# Source/Load-Pull Noise Measurements at K\({}_{\text{a}}\) [PERSON]
## 3 Results
The effect of increasing \(B_{L}\), as mentioned in Section 2.4 consists in allowing more source (in forward mode) and output (in reverse mode) terminations to contribute to each extraction. As an example, the extractions at \(f_{0}=35\) GHz with \(B_{L}=1\) GHz and \(B_{L}=5\) GHz are shown in Figure 5. It is evident that the number of terminations and their spreading across the reflectance plane improves significantly with higher and higher values of \(B_{L}\). To further illustrate this effect, extractions with different settings are compared in Table 1 at the target frequency \(f_{0}=35\) GHz (a nearby frequency is shown when the extraction fails at 35 GHz). In particular, the first three columns present the extraction failure rate versus \(B_{L}\) and the exploited configuration. The term 'failure rate' here denotes the ratio of the number of frequencies associated with physically sensible extractions to the total number. It is evident that in the given scenario the failure rate drops to very low values, even with moderate bandwidths (\(B_{L}\geq 0.5\) GHz), when both forward (FWD) and reverse (RVS) configurations are adopted. The remaining columns provide the actual frequency and the extracted noise parameters. Among the considered settings, notice that those presented in the last row of Table 1 correspond to a standard source-pull approach with the minimum number of terminations. Similarly, the third row corresponds to a semi-standard approach exploiting both source- and load-pull data. Thus, these two rows can serve as a familiar term of comparison for the full-blown methodology presented in this contribution. Although the data in Table 1, being referred to one single target frequency, can only give an incomplete picture of the state of affairs, nevertheless they allow to illustrate some of the differences between the two regimes. Figure 4: Conversion of the noise correlation matrix to the noise parameters over frequency. Points: physically sound subset of the standard extraction. Continuous thin lines: linearization-based extraction (\(f_{1}=f_{0}-0.5\) GHz, \(f_{2}=f_{0}+0.5\) GHz). Continuous thick lines: linearization-based extraction (\(f_{1}=f_{0}-2.5\) GHz, \(f_{2}=f_{0}+2.5\) GHz). Figure 5: Example of termination pattern for the extraction of the noise parameters at \(f_{0}=35\) GHz. The terminations form groups depending whether they are associated with frequencies lower than \(f_{0}\) (\(\prec\)), equal to \(f_{0}\) (\(=\)) or higher than \(f_{0}\) (\(\succ\)), and whether they refer to the forward (FWD) or reverse (RVS) mode. In this particular case, the forward mode \(\Gamma_{S}\) reflectances and the reverse mode \(\Gamma^{\prime}_{out}\) reflectances happen to be inside and outside of the passive Smith chart, respectively. The black point represents the optimum point \(\Gamma_{opt}\). overall trends. First of all, the 4-termination standard approach (row 6) is seen to be unreliable in this case: besides an unsatisfactory failure rate, the noise parameters which it yields are quite off as compared to the the first four rows. This situation improves only slightly for row 5, which approximately corresponds to a standard approach with a higher number of source terminations. Broadening \(B_{L}\) further, as in row 4, still results in a mediocre failure rate; however, the noise parameters now get to yield, together with the first three rows, a consistent bulk of extractions. Merging source- and load-pull data in one single extraction seems to produce generally good results with all choices of \(B_{L}\), and in particular even with \(B_{L}=0\) GHz [10], as in row 3. However, larger and larger bandwidths \(B_{L}\) also yield smoother traces and considerably lower failure rates, as in rows 2 and 1. In addition to the reference drain current \(I_{D}=17.1\) mA, similar extractions were performed at other current values, namely 34.2 mA, 51.2 mA and 68.3 mA.