| With the continuous increase of the working frequency band of the communication system,multi-band antennas that can only work in the microwave band will be difficult to meet the needs of future high-speed microwave and millimeter-wave wireless communication.Most of the existing multi-band antennas can only work in the microwave or millimeter-wave band.Therefore,the study of multi-band antennas with large frequency ratio that can work in the microwave and millimeter-wave bands have important practical application value for future communication applications.In this paper,several multi-band antennas with large frequency ratio are designed based on the microstrip and substrate integrated waveguide technology.The main work is as follows:1.By designing microwave and millimeter wave antennas separately,and then combining the two antennas horizontally to realize high frequency ratio,we designed two quad-band antennas with large frequency ratio.One of them is a four-band microstrip antenna with high frequency ratio that works in 2.4GHz,5.2GHz,11.8GHz and 60 GHz frequency bands.The antenna consists of a microstrip grid array antenna working in the 11.8GHz and 60 GHz frequency bands and an inverted F antenna working in the 2.4GHz and 5.2GHz frequency bands,both of which are fed by coaxial feeding.The other is a four-frequency slot antenna with large frequency ratio that works in the 2.7GHz,5.3GHz,8GHz and 60 GHz bands.The antenna consists of a microstrip grid array antenna working in the 8GHz and 60 GHz and a slot antennas working in 2.7 GHz and 5.3GHz.The grid antenna is fed by coaxial feeding,and the slot antenna is fed by microstrip.2.By means of functional multiplexing and structural multiplexing to improve the performance of the large frequency ratio antenna and reduce the size of the antenna,we have designed two SIW-based cavity-backed antennas with large frequency ratio.One of them is a SIW-based cavity-backed antenna with a large frequency ratio that operates in the 3.3GHz,5.2GHz and 33 GHz bands.The antenna consists of a SIW back cavity slot antenna working in the 33 GHz band and two patch and semicircular SIW cavity hybrid antennas working in the 3.3GHz and 5.2 GHz bands respectively.The SIW back cavity slot antenna is fed by coaxial,while the two hybrid antennas use 50? coplanar waveguide(GCPW)as the feeding element,and a 50 ohm microstrip line is connected to the end.Through further improvement,the SIW slot back cavity antenna and the two hybrid antennas share one patch to radiate,thereby obtaining another SIW-based large-frequency ratio tri-band antenna.3.By means of structural multiplexing to improve the performance of the large frequency ratio antenna and reduce the size of the antenna,a hybrid antenna with large frequency ratio working in 3.4GHz and 26 GHz frequency band was designed.The antenna consists of a grid antenna operating in the 26 GHz frequency band and a hybrid antenna operating at 3.4 GHz.In the millimeter wave frequency band,the grid antenna is fed by coaxial feeding,so that the grid antenna works independently.In the microwave frequency band,the coupling effects is used to excite the TM010 mode of the grid patch with a semi-circular cavity,thereby increasing the bandwidth and gain of the hybrid antenna. |
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