Adopting the broadside coupled line for the design of an impedance transformer

A compact impedance transformer with the broadside coupled line is provided in this paper. With the assistant of the proposed broadside coupled line, the electrical length of the impedance transformer would be smaller than a quarter wavelength. In addition, analytic equations for the design of complex impedance transformer are derived; optimal characteristic impedance and transformation ratio for successful power transfer are calculated as well. Results of simulation and measurement demonstrate the efficient transformation and the potential for applications to radio frequency and microwave circuits.