A delay line based on synthesized coplanar waveguide

In this work, a miniaturized, artificial transmission line is proposed as delay line for a frequency scanning array antennas. The delay line comprises 15 cascaded synthetic coplanar waveguide cells and was fabricated with a low cost FR4 substrates. The design was optimized via simulation and its performance was validated with the fabricated prototype delay line. At 2.4 GHz, the 16 cm long line provides a phase delay of 2650 degrees with approximately 4 dB attenuation. The equivalent slow wave factor is around 6. The compact and low loss features of the proposed delay line are helpful in reducing the beam steering bandwidth needed for frequency scanning array antennas.