An omnidirectional antenna invented by Clarence Beam
An antenna that concentrates signals in one direction✓Правильный ответ
An antenna that focuses the signal into two intense rays
Объяснение
A beam antenna uses multiple elements whose fields add in one direction and largely cancel in others, concentrating the radiated energy into a main lobe. That gives gain in the favoured direction and reduces radiation elsewhere; it is a description of behaviour, not of construction material.