Coupled microstrip line Wilkinson power divider with open-stubs for compensation
Coupled microstrip line section is a well-known technology for various circuits miniaturisation. Because the phase velocity difference of coupled microstrip line section exists in practical circuit, compensation method is needed to maintain circuit performance. In this Letter, extra open-stubs are newly inserted between coupled microstrip line section and two output ports for compensation. Compared with previous work, by using open-stubs, a novel and flexible compensation method is newly presented, where, both Γev and Γod are adjusted for compensation at the same time, the proposed circuit not only provides simple structure and easy fabrication but also compensates arbitrary coupling strength without soldering parasitic effect in high frequency operation. Through even- and odd-mode analysis, design equations are derived and discussed in Smith chart. In experiment, one circuit was fabricated, the measurement results showed good agreement with theoretical results.
