High-resolution transmission-type (TT) dispersive delay structure (DDS) based on reflection-type (RT) elements

It is shown that reflection-type (RT) dispersive delay structure (DDS) units are inherently superior to transmission-type (TT) DDS units in terms of analog signal processing resolution, since they provide a higher group delay swing. However, RT-DDS units suffer from the drawback of requiring a circulator to separate the input and output signals. In order to solve this issue, the paper presents a TT-DDS unit formed by combining two identical RT-DDS units through a hybrid coupler. The proposed TT-DDS unit is experimentally demonstrated in a two-unit DDS to provide a resolution enhancement of more than one order of magnitude compared to its purely TT-DDS counterpart.