IP3 Measurements of Liquid Crystals at Microwave Frequencies

The nonlinear behaviour of a phase shifter employing two different nematic liquid crystals (NLCs) as a tunable dielectric is investigated in this work. The NLCs used are the quasi-standard NLC 5CB and a highly anisotropic mixture MDA-03-2844. The third order intercept point IP3 was measured at 7.4 GHz. The utilized measurement setup allows the application of 40 dBm total power to the device under test (DUT) with an IP3 of the empty setup of at least 60 dBm. The output IP3 is at least 52 dBm for 5CB and 58 dBm for the mixture. The proposed phase shifter design therefore exhibits high linearity