Multiline Thru-reflect-line Calibration Research Articles

Electronic Calibration for Submillimeter-Wave On-Wafer Scattering Parameter Measurements Using Schottky Diodes

A proof-of-concept demonstration of on-wafer electronic calibration in the submillimeter-wave band (325–500 GHz) is presented. A GaAs Schottky diode shunting a coplanar transmission line is employed as an electronic standard that is tuned by bias applied through wafer probes. Error-corrected scattering parameter measurements, based on a Thru-Reflect-Line (TRL) calibration, are used to characterize the on-wafer diode and establish it as a standard for electronic calibration. Subsequently, ensembles of measurements from a multiline TRL calibration and the diode calibration standard are performed and compared to assess the uncertainty associated with the two approaches. It is found that the error coefficients estimated using the electronic standard are in good agreement with those found from the multiline TRL calibration. Moreover, the electronic standard exhibits a significant improvement in precision compared with the TRL standards, consistent with previous work showing that error in probe placement between measurements was a principle source of uncertainty for TRL-based calibration.

Monte Carlo Analysis of Measurement Uncertainties for On-Wafer Multiline TRL Calibration Including Dynamic Accuracy

The multiline thru-reflect-line (TRL) calibration algorithm model is used to determine the error sources and uncertainties for on-wafer S-parameter measurements, and the uncertainty source is presented in a diagrammatic form. The quantitative contribution of each input error source to the S-parameter of the device under test (DUT) is obtained through the Monte Carlo method. Through analysis, it is found that the dynamic accuracy of the vector receiver as an ignored source of uncertainty makes a significant contribution to the amplitude of transmission coefficients and large reflection coefficient of the on-wafer S-parameters. Finally, the influence of dynamic accuracy measurement error on the DUT with different reflection coefficients is studied.

Development of gallium-arsenide-based GCPW calibration kits for on-wafer measurements in the W-band

AbstractWe present details of on-wafer-level 16-term error model calibration kits used for the characterization of W-band circuits based on a grounded coplanar waveguide (GCPW). These circuits were fabricated on a thin gallium arsenide (GaAs) substrate, and via holes, were utilized to ensure single mode propagation (i.e., eliminating the parallel-plate mode or surface mode). To ensure the accuracy of the definition for the calibration kits, multi-line thru-reflect-line (MTRL) assistant standards were also fabricated on the same wafer and measured. The same wafer also contained passive and active devices, which were measured subject to both 16-term and conventional line-reflect-reflect-match calibrations. Measurement results show that 16-term calibration kits are capable of determining the cross-talk more accurately. Other typical calibration techniques were also implemented using the standards on the GCPW calibration kits, and were compared with the MTRL calibration using a passive device under test. This revealed that the proposed GCPW GaAs calibration substrate could be a feasible alternative to conventional CPW impedance standard substrates, for on-wafer measurements at W-band and above.

A Multireflect-Thru Method of Vector Network Analyzer Calibration

We present a new method for two-port vector network analyzer (VNA) calibration, which uses multiple offset-reflect standards and a flush thru connection. Offset-reflect standards consist of sections of the same uniform transmission line with different lengths, which are terminated with the same highly reflective load. The unknown propagation constant of the transmission line and the load reflection coefficient are then determined simultaneously with the VNA calibration coefficients. We compare our method with the multiline thru-reflect-line (TRL) method and show that both methods yield similar results. Our new multireflect-thru method is solely based upon dimensional parameters of the calibration standards. Therefore, like the multiline TRL method, it can be used to establish a traceable VNA calibration. Thus, the multireflect-thru method constitutes an alternative to the multiline TRL calibration in environments in which the use of transmission lines is troublesome, such as in the case of VNAs with very small coaxial and waveguide connectors. The multireflect-thru method is also useful in on-wafer measurements since it allows us to keep a constant distance between the probes, which reduces the impact of crosstalk and speeds up automated testing.

Comparison of on-wafer calibrations for THz InP-based PHEMTs applications**Project supported by the National Natural Science Foundation of China (No. 61275107).

A quantitative comparison of multiline TRL (thru-reflect-line) and LRM (line-reflect-match) on-wafer calibrations for scattering parameters (S-parameters) measurement of InP-based PHEMTs is presented. The comparison is undertaken for the first time and covers a frequency range from 70 kHz to 110 GHz. It is demonstrated that the accuracy of multiline TRL and LRM calibration is in good agreement. Both methods outperform the conventional SOLT calibration in the full frequency band up to 110 GHz. Then the excellent RF performance is obtained by extrapolation on the basis of inflection point, including a maximum current gain cut-off frequency ft of 247 GHz and a maximum oscillation frequency fmax of 392 GHz. The small-signal model based on LRM calibration is established as well. The S-parameters of the model are consistent with the measured from 1 to 110 GHz.

Broadband Complementary Metal-Oxide Semiconductor Interconnection Transmission Line Measurements With Generalized Probe Transition Characterization and Verification of Multiline Thru-Reflect-Line Calibration

This paper presents extraction techniques and measurement results for broadband complementary metal-oxide semiconductor (CMOS) interconnection transmission line (TL) measurements with generalized probe transition characterization and verification of multiline thru-reflect-line (TRL) calibration. Initially, the probe transition is represented by a transmission matrix instead of the conventional shunt/series model, with detailed parameter evaluation procedures using measured data from two lines that are twice in length. Subsequently, an additional long TL that fully exhibits the TL characteristics at low frequencies is characterized, whereas the matrix manipulations with the other two TL measured data are adapted for high-frequency regions to avoid the ill-conditioned problem. Consequently, broadband characterization for CMOS TL is achieved in a cost-effective manner. With an additional reflect test structure, the multiline TRL calibration can be performed as well for verification. The proposed method is examined by thin-film microstrip lines using CMOS 90-nm one-poly/nine-metal technology with measurement frequencies from 2 to 110 GHz.

The Impact of On-Wafer Calibration Method on the Measured Results of Coplanar Waveguide Circuits

This paper compares four commonly used on-wafer calibration methods including multiline thru-reflect-line (TRL), line-reflect-reflect-match, line-reflect-match, and short-open-load- thru, for three diverse coplanar waveguide (CPW) circuits. The magnitudes and phases of S 11 and S 21 of the CPW circuits are compared to quantify how the specific calibration method influences measured scattering parameters. Special care is taken to ensure that the measured scattering parameters are normalized to the same reference impedance and reference plane for accurate comparison. The measured results are compared with full-wave simulations to provide additional assessment of accuracy. A method to de-embed the discontinuity of the CPW at the probe tip and the CPW of the test structures is presented. The effect of probe-to-device-under-test discontinuity is effectively modeled by one- or two- section of shunt capacitor and series inductor. The results show that the multiline TRL calibration method provides the highest transmission coefficient repeatability on not well-matched circuits and highest accuracy on the three circuits in this paper up to 40 GHz.