Impedance-measurement parameters Resolution

This chip die sizes are 5 X 5 and 10 X 10 mm. The first chip (5X5 mm ) of the spectrometer, the front-end chip, has the local oscillator together with the SIS mixer and impedance matching structure for better power delivery and to time out the SIS junction capacitance. The frequency resolution of SISP determined by both the instant linewidth of the LO and its long-time stability along with the noise temperature is one of the major parameters in spectral measurements. The phase-lock loop consisted both on-chip circuitry and room-temperature electronics is employed. ... 

Another problem is that the transmission line is modeled in time domain, so some important frequency-dependent parameters can t be exactly represented. These parameters can only be approximated and idealized in order to simplify the simulation process. These approximations lead to critical errors due to divergence of the parameter extraction. Consequently, the measurement system is not efficient and don t realize a sufficient accuracy. Furthermore, the impulse response is derived from the scattering parameter SI 1, which is measured in the frequency domain and transformed to the time-domain. This is critical for the resolution and computational time. In [23] only the wire faults with open circuits and some special impedance changes are estimated. 

---