Microstrip leaky-wave antenna fed by short-end CPW-to-slot transition

Single and dual-beam microstrip leaky-wave antennas fed by a short-end coplanar waveguide (CPW)-to-slot transition are presented. The radiation bands of the antennas are deduced from the leaky-wave propagation characteristics of the microstrip line first higher order leaky mode. The measured reflection coefficients of the radiation band confirm the predicted leaky band and the measured radiation patterns exhibit the frequency-scanning feature of the leaky-wave antenna. The short-end CPW-to-slot transition feeding method simplifies the circuit layout and is more suitable for different band design than the CPW-fed microstrip first higher order leaky-wave antennas presented in the literature