Radars are basically systems that use radio waves to detect objects. They emit radio waves in order to determine whether an object is in the sky.
Beyond visual range air-to-air missiles (BVRAAM) are aerially launched munitions designed to engage targets in excess of 30km.
In a sense, WVRAAMs are perhaps the most ubiquitous aspects of air-to-air warfare. The first widely adopted WVRAAM was the AIM-9 Sidewinder.