Wideband Compact Slotline-to-Spoof-Surface Plasmon-Polaritons Transition for Millimeter Waves

A novel wideband transition between the slotline and the spoof surface plasmon polaritons (SSPPs) is presented in Ka-band. By applying the combination of a short section of the tapered slotline that has an inclination angle with the SSPPs and an additional trapezoid-shaped metallic ground plane, a bandwidth of 60.5% for |S
₁₁
| <; -10 dB is obtained. A fabricated back-to-back prototype verifies that the insertion loss of a single transition is better than 1 dB over the entire operating band. Because of the compact and simple configuration, low fabrication costs, and good operating features, the proposed transition structure is attractive for the design of millimeter-wave antennas and devices.