A feat : a mini helicopter flying in Mars extremely thin atmosphere
The Martian atmospheric pressure is - on average - more than 100 times below Earth's. Yet, to fly, a helicopter uses atmosphere density. On Mars, Ingenuity will have to speed up its double rotor to go close to 3000 turns per minute to hope for a take-off. It should work because of its light weight : less than 2 kilos.
To be able to make it, its whole telecommunication subsystem (antenna, radio, cables) had to weigh less than 13 grams, while being strong enough to survive its trip to Mars. As an example, mini-satellites systems (CubeSats) weigh a few kilos.
Nacer Chahat, a senior antenna/microwave engineer with JPL-Caltech/NASA, and a former student (and doctor) at Université de Rennes 1, designed the feather-light antennae supporting the radio link on both Ingenuity and Perseverance. Check out this interview with one of his former teacher in Rennes 1.