An UWB 3-D Rolled-Up Delay Line for Phased Array Systems in the 5G Sub-6 GHz Frequency Band

To reduce the area occupied by delay lines for the 5G sub-6-GHz frequency band, a 3-D rolled-up structure is presented in this letter. According to the rules proposed in this letter, a conventional planar interdigital delay line is rolled up, transforming the initially planar device into a 3-D spiral geometry. When rolling the device into 1 turn, the area occupied by the rolled-up interdigital delay line is reduced by over 65% while maintaining similar performance to the unrolled device. From 1 to 6 GHz, the return loss of the input and outputs port is greater than 13.1 dB, and the insertion loss is less than 3 dB. The group delay is 1.8 ns±5% over the operating band.