`--export-field` 不生成任何 .h5 文件 (Ubuntu 22.04, openEMS commit a305877)

[Camille-cjl]

环境：

• OS: Ubuntu 22.04 (VMware)
• Python: 3.11
• openEMS: commit a305877, 编译至 ~/opt/openEMS
• gerber2ems: 最新版

复现命令：
gerber2ems -a --export-field outer cu-outer cu-inner substrate -d

现象：
仿真完成，S参数/史密斯图正常生成，但 ems/ 目录下无 .h5 或 fields 文件夹。geometry.xml 中存在 DumpBox，但求解器未写入数据。

附件：

• 完整终端输出：

terminal_output.txt

• geometry.xml 内容（关键部分）：

geometry.xml
geometry_DumpBox.txt

• ls -la ems/ 输出：没有 fields 文件夹或 .h5 文件
  cjl@cjl-virtual-machine:~/gerber2ems/examples/stub_short$ ls -la ems/
  总计 20
  drwxrwxr-x 5 cjl cjl 4096 5月 8 09:30 .
  drwxrwxr-x 4 cjl cjl 4096 5月 8 09:29 ..
  drwxrwxr-x 2 cjl cjl 4096 5月 8 09:29 geometry
  drwxrwxr-x 2 cjl cjl 4096 5月 8 09:30 results
  drwxrwxr-x 3 cjl cjl 4096 5月 8 09:30 simulation

[Camille-cjl]

hi，--export-field does not generate any .h5 file (Ubuntu 22.04, openEMS commit a305877)
Environment:
OS: Ubuntu 22.04 (VMware)
Python: 3.11
openEMS: commit a305877, compiled to ~/opt/openEMS
gerber2ems: latest version

Steps to reproduce:
gerber2ems -a --export-field outer cu-outer cu-inner substrate -d

Observed behavior:
Simulation completes successfully, S-parameters and Smith charts are generated normally, but no .h5 files or fields/ folder appear inside the ems/ directory. geometry.xml contains DumpBox entries, but the solver does not write any field data.