Design Of Ka-band Differential Phase Shifter Based On Metamaterials

In recent years,the application of phased array radar is gradually developing towards the millimeter wave frequency band,so as to make full use of the rich spectrum resources of the millimeter wave frequency band to improve the performance of the equipment.As one of the important components of the phased array radar system,the phase shifter has gradually increased the requirements for the working frequency band,miniaturization,low loss and reliability of the phase shifter.Due to the diverse structural forms and unique electromagnetic properties of electromagnetic metamaterials,their application research in millimeter-wave phase shifters has gradually attracted widespread attention.In this paper,some millimeter-wave differential phase shifters with low loss,miniaturization,and low phase-shift error working in Ka-band are designed by using the electromagnetic metamaterial structure.In order to achieve the characteristics of miniaturization and low insertion loss of the device,a millimeter-wave differential phase shifter is designed using the composite right/left-handed(CRLH)transmission line structure based on interdigital capacitance and ground inductance.Firstly,a differential phase shifter with a T-shaped structure is designed,which can control the output phase by changing the length of the outermost interdigital capacitor.Secondly,on the basis of the T-shaped structure,the single grounding inductor is changed into two grounding inductor structures symmetrical about the center.By this way,the miniaturization of the phase shifter is realized,and the size is 1mm×0.8mm×0.056 mm.Finally,in order to solve the problem that the above-mentioned phase shifter has a small amount of phase shift.On the basis of the above structure,by optimizing the linear interdigital capacitance to be C-type,a larger phase shift amount is effectively achieved.The final designed differential phase shifter can achieve differential phase shifts of 11.25°,22.5° and 45° respectively in the 29-31 GHz frequency band,and the insertion loss is about 1.3d B,achieving the design goals of miniaturization and low loss.In order to achieve a relatively larger amount of phase shift and smaller phase shift error,a millimeter-wave differential phase shifter is designed using a CRLH transmission line based on a split resonant ring(SRR).Firstly,a differential phase shifter is designed using a single SRR structure.It turns out that changing the radius of the SRR is an effective way to control the output phase.The phase shifter can achieve a maximum differential phase shift of 42.5° in the frequency band of 30-32 GHz.On the basis of the above structure,a differential phase shifter composed of two SRRs and a central ring is designed.The reflection coefficient,insertion loss,phase shift error and other indicators of the phase shifter can be optimized by changing the radius of the center ring.After selecting the appropriate center ring radius,the output phase can be adjusted by changing the radius of the SRRs.In the working frequency band of 30-32 GHz,the designed differential phase shifter can achieve differential phase shifts of 22.5°,45°,and 90°,and the phase shift error is less than 2.1°.The design goals of relatively large phase shift amount and small phase shift error are achieved.Finally,the differential phase shifter sample is packaged and processed,and the test results verify the reliability of the simulation results.The differential phase shifter has the advantages of simple structure and easy manufacture,small phase shift error.And it has certain reference value.