Microwave / Millimeter-wave Delay Line

Time delay line is an important device in microwave technology, it produces a constant time delay when electromagnetic wave propagates between two ports, and it has become an indispensable electronic component in the signal processing, radar, anti-electronic and phased arrays etc. As a new kind of transmission line, Substrate Integrated Waveguide (SIW) which borrows advantages of low loss ,easy to be processed and integrated with other circuits, is now be widely used in microwave circuits. Electromagnetic Bandgap (EBG) structure is a kind of periodic structure which has some special characteristics, such as slow wave, bandstop and high effective characteristic impedance. EBG structures have been widely used in the design of microwave circuits.After analyzing the characteristics of SIW and EBG, a novel SIW time delay line is proposed in this paper to achieve true time delay. The delay line is formed by loading the SIW with EBG, which can achieve high delay efficiency by adjusting structure size. As examples, K-band and Ka-band delay lines have been designed.A delay line with group delay of 0.11 ns in K-band has been designed and mesured, the band-pass frequency range is from 17.5GHz to 24.5GHz.1λ_g,2λ_g,4λ_g,8λ_g delay lines have been designed and mesured, the band-pass frequency range is from 27.7G GHz to 37.7GHz. The simulation results and measurement results show good consistency.