Measurement of the Modulated Scattering Microwave Fields Using Dual-Phase Lock-in Amplifier

Abstract

The new automatic measurement architecture is proposed for the simultaneous measurement of the amplitude and phase of microwave fields with optically modulated scatterer. The modulated scattering techniques have been popularly used for rapid electric field measurement without scarifying the acceptable level of accuracy. However, the conventional system for measurement of the modulated scattering fields has an unstable measurement ability and a measurement limitation in terms of a wide band frequency range due to the imperfection of in-phase and quadrature phase operation of the coupler. In this letter, we propose the improved measurement system using two signal generators. The measurement results of the proposed system are compared with those of the conventional system to demonstrate the superior performance with the phase prediction result in the near and far-field range and to validate performance of the proposed system.