Mode switching for printed antenna structures

Two examples of reconfigurable leaky wave antennas made of printed transmission structures with electronic devices will be reviewed from the mode switching point of view. The first example is switching between a microstrip patch antenna and a leaky wave antenna made of a higher order microstrip line mode. Another example is a leaky wave antenna made of the composite right/left hand (CRLH) metamaterial configurations. By way of bias control of varactor diodes in each unit cell of the antenna, the dispersion characteristics are varied for beam shape and gain control.