Broadband SIW Sequential Feeding Network

In this paper, a broadband and low-loss sequential feeding network is proposed and developed on the basis of substrate integrated waveguide (SIW). Phase shift is not only generated by adding delay line but also using unequal-width SIW, which can make the feeding network operate over a broadband. The amplitude imbalance is within 0.7 dB while the phase error is less than 10° over the frequency band from 16.9 to 23.6 GHz or 33.4% relative bandwidth. Measured and simulated results of the proposed structure are in a good agreement. This sequential feeding network has wide band and low insertion loss, so it is attractive to be used in the design of broadband SIW circularly polarized antenna arrays.