Broadside radiation in frequency-scanning periodic leaky-wave antennas : circuit analysis, asymptotic formulas, and fundamental behaviors

In: IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting Registration, Short Courses and Workshops
paper no. TH-AMa.13.2, Spokane, WA, USA (2011), pp. 223-225
Buchaufsatz / Kapitel / Fach: Elektrotechnik
Fakultät für Ingenieurwissenschaften
Frequency-scanning periodic leaky-wave antennas are prone to gain degradation when scanned through the broadside direction (Paulotto, S.; Baccarelli, P.; Frezza,F. & Jackson, D. (2008), 'Full-Wave Modal Dispersion Analysis and Broadside Optimization for a Class of Microstrip CRLH Leaky-Wave Antennas', IEEE J MTT 56(12), 2826{2837.). Our contribution addresses this phenomenon using a simplified
transmission line (TL) analysis and points out the required conditions to mitigate this issue. The radiation power and dissipation loss of an antenna unit cell can be decomposed into series and shunt contributions in the equivalent TL network model. We identify two regimes, the "broadside" and "off-broadside" regimes, for which we present asymptotic formulas for the propagation constant, quality factor, Bloch impedance, stored energy and dissipated power.