Leaky-Wave Antenna Array With a Power-Recycling Feeding Network for Radiation Efficiency Improvement

A novel kind of leaky-wave antenna (LWA) array with a power-recycling feeding network is proposed for radiation efficiency improvement. The antenna array is constructed by two kinds of substrate-integrated waveguide LWAs with different periodic slots. One kind of the LWA is designed to work on the fundamental (m = 0) wave and radiates in the forward direction. The other one is designed to work on the -1th (m = -1) spatial harmonic and radiates in the backward direction. The nonradiated power at the end of one kind of the LWA is directly fed into the other (adjacent) kind of the LWA in reverse direction. Therefore, the reversed feeding can compensate the opposite radiation direction of the two kinds of LWAs, and result in a superposition of radiation. So, both the gain and radiation efficiency of the antenna can be significantly improved, while the array maintains a compact size as those of traditional planar arrays. Simulation results are compared with measurement results to validate the proposed concept of integrating different leaky-wave structures into one array.