Al-Bassam, AmarAmarAl-BassamHeberling, DirkDirkHeberlingCaloz, ChristopheChristopheCaloz2026-02-142026-02-1420239781665442282https://publica.fraunhofer.de/handle/publica/50702810.1109/USNC-URSI52151.2023.102376282-s2.0-85172420852Over the past decade, the issue of gain degradation at broadside in periodic leaky-wave antennas (P-LWAs) has been resolved, using a circuit modeling approach, by introducing proper asymmetry in the unit cell of the antenna structure. This paper provides a more fundamental and insightful perspective of the problem by showing, using a simple coupled-mode analysis, that the optimal level of structural asymmetry corresponds to an exceptional point of the coupling parameter between the two eigenmodes of the P-LWA. This contribution represents a key step towards the development of a full electromagnetic resolution of the broadside issue; the second and final step, which will involve a mapping between the complex temporal and spatial eigenfrequencies, will be also presented at the conference.enfalseconference paper