A novel reconfigurable coupler for intelligent SOP RF front-ends

A novel class of planar reconfigurable directional couplers for intelligent system on package (SOP) RF front-ends is presented. Reconfigurability is obtained by modifying the electrical parameters of the coupled lines so as to tune the coupling ratio. RF switches such as MEMS or PIN diodes can be used to enable a wide range of reconfigurability in a very compact and low-loss device. The performance and the limitations of the coupler are discussed and design equations are provided. A hardwired prototype in microstrip technology has been manufactured. The novel concept introduced, however, is technology independent so that the reconfigurable coupler can be fabricated in microstrip, stripline or coplanar configurations.