An Improved 3D Ultra-Wideband High-Efficiency Substrate Integrated Coaxial Meander Delay Line

Abstract

This paper proposes an improved substrate integrated coaxial meander delay line to overcome the beam dispersion problem in a spaceborne synthetic aperture radar phased array antenna system with large bandwidth. The delay line operates in the range of 4 GHz–10 GHz with a relative bandwidth of 85.7%. In the proposed structure, the delay effect is generated by the combination of a meander delay line and a substrate integrated coaxial line, which results in a significant improvement in the delay efficiency. Furthermore, a planar turn structure, a vertical transition structure, and a microstrip transition structure are designed to realize three-dimensional tight wiring. The proposed delay lines are fabricated on three and five layered Rogers RO3006 PCB substrate. The experimental tests are conducted on the 3.1 ns and 6.4 ns delay lines with the dimensions of 38 mm × 7 mm × 0.5 mm and 37 mm × 9.2 mm × 1 mm, respectively. The experimental results indicate that the insertion and return losses of the two lines are within the reasonable range. Compared with the related research, the proposed delay lines’ delay time, delay multiplier, and relative bandwidth are improved by 2.13–160 times, 1.025–6.8 times, and 2.14–3.86 times, respectively, which shows their good practical value and application prospect.