| Chirped phaser or delay line,that signals with different frequencies pass through and suffer different time delay,can be used in analog signal processing(ASP).The instantaneous frequency of the output signal will rise or decrease over time.In this thesis,chirped phaser and delay lines based on periodic structures such as Spoof Surface Plasmon Polaritons(SSPP)are studied.The main contents are followed:(1)A reflective chirped phaser based on microstrip SSPP is proposed.This structure is composed of microstrip SSPP transmission line and coupling capacitor according to the synthesis theory and circuit of reflective phaser with arbitrary phase.Compared with the traditional microstrip structure,the physical length of SSPP is reduced by about 31%.The group delay swing is 4ns in the linear bandwidth from 3.31 GHz to 3.36 GHz with slope of 80ns/GHz,which meets the requirements.(2)A cascaded dispersion delay line is proposed.This structure is composed of two sections of transmission lines loaded periodic glide symmetric open stubs with different dimensions to realize the linear group delay.The relationship between the dispersion characteristics and group delay response of unit cell is simulated and analyzed.In addition,effects of input impedance on group delay are studied.Two structures are proposed with slopes of 0.83ns/GHz from 4.4GHz to 5GHz and 2ns/GHz from 4.7GHz to 5.1GHz respectively.The amplitude of S21 is above-4d B and most of S11 is below-10 d B,exhibiting well linear characteristics and transmission performance.The electric length at the central frequency point are 1.26λg and 1.53λg respectively.Measured and simulated results show a well agreement.The structures have the advantages in processing,application and boardband.(3)A dispersion delay line based on periodic open and short stubs is proposed.The dispersion of units and the group delay of the corresponding periodic line are analyzed.Meanwhile,a section of transmission line with periodic short stubs and two sections with periodic open stubs are cascaded to superpose three group delay functions and realize the linear group delay response with wide bandwidth.According to the cascaded input impedance,an impedance converter is loaded at the cascade to decrease the input impedance,which improves the frequency offset of peak group delay.The slope of linear group delay is 0.9ns/GHz from 5GHz to 6GHz.S21 is above-6d B,electrical length is 2.3λg.Measured and simulated results shows a well agreement. |
