Research On Filter Antenna And Multi-frequency Common-aperture Antenna

In order to improve the isolation between antennas of different frequency bands,it is necessary to cascade filters to the antennas,but this method will increase the cost and it is difficult to integrate into the compact multi frequency antenna array.At the same time,in order to meet the current communication needs,antennas are gradually developing in terms of multipolarization,multi-frequency bands,light weight and compact structure.However,the compact structure and multiple frequency bands will bring problems such as isolation and stability of radiation performance.In order to solve the problem mentioned above,this paper studies the integrated miniature antenna as well as multi-frequency common-aperture antenna and designs three antennas.They are a bandpass dual-polarization filter patch base station antenna with a high roll-off speed,a dual-frequency dual-polarization common-aperture base station antenna based on a filter antenna,and a triple-frequency dual-polarization common-aperture base station antenna.The specific content is as follows:(1)A bandpass dual-polarization filter patch base station antenna with a high roll-off speed.This paper proposes a filter antenna that works in the 5G frequency band(3.3-4.2GHz),which introduces gain zeros on both sides of the passband by parasitizing a variety of metal parasites above the driver patch.The first parasitic patch controls the low-frequency gain zero point,and the metal square ring and the second parasitic patch control the high-frequency zero point.After processing and testing the model,it shows that the low-band out-of-band gain of the antenna drops from 8.5dBi at 3.3 GHz to-10 dBi at 3.1GHz,and the out-of-band gain at high frequency drops rapidly from 8.5dBi at 4.2 GHz to-11 dBi at 4.4 GHz.Besides,the in-band loss is relatively small and the polarization gain is above 8dBi.(2)A dual-frequency dual-polarization common-aperture base station antenna based on a filter antenna.This paper presents a compact dual-frequency dual-polarization commonaperture base station antenna based on a filter antenna.The antenna's working frequency bands are 690-803 MHz and 824-960 MHz.The low-pass filter patch antenna uses parasitic patches and parasitic rings to suppress high-frequency radiation,while the high-pass bowl-shaped dipole antenna suppresses low-frequency radiation through the filter stub on the feed network.The simulation found that when the two are nested together,the inter-frequency isolation exceeds 25 dB,and the radiation performance of the two frequency bands is very stable.(3)A triple-frequency dual-polarization common-aperture base station antenna.On the basis of dual low-frequency common-aperture antennas,the dual low frequency vibrator is firstly subjected to high frequency harmonic suppression,and then the designed miniaturized high frequency vibrator is placed in the dual low frequency antenna.By reasonable layout design,the design of broadband three-frequency common-aperture vibrator is realized,which has a high degree of miniaturization.After processing and testing the model,we can learn that the bandwidth of the antenna covers 690-803 MHz & 824-960 MHz & 1700-2700 MHz,the isolation between high frequency and dual wavelength exceeds 28 dB,and the radiation performance of the three bands is very stable.