Design Of Coaxial Collinear Broadcast Television Transmitting Antenna

TWireless broadcasting,widely used in urban,rural,and maritime environments,including audio and video radio broadcasting,is implemented by wireless transmission.Since China introduced the "Development Plan for Terrestrial Digital Television Broadcasting Network" in 2012,the promotion and application of digital broadcasting and television has been promoted to a strategic level.Radio and TV transmitting antenna,as an important part of terrestrial wireless transmission equipment,directly affects the quality of TV broadcast signals.Coaxial Collinear(COCO)broadcast TV transmitting antenna has many advantages such as omnidirectional,high gain,wide-band,strong anti-jamming ability,saving space resources and wide coverage.Therefore,COCO broadcast TV transmitting antenna has important value.The research topic of the thesis comes from the antenna simulation design project proposed by Liaoning Putian Digital Co.,Ltd.The project requires simulation design of the broadcast TV transmitting antenna in the UHF band and the L-band digital audio multimedia broadcasting service transmitting antenna.The main work of this paper are as follows:(1)A COCO TV transmit antenna was designed.The antenna adopts a structure in which 11 inner and outer conductors of the coaxial line are staggered and connected,and Each unit is approximately half a working wavelength in length,and the PTFE and air is mixed fill.The simulation results show that the antenna gain is 9.2dBi at the center frequency of 800MHz,the non-roundness within±0.5dB.The standing wave ratio is less than 1.5 at 789-812MHz.The results meet the industry standards.(2)A parallel-connected monopole coaxial TV transmitting antenna is proposed,which is composed of a parallel feeding network and four monopole groups.Each monopole of the array consists of a monopole "ground",an active vibrator,and two parasitic oscillators.The simulation results show that the center frequency is 725MHz,the highest gain is greater than 8dBi,the out-of-roundness is within±.5dB,the standing wave ratio is less than 1.5 in the frequency range of 680-905MHz,the bandwidth is 225MHz,and the internal antenna gain exceeds 7dBi.The antenna achieved the goal of omnidirectional,wideband,and high gain,and completed the project requirements proposed by the company.(3)A novel coaxial audio-sending micro-band digital audio broadcasting(DAB)TV transmitting antenna with a center frequency of 1.468GHz is proposed.There are 7 radiator pieces on the front and back of the antenna,and each radiation patch is composed of a gradient trapezoid and a rectangle(referred to as a gradual semi-trapezoidal structure).The radiating patches on the front and back of the antenna are staggered.A radiation patch with a length of half an operating wavelength and staggered ensures that the current flows in the same direction,which causes the electric fields to overlap in the far field region,so that the gain is superimposed in the far field region.The simulation results show that the antenna gain reaches 8.3dBi,the non-roundness is withinn±0.5dB,and the standing wave ratio is less than 1.5 in the 1.454-1.488GHz band,the horizontal plane is omnidirectional radiation.The antenna is physically produced.The measured results show that the antenna gain reaches 7.1dBi,the non-roundness is within±0.5dB.The standing wave ratio is less than 1.5 in the 1.455?1.487GHz band.The result meets the requirements of the broadcasting and television industry standard "Technical Specifications of TV and FM Broadcast Transmitting Antenna Feeder System"...