The most common and most likely answer to this crossword clue is the 6 letter word DIPOLE
I've seen this crossword clue in The Daily Telegraph
D
I
P
O
L
E
More clues leading to the result DIPOLE
Buddy explains!

The straight part
We know that "Aerial" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aerial = dipole.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DIPOLE mean?
DIPOLE noun- Any object (such as a magnet, polar molecule or antenna) that is oppositely charged at two points (or poles)
- Any molecule or radical that has delocalised positive and negative charges
- A dipole antenna