Design Of Digital TV Transmitting Antenna Based On Microstrip Structure

The traditional TV transmitting antenna has the characteristics of large volume,complex processing,difficult to debug and high cost.Therefore,it is of great value to study the new TV transmitting antenna with small volume,low cost and easy to debug.Because the transmitting power is large in the broadcasting TV transmitting system,and a little reflection will cause damage to the transmitter.General requirements for return loss is greater than 20 dB(c class)in the broadcasting TV transmitting system.However,the general requirements of the return loss is more than 10 dB in the mobile communication system.Therefore,the requirements of the matching technology in TV transmitting system are more stringent than in the mobile communication system,which is the biggest difficulty in the design.The main works of this paper as follow:(1)A stacked microstrip patch antenna based on the E-shaped patch is proposed,which is with a working frequency of 600 MHz,and reduces the size of the traditional TV transmitting antenna.In order to verify the validity of the method,the antenna is processed and tested.The test results show that the relative impedance bandwidth of the antenna with a return loss of more than 23 dB is achieved to 18.2%(frequency range of 544 MHz?653 MHz).The antenna gain is about 9.23 dBi at the center frequency.(2)In order to obtain a higher antenna gain,a stacked microstrip antenna array with working frequency of 700MHz is designed and fabricated.The characteristics of antenna array at center frequency and edge frequency are measured.The measured results are in agreement with simulation results,which verifies the validity of the antenna array.In the frequency range of 625.1 MHz?775.0 MHz,the return loss is greater than 20 dB,and the maximum gain is about 12.05 dBi.(3)According to the theory and formula of the microstrip line power capacity,the average power capacity and the peak power capacity of the antenna are calculated theoretically.In actual measurement,the antenna can work continuously for twenty-four hours without any abnormalities under the 1kW input power.The results show that the design of the digital TV transmitting antenna based on microstrip structure can be applied to the TV transmission system.