S-Parameter Viewer

Chart controls. Wheel to zoom around the cursor; drag the frequency chart to pan. Full range restores the complete sweep. Grid changes apply immediately; Axes sets manual limits. The zoom and pan buttons provide keyboard alternatives.

Pin and cursor. Filled diamonds stay pinned; hollow circles follow the cursor. Find selects the sample file’s minimum or maximum over its full sweep: magnitude in Magnitude and Smith views, unwrapped phase in Phase view. Equal extrema use the lowest frequency; undefined values are skipped. For reflection traces, Lower edge and Upper edge use the −10 dB band nearest the pin over the full sweep. The menu shows estimated crossings; each action pins the nearest supplied sample inside that band, so readings use supplied samples and both actions keep the same band. Missing crossings are disabled without extrapolation. A hidden sample file is shown when a result is selected. Offscreen results pan into view while retaining the zoom span and vertical limits. Drag the pin, step through the sample file’s points, or enter a pin frequency and press Enter or Go. Escape cancels an uncommitted frequency edit. Hover previews update the readings without moving the pin; on a Smith chart, click a supplied point to select its file and pin it.

Reading Sij. Response at port i for excitation at port j, with every other port matched. Diagonal terms are reflection; off-diagonal terms are transmission. The Smith grid shows normalized impedance for the selected reflection term; equal positions can mean different impedances when file references differ.

Comparing files. Readings use each file’s nearest supplied sample within its sweep. Lines connect samples; they add no measurements. Compare compatible calibration, fixtures and reference planes. No renormalization or de-embedding is applied.

Phase. Wrapped phase lies between −180° and +180°; unwrapped phase removes 360° display jumps. Files unwrap independently: different starting frequencies or gaps can shift branches by whole 360° turns. Sparse sampling can hide whole turns. Zeros have no phase, so undefined samples break the affected phase trace.

Group delay. Delay is estimated from sampled, nearest-branch unwrapped phase. Sparse sampling, zeros and 180° steps can make it unreliable; endpoints use one-sided estimates. Reflection delay is not propagation time.

−10 dB match bandwidth. Match bandwidth is the upper edge minus the lower edge of a contiguous band with reflection at or below −10 dB. The magnitude chart shows this reference level for imported files and examples whenever it lies within the vertical limits. Edges are estimated by linear interpolation of reflection magnitude between adjacent supplied samples; plotted connecting lines remain illustrative. The comparison is in More measurements and includes all loaded files. For multiple bands, it uses the band nearest the pin across the full sweep, independent of zoom and hover. An incomplete band needs both edges to be identified; no extrapolation is applied at sweep boundaries or across unavailable data. Coarse samples can miss narrow bands. This describes impedance matching; radiation efficiency requires separate data.

Supported files. ASCII Touchstone 1.0 and 2.0 Full matrices, 1–32 single-ended ports, RI / MA / DB, Hz–GHz, increasing frequencies with optional initial DC. One equal positive real reference at all ports. Mixed mode, triangular matrices, noise blocks, unequal/complex references and 2.1 extensions are unsupported.

8 files · 2 MB, 100,000 lines, 20,000 frequency samples and 262,144 complex entries per file · 1,048,576 entries combined. Files stay in this browser. CSV exports the sample file’s full selected-parameter sweep.