How to retrieve array of objects in Elastic Search using PPL (Open Search) query

Question

I have an array of objects inside ElasticSearch in signals field:

    "ChargingStationID": "CS1",
    "timestamp": "2019-06-03T14:51:38.009Z",
    "signals": [
      {
        "signal": "Signal1",
        "value": 286
      },
      {
        "signal": "Signal2",
        "value": 967
      },
      {
        "signal": "Signal3",
        "value": 662
      },
      {
        "signal": "Signal4",
        "value": 830
      },
      {
        "signal": "Signal5",
        "value": 572
      },
      {
        "signal": "Signal6",
        "value": 275
      },
      {
        "signal": "Signal7",
        "value": 278716166893
      },
      {
        "signal": "Signal8",
        "value": 368989185886
      },
      {
        "signal": "Signal9",
        "value": 96
      }
    ]
  }

I tried to get every object inside signals with following PPL (Piped Processing Language) query:

search source=my-index | where ChargingStationID='CS1' | fields signals

when I run PPL query above from Kibana Query Workbench I got only the first object of the signals array.

I don't know if is possible but I am stucking and there are no resources around the web focusing on it.

How can I get all values inside signals using PPL query?