A novel technique to eliminate the open stopband in one-dimensional periodic printed leaky-wave antennas

In this paper we deal with the problem of the Open StopBand (OSB) in one-dimensional (1-D) periodic printed Leaky- Wave Antennas (LWAs). In particular, a LWA realized periodically loading a microstrip line with two open-ended stubs per unit cell is considered. The dispersion behaviour of this antenna is analyzed in order to show that a mitigation of the open-stopband effects can be achieved. Moreover, an optimization of its performances near broadside is discussed through a transmission line analysis, changing the distance between the two radiating stubs. Finally, a novel technique to completely eliminate the open stopband is presented. Numerical results for the dispersion behaviour and for the antenna gain are reported to validate both the optimization and the elimination of the OSB.