Substrate integrated waveguide slot array antenna covered by circularly polarised array patches

A novel substrate integrated waveguide (SIW) slot array antenna covered by circularly polarised array patches is proposed. The corner-truncated rectangular patch covering the radiating slot is introduced to generate the circular polarisation. To increase the normalised resonant conductance, the patch is moved from the centre line of the slot. The design procedure is similar to the conventional SIW slot array antenna due to the slot combined with the patch that can be seen as a radiating element. A 4×4 array antenna with uniform distribution is designed, fabricated and measured at the Ka-band. The measured results agree well with the simulations.