I had problems with the Wi-Fi for some time reach of an ESP8266-01.
Therefore, I have searched for a solution and found this antenna:
You get two antennas and two cables for the money.
Then I broke the trace of the original antenna in these two places.
Then soldered to the head of the new antenna to the rest of the trace and solder the shield to the old antenna.
Now I have a much better Wi-Fi coverage and a better grid stability as before.
Possibly, the shielding of the new antenna with GND should be connected. But it works for me so great.
A soldering station and a good magnification is an advantage for this work.