2 Radio Frequency: Radio Frequency abbreviation RF radio frequency is radio frequency current, is a high-frequency alternating current changes in electromagnetic waves, for is the abbreviation of Radio Frequency, said can be radiated into the space of the electromagnetic frequency, the frequency range between 300KHz ~ 300GHz. Changes per second less than 1000 times the alternating current known as low-frequency current, greater than 10,000 times known as high-frequency current, and radio frequency is such a high-frequency current. High frequency (greater than 10K); RF (300K-300G) is the higher frequency band of high frequency; microwave band (300M-300G) is again the higher frequency band of RF. RF technology is widely used in the field of wireless communications, cable television system is the use of radio frequency transmission.