Abstract: Owing to the dispersive characteristics, the leaky wave antenna can have its beam direction scanned with frequency. This property can be utilized in a frequency scanning system. However, in a narrow-band system or a system that does not support frequency scanning, the frequency scanning capability cannot be effectively utilized. In this paper, three implementation methods for fixed frequency beam reconfigurable leaky wave antennas are introduced: tuning the phase constant of the fundamental space harmonic for uniform/quasi-uniform leaky wave antennas, tuning the phase constant of the radiating higher-order space harmonic for periodic leaky wave antennas, and switching different space harmonics for radiation. Based on the three methods, three fixed-frequency beam-steering antennas with different structures are designed: a fixed-frequency beam steerable quasi-uniform microstrip leaky-wave antenna loaded with microstrip stubs, a periodic leaky wave antenna which regulates the higher-order radiating space harmonic by adjusting the period structure with PIN diodes, and an endfire/backfire reconfigurable leaky wave antenna by switching different spatial harmonics for radiation. Analysis and measurement results demonstrate that these leaky wave antennas can realize beam steering at a fixed operating frequency, and exhibit favorable radiation performance.