One-Dimensional Triple Periodic Dual-Beam Microstrip Leaky-Wave Antenna

In this letter, a novel dual-beam microstrip leaky-wave antenna based on one-dimensional triple periodic (TP) structure is proposed. Through theoretical dispersion relation analysis, it is found that compared to the conventional periodic structure, TP structure has reduced the separation of space harmonics. Hence, more space harmonic modes are brought into the leaky-wave radiation region. Through proper design, m = -1 and m = -2 modes are excited simultaneously. Consequently, the forward and backward propagation waves of these two modes generate two radiation beams in the far-field region. At different frequencies, symmetrical and asymmetrical beam pairs are realized. It provides more flexible and richer beam combinations to support dual-beam applications. Through practical implementations, the measured results show very good agreements with the theory. This new design has the single feeding port to avoid the complicated feeding network.