Dual Polarized Frequency Swept Antenna

With the continuous development and application of radar,communication,and mobile TV technologies,electrical scanning antennas have been widely used in various fields and have been rapidly developed.In the commonly used electric scanning antenna technology,the change of the lobe direction is realized by changing the working frequency of the antenna,that is,a frequency scanning antenna is formed.The dual-polarized microstrip antenna not only has the advantages of small size,light weight,and easy conformal,but also can simultaneously emit two orthogonal polarized electromagnetic waves that do not interfere with each other,carrying double the amount of information.This article describes the basic theory of frequency-swept antennas and dual-polarized antennas,and studies dual-polarized frequency-swept antennas.First,the research background and research status of frequency-swept antenna and dual-polarized antenna are introduced.Next,the basic working principle of the frequency-swept antenna is introduced,and its basic structural parameters and calculation formulas are explained in detail.After that,the calculation method of the coupling coefficient of each element of the cross-fed swept antenna array is given and a specific example is given.Finally,this paper proposes the application of two dual-polarized antennas in frequency-swept antennas.First,in order to achieve a high-frequency-sensitivity frequency-swept antenna,the two frequency-scanning subarrays are controlled to work separately through the RF switch,and the above two subarrays have the same operating frequency but correspond to different beam scanning ranges,so as to achieve high frequency sensitivity.According to the principle of the microstrip antenna size calculation and the initial data of the dual-polarized antenna,the parasitic patch is added to widen the bandwidth.The main size parameters of the antenna are studied,and the parameters of the antenna resonance characteristics and the influence curve of input impedance.Simulation can get good impedance bandwidth and port isolation.On the basis of the dual-polarized antenna unit,a low-loss microstrip line slow wave line and a feed coupling structure are designed to form a frequency-swept antenna array.Finally,a 10-element frequency-swept antenna array was processed and tested,and the measured results were roughly consistent with the electromagnetic simulation results.This solution not only improves frequency sensitivity,but also has the advantage of light weight.Second,because the scanning direction of the antenna is a function of the antenna operating frequency,when the enemy breaks this rule,it will cause interference to the mode.In order to improve the anti-interference ability,the two sub-arrays are switched through the RF switch.Working in different frequency bands to achieve frequency switching of frequency sweep antennas.In order to make the two sub-arrays meet the requirements of the array antenna,the working frequency ratio of the two sub-arrays and the distance between adjacent antennas are theoretically analyzed.Based on the dual-band dual-polarized antenna unit,the dual-band dual-polarized frequency sweep antenna scheme was simulated and verified,and two dual-band dual-polarized frequency sweeps were designed based on theoretical analysis.Antenna,simulation proves that these two structures can achieve frequency switching.