LAUSR

A miniaturized and reconfigurable rat-race coupler realized in inexpensive printed circuit board (PCB) technology is proposed. Miniaturization is achieved by exploiting the theory of right- and left-handed artificial transmission lines. The frequency agility allows the rat-race coupler to operate in two bands centered at 900 MHz and 1.7 GHz, therefore, covering many industrial and communication standards. The frequency selection is operated by CMOS switches, and controlled by only a 1-bit signal, for adapting the electrical length of the branches of the coupler. Moreover, the dimension is significantly reduced with respect to standard realizations at the same frequencies, with required areas of about 3% at 900 MHz and 10.4% at 1.7 GHz. The proposed design has been fabricated and measured, showing good performance in both operative frequency bands.