Design Of Novel Low Cost High Gain Reflectarray Antenna

The reflectarray antenna makes up for the shortcomings of the parabolic antenna and the microstrip array antenna.Compared with the parabolic antenna,its shape is flat,the overall structure is simple,the volume is small,and the weight is light.Compared with the microstrip-fed array antenna,the reflectarray antenna adopts spatial feeding,no complicated feeding network is needed,and the loss caused by the feeding network is reduced,and it is convenient to realize the large-aperture array antenna.In order to reduce the reflection loss,most of the reflectarray antennas are made with expensive special microwave substrates.When a large-scale high-gain array is realized,the cost is extremely high,which limits its practical application.Therefore,how to reduce antenna cost under the premise of ensuring performance has positive practical significance.The main contents of this thesis are as follows:1.Two types of units using FR4 dielectric substrate and air substrate were simulated respectively,and the comparison of the results shows that the reflection loss of the unit mainly comes from the dielectric substrate.In order to reduce the dielectric loss of low-cost FR4 substrates,two types of metallized through-hole loaded patch unit structures are designed.After a series of simulations,it is found that when the upper and lower patches and the through holes form a closed structure,the reflection loss caused by the medium between the patches can be improved.2.The influence of the medium around the patch on the reflection loss of the unit was analyzed,the hollowed-out substrate operation has been implemented for two conventional reflection units.On the premise of ensuring the stability of the unit structure,the unit structure with the lowest reflection loss was designed.Array the two ring units of the hollow medium whose phase shift range reaches 360°.It can be seen from the simulation results that the main beam gain of the double-sided ring array with hollowed-out substrate was increased by about 0.5d B compared with the case without hollowed-out substrate.3.Combining the previous design ideas of "adding metallized through holes" and "hollowing out the substrate",without increasing the cost of the substrate,a new low-cost and high-gain hybrid element array antenna with a working frequency of 13.5GHz is designed,and it is combined with the performance of the array composed of the square patch unit and the array composed of the double ring patch unit was compared.The simulation results showed that when the sidelobe electrical average was lower than-20 d B,the gains of the array composed of the square patch unit and the array composed of the full double ring patch unit are 27.9d B and 27.5d B.The gain of the designed new array antenna has been improved by 0.6d B and 1.0d B respectively.The optimized antenna is processed and measured,and the actual measurement results are basically consistent with the simulation results.