Realization and calibration for 67GHz wideband harmonic phase reference

As the most important measurement channel of nonlinear vector network analyzer (NVNA), the harmonic phase reference (HPR) can provide the ability of measuring the absolute phase information for the multi-frequency situations. A prototype HPR based on the nonlinear transmission lines (NLTLs) is designed. The complete phase calibration procedure for 67GHz wideband HPR is also proposed, including the time-base distortion, the average de-noising, the phase alignment, the connector mismatch and the frequency response corrections. The calibration experiment results show that, an impulse sequence with pulse width less than 22 ps and 67 GHz frequency bandwidth is obtained, where the prototype HPR was excited by a 1 GHz sinusoidal signal with 27 dBm input power. Moreover, the phase accuracy and repeatability are less than ±10° and ±5° degree in the highest harmonic components, respectively. Finally, the comparison results between NVNA-based (with prototype HPR) and oscilloscope-based measurement, for the output time-domain waveform of the narrow-time-width pulse generator under a 2 GHz signal exciting, prove that the validity and efficiency of the proposed realization and calibration techniques.