The Antenna Bars emoji is the signal bar you see at the top of a smartphone status screen. They are there to let you know if you have signal from your service provider to make calls or send texts.
The antenna bars emoji was introduced in 2010 and released as part of the Unicode 11.0 standard. This emoji can be found under the symbols
category. Because the antenna bars emoji has been around for quite some time, it should display correctly in the majority of operating systems.