Parametric analysis of improved planar balun circuits for wireless microwave and RF applications

The high frequency balun network is a vital component in the realization of certain RF and microwave system topologies, especially in wireless communication system architectures. This paper describes an in-depth parametric analysis of two planar balun circuits operating in the 900 MHz wireless band. The novel feature of the designs are their compact size which is almost one-tenth of the standard λ/4 coupled line design. Coupling levels for the two designs are ~6 dB (with broader bandwidth) for Model 1 and ~3 dB (with narrower bandwidth) for Model 2. Computed and measured data are presented for coupling performance, and dimensional parametric analysis