Non-linear phase shifter using composite right/left-handed transmission line on dielectric substrate

In multi-band base station antennas, interference toward neighboring cells at low operating frequency increases since tilting angle is frequency-independent and beamwidth in the vertical plane increases as decreasing the operating frequency. This paper presents a new low-profile phase shifter which comprises non-linear frequency-dependent characteristics. The proposed phase shifter is composed of the composite right/left-handed transmission line configured by the series interdigital capacitor and shunt meander inductor printed on thin dielectric substrate. Bloch impedance and dispersion characteristics are investigated at two frequencies simultaneously. Non-linear frequency-dependent characteristics with large phase shift is confirmed through the electromagnetic simulation.