A tour on recent developments and discoveries of crucial practical importance in leaky-wave antennas

The paper presents an overview of recent developments and discoveries of practical importance in the area of periodic leaky-wave antennas (LWAs): 1) various innovations in composite right/left-handed (CRLH) LWA structures and systems, 2) the resolution of the issue of poor broadside radiation, 3) the fundamental importance of the symmetry or asymmetry of the unit cell on the properties of the LWA. It concludes by pointing out a fundamental link between all periodic LWAs.