A π-matching network to eliminate the open-stopband in 1-D periodic leaky-wave antennas

In this paper the problem of obtaining efficient broadside radiation in one-dimensional (1-D) periodic printed leaky-wave antennas (LWAs) is addressed. In particular, a technique for the elimination of the open stopband (OSB) is presented, which is based on a π network that matches the Bloch-wave impedance of the structure to a desired (non-zero) value at broadside. Three different matching conditions are investigated. Their advantages and drawbacks are briefly discussed and the effectiveness of the technique is demonstrated on a real structure.