A compact and wideband SMA connector to empty substrate integrated waveguide (ESIW) transition

In this paper, a novel excitation technique by a commercially available SMA connector is presented for the empty substrate integrated waveguide (ESIW). The SMA connector is directly connected to one end of the ESIW. A prototype back-to-back transition is designed and fabricated for X-band operation. Measurement results show that the insertion loss of the back-to-back transition is below 1 dB over 7.15 GHz to 12.5 GHz. Losses from the transition are studied in details. The transition has a compact dimension of 22 mm × 3.5 mm.