The Periodic Leaky-Wave Antenna With Different Unit Cells Based on Consistent Fundamental Mode

In this article, we present a novel periodic microstrip leaky-wave antenna (MLWA) design based on different unit cells. The proposed antenna consists of three different kinds of unit cells developed in our previous works, in which the wavenumber of fundamental mode is basically consistent. Big period cascaded by the three different unit cells is introduced for producing a relatively narrow radiation beam. Almost same radiation angle of the antenna is obtained regardless of the permutation of unit cells, which provides more design freedom on antenna structure. Slotting and pins loading technique are applied in unit cells for canceling the reactance of the big period, thus a continuous beam scanning with small gain fluctuation around broadside direction could be achieved. The prototype is fabricated and measured, demonstrating the feasibility of this novel periodic antenna design and well agreement between simulated and measured results. Measurement results show the main beam steers continuously from -46° to 31° with the operating frequency changes from 6 to 9 GHz. The peak gain reaches up to 12.8 dBi at the frequency of 7 GHz.