Dual-band quadrature hybrids using 1/8-wavelength composite right/left-handed transmission lines

In this paper, dual-frequency 90° hybrids consist of 1/8 wavelength composite right/left-handed (CRLH) transmission lines are proposed. Two hybrids are designed and fabricated to operates at 1.8 GHz and 3.5 GHz. One uses the 1/8- and 3/8-wavelength modes, while the other uses -1/8- and 1/8-wavelength modes. Measured results indicate that good performance is achieved.