Spoof surface plasmonic circuit supporting both odd-mode and even-mode transmissions

In microwave communications, circuits supporting both odd-mode and even-mode transmissions have stronger anti-interference ability than single-ended circuits, enabling high signal transmission efficiency. Here, a spoof surface plasmonic circuit is proposed and measured, which supports both odd-mode and even-mode transmissions. This circuit is composed of a feeding structure connected with a cross-shaped spoof surface plasmon polariton transmission line to guide multi-mode waves. The odd and even modes can be generated by simply switching the input port without changing the circuit layout. A transition structure connecting the feeding line and the SSPP transmission line is designed to meet the requirements of mode conversion and impedance matching. Our simple design improves the flexibility and efficiency of the multi-mode transmission circuits, and may find applications in modern communication systems.