Periodic Synthesized Transmission Lines With 2-D Routing Capability and Its Applications to Power Divider and Couplers Using Integrated Passive Device Process

A novel periodic synthesized transmission line, comprising periodic unit cells and specially treated corner cells, is proposed and realized using integrated passive device technology. The key innovation is the square unit cell, formed by an asteriated strip overlapped with a capacitive pad. It enables 2-D layout routing since any two of the four arms of the unit cell can serve as the input/output ports. To account for the discontinuity effect at bends, the corner cells are developed independently as a pure lumped T-network to reduce the undesired signal reflection at junctions. Quarter-wavelength synthesized lines are jointed together as miniaturized on-chip couplers. The experimental results demonstrate the compactness of the on-chip components, in addition to their good electrical responses. The uniqueness of the design concept is clearly validated.