Short answer: Yes.
Long answer: There are two ways to prevent the radar energy from being reflected back to its source in order to avoid detection:
- Absorption, and
- Directed reflection.
Absorbers work well only over a small wavelength band, so some reflection is unavoidable. Now the idea is to collect all reflected energy along specific directions, so the aircraft will reflect very little energy in all other directions.
Radars can adjust their sensitivity, and if they operate at their most sensitive setting, they will detect many false positives, but also a stealth aircraft. If the stealth aircraft maneuvers, it will momentarily shine one lobe of the reflected radar energy back at the radar receiver, causing it to reduce sensitivity such that the weak returns in all other directions will not be registered. Compare this to a diamond which will reflect light back at specific angles, causing it to sparkle.
There are two-lobe designs (Northrop YF-23 and B-2) and four-lobe designs (Lockheed F-117 and F-22), but the idea is the same in all cases. Reflected radar energy is focused in narrow beams, so very little is given off in all other directions.
This is not to say that such aircraft can evade detection. When the radar stations are networked, they can pretty well trace those sparkles and stitch together the aircraft's location. Also, NATO aircrews which had participated in international maneuvers were less than impressed with the stealth capabilities of their colleagues, but were under a gagging order to be more specific.
And then there is infrared. What does it help to be invisible on radar if the aerodynamic heating of the leading edge can be picked up by an IR receiver from 300 km away? When B-2s were flown over to the Farnborough airshow, British Eurofighters could detect them far out over the Atlantic already.