Experimental results of on-chip center-tapped microwave transformers

On-chip center-tapped microwave transformers of different dimensions were designed, processed on GaAs substrates, and measured on-wafer with an S-parameter analyzer and a sampling oscilloscope. The experimental results indicate that on-chip microwave center-tapped transformers can be designed for applications in the frequency range from a few hundred MHz up to more than 50 GHz with an endurable insertion loss. These results are useful for MMIC designs.