Open Stopband Suppression of Periodic Leaky-wave Antenna Based on Theory of Small Reflections

A technology based on theory of small reflections for open stopband suppression in the periodic leaky-wave antennas (PLWA) is presented. The open stopband suppression is realized by the superposition and cancellation of multiple reflected waves generated by discontinuities of periodic structures. By modifying the discontinuities, the phase and amplitude of each reflected wave could be modulated separately within a certain frequency band. Choosing the proper phase and amplitude of reflected waves, the total reflected wave could be reduced to a low level, even to zero, and then, the abnormally large reflection in the open stopband is suppressed. Two spoof surface plasmon polaritons (SSPP) based PLWA are developed to verify the technology. The results show that good VSWRs and radiation performances are achieved when the beam scans through broadside direction. This technology could have applications in the design of various types of PLWA, such as microstrip, waveguide, and SSPP PLWAs.