charges are measured in Coulomb per metre (“C/m”).
• Near Fields
• E-Fields are measured in “V/m”.
• H-Fields are measured in “A/m”.