Why is the antenna important?

Antenna is the most physically visible component of a wireless infrastructure. It plays a vital role in the era of wireless technology . Why is the antenna so important ? Briefly speaking, the antenna is a device for transmitting and/or receiving signals -the eyes and ears of your communication systems.
An effective and efficient wireless network will require antenna to operate properly. A good antenna provides a professional solution to wireless connectivity. If the poor antenna is chosen, the wireless network will not work. And there exists many different types of antennas with many different specifications. In many situations the choice of antenna type is based on performance and cost.