Researches On Miniaturized Multi-Mode Broadband Base Station Antennas

With the rapid development of mobile communication system,the Ministry of Industry and Information Technology confirmed multiple communication bands in China to meet the requirement of high quality and large communication capacity.To save the space and resources,broadband miniaturization multi-mode coexist base station antenna is an inevitable trend.As an important part of communication system,base station antenna will become more and more important.In order to achieve the miniaturization of RF front end,the antenna with integrated filtering characteristics has important practical significance and application value.The main innovative work of this researches are as follows:???A design method of wideband miniaturized base station antenna is presented in this paper.Based on the loop cross dipole,the two-mode resonant characteristics of the antenna are deeply studied.We find that the non-uniform coupling is introduced with chamfer.On the one hand,the effective current path of the dipole can be changed so that the low-frequency resonant mode moves toward the lower frequency.On the other hand,the coupling between the dipole and the coupled resonant loop can be changed,so that the high-frequency resonant mode moves toward the higher frequency.In addition,two antennas are designed to verify the flexibility and effectiveness of the design method of wideband and miniaturized antennas by introducing non-uniform coupling.All antennas have the characteristics of miniaturization,wideband,stable radiation patterns and gain.???Based on the half-wave dipole,the design method of wideband antenna based on the concept of multi-mode filter is proposed.A new resonant mode can be introduced for the coupling between the dipole and resonator.And the resonant mode is controllable with the size of the resonator and the coupling distance between the resonator and the dipole,which greatly increases the bandwidth.The LTE700/GSM850/GSM900 band single-polarized and dual-polarized antennas are designed by using the resonator coupling method.Wide impedance bandwidth,stable radiation patterns bandwidth and gain bandwidth are achieved.A prototype of a five-element antenna array is designed.The measured and simulated results are in good agreement with each other,which are suitable for modern mobile communication systems.???A new approach to realize the design of broadband multi-array antenna by reducing the mutual coupling and using the mutual coupling is proposed.The design method of miniaturized antenna with terminal loading and step gradient structure are studied,and a miniaturized 1710-2690 MHz high-frequency and 698-960 MHz low-frequency antenna element is proposed.Based on the miniaturized antenna element,a multi-array wideband base station antenna is proposed.The antenna is composed of two low-frequency and five high-frequency elements.A compact coaxial structure is formed by nested arrangement of higher and lower band element.The measured results show that the antenna covers the 698-960 MHz and1710-2690 MHz bands with stable half-power beamwidth,gain and high cross-polarization discrimination.???Two main problems brought by low-profile antenna and corresponding solutions are studied.A broadband low-profile±45°dual-polarized base station antenna element with traditional conductor reflector is proposed.Based on the low-profile antenna element,a five-element antenna array is designed for the LTE700/GSM850/GSM900 band.Low-profile of0.164?₀??₀ is the wavelength corresponding to the center frequency of the operating band?is achieved.???Based on the requirement of 5G communication system in the future,the design method of multi-mode wideband antenna based on stub-loaded and resonator coupling is studied.A wideband dual-polarization antenna covering 1710-3600 MHz is realized by loading a resonant stub inside the loop dipole.A broadband dual-polarization base station antenna covering 550-960 MHz is implemented without changing the height of the antenna profile by introducing a coupling resonator under the dipole.Stable gain and radiation patternas are achieved.???A dual-polarized base station antenna with integrated filtering function is proposed.It is found that a radiation null can be introduced by adding a rectangular ring slot to the parasitic patch,and the radiation null point is controllable with the size of the slot.By introducing two gaps of different sizes,one radiation null is induced on each side of the left and right sides of the passband respectively,a good out-of-band suppression characteristic and frequency selectivity are obtained,and the integrated fusion design of filter and antenna is realized.The proposed dual-polarized filtering antenna has only a simple two-layer structure and stable gain and radiation patterns.