| As an indispensable key component of the mobile communication system,the base station antenna plays a very important role.With the continuous development of wireless technology,mobile communication base stations need to support multiple different communication standards and different frequencies at the same time,which requires the use of more base station antennas.However,the limited space of the base station site is contradictory to the inherent requirements of the increase in the number of base station antennas,such as the development trend of system miniaturization and compactness and the need for base station antennas to support more and more frequency bands are practical problems that need to be solved,which leads to increasing antenna design difficulties.Therefore,for the specific problems of base station antennas in different applications,such as whether miniaturization can be achieved when covering multiple frequency bands,whether the pattern and gain can be stable,and so on.Starting from traditional dipole antennas and taking advantage of their various forms of convenience,this paper carries out application research on ultra-wideband dual-polarization base station antennas,the main contents of which are as follows:1.Proposed a compact two-polarized ultra-wideband base station antenna based on PRS(Partially reflective surface)technology(1.4-2.8GHz).The antenna is based on dipole,each arm of the dipole is divided into four axisymmetric seven-sided rings,and then Y-shaped and L-shaped parasitic units are introduced around the antenna,and the parasitic unit is excited by coupling feed and gap feeding,so that it can continuously cover three mobile communication frequency bands(1.4-2.8GHz),which greatly expands the bandwidth and ensures the profile of the antenna.In addition,in order to achieve better matching and ensure the stability of the pattern and gain,PRS is introduced directly above the antenna to ensure good in-band matching(|S11|<-14 d B)。 The test results of the processed samples verify the proposed design ideas.2.Based on the previous work,a dual-polarized ultra-wideband base station antenna with a more compact 0.57-1.05 GHz peripheral structure is further proposed.PRS technology is not utilized here by sacrificing matching bandwidth within slightly(|S11 | less than-14 d B becomes less than-10 d B)to ensure that the antenna has a low profile and is compact.A three-stage coupled feed is still used to excite the parasitic unit to achieve ultra-wideband,and the internal dipole and its parasitic unit are conventional squares,and the external irregular square is used to couple to as much current as possible;At the same time,grooves are dug at the corners of the third resonant unit,that is,the outer ring,to increase the capacitance of the corresponding area,so as to ensure the independence of the high frequency resonance point.The test results of the processed samples confirm the proposed design ideas.3.A low-frequency unit(690-960MHz)with wave transmission to high-frequency(1.7-2.1GHz)is proposed to achieve its effect of almost no influence on the radiation of adjacent high-frequency units and even stealth,and solve the distortion problem of high-frequency unit pattern when high-frequency and low-frequency units are of common aperture.By designing a high-frequency current cancellation structure on the low-frequency unit,the high-frequency current coupled from the high-frequency unit on the low-frequency unit is suppressed,and the transmission of the low-frequency unit to the high-frequency unit radiated signal is realized.In this paper,four traditional high-frequency dipole units(1.7-2.1GHz)are formed into a 2×2 array and their pattern is recorded.The low-frequency transmission antenna is then placed in the center of the array and the pattern of the entire antenna is recorded at the same time.Through simulation,it is found that the pattern of the high-frequency unit is basically unchanged in two situations,which verifies the effectiveness of the design. |
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