Broadband Quadrature Hybrid Design Using Metamaterial Transmission Line and Its Application in the Broadband Continuous Phase Shifter

This paper presents a broadband quadrature hybrid which makes use of the broadband power division properties of conventional Wilkinson power splitters along with broadband phase difference achieved using metamaterial based delay lines. The bandwidth of the 90degplusmn5deg phase difference and 0.48 dB power difference between the outputs of the Wilkinson power splitter and metamaterial delay line combination is 67%. The full four-port coupler is formed employing an additional combiner. A phase/power difference between the hybrid outputs of 90degplusmn10deg and 1.2 dB, respectively, are observed over the same 67% bandwidth. To demonstrate the applicability of the proposed broadband quadrature hybrid, a continuous phase shifter which is based on the vector sum method is tested.