circuitRF Reference Guide

Plot Types

The Data Display offers four plot types. Which one you can use depends on whether the data is real (scalar) or complex — that's the single most important rule below.

Scalar vs. complex — the rule

Rectangular shows scalar (real) data only. Smith and Polar show complex data only. Table is the exception — it shows both complex and scalar data together in one grid. So a complex quantity like S(1,1) goes on a Smith/Polar/Table; a real quantity like Pout in dBm goes on a Rectangular/Table; and a Table can hold both at once.

Rectangular

The familiar Cartesian X–Y plot. Scalar data only. A complex signal must be reduced to a real quantity first via a per-trace transform — magnitude in dB (dB20/dB10), phase in degrees, real part, imaginary part, magnitude. This is the plot for gain vs. frequency, Pout vs. drive, efficiency vs. load, harmonic levels, and most swept results.

circuitRF - Data Display SParameters circuitRF 2 4 6 8 10 2 4 6 8 10 12 freq (GHz) SP1.S(2,1) dB20 circuitRF - Data Display SParameters circuitRF 2 4 6 8 10 2 4 6 8 10 12 freq (GHz) SP1.S(2,1) dB20
A rectangular plot of the shipped FET test bench's S-parameters, 1-10 GHz.

Smith

The Smith chart maps impedance/reflection onto the unit disk. Complex data only — it plots the complex value directly (no transform needed). Use it for reflection coefficients (S(1,1)), input/output impedance, and matching-network design. Loadpull contours are drawn on the Smith chart's Γ-plane.

circuitRF - Data Display SParameters circuitRF SP1.S(1,1) 1 0.5 2 5 10 1 -1 0.2 -0.2 0.5 -0.5 2 -2 5 -5 10 -10 freq (1 to 10 GHz) circuitRF - Data Display SParameters circuitRF SP1.S(1,1) 1 0.5 2 5 10 1 -1 0.2 -0.2 0.5 -0.5 2 -2 5 -5 10 -10 freq (1 to 10 GHz)
A Smith chart carrying the FET test bench's own S(1,1), swept 1-10 GHz.

Polar

A magnitude-and-angle plot on concentric circles. Complex data only. Use it when you care about a complex quantity's phase and magnitude but don't want the Smith chart's impedance grid — e.g. viewing a reflection or transmission coefficient as a vector.

circuitRF - Data Display SParameters circuitRF SP1.S(2,1) 3.8912 3 2 1 freq (1 to 10 GHz) circuitRF - Data Display SParameters circuitRF SP1.S(2,1) 3.8912 3 2 1 freq (1 to 10 GHz)
The same run on a polar plot: magnitude and angle, without the impedance grid.

It is also where a node's stability is read. The reference document behind the WSProbe reads 1/H0 and 1/Y0 on a polar chart and looks for a clockwise crossing of the negative real axis — so those two, and the envelope's 1/H0env and 1/Y0env, are offered on Polar and on nothing else. An Ohtomo global loop gain is polar-only for the same reason, with one difference that matters: its critical point is +1, not the origin. A polar plot carrying any WSProbe trace draws small reference marks at both points, because a reader who has to remember which family reads against which is a reader who will occasionally use the wrong one.

Table

The numbers in a grid. Table is special: it shows complex and scalar data simultaneously in the same table — something no other plot type does. A complex column displays in a chosen complex format (magnitude/angle, real/imag, or dB/angle), and a scalar column shows its real value, side by side. It's ideal for reading exact values, building a results summary, and copying data out. (The loadpull summary table is a specialized Table view.)

circuitRF - Data Display SParameters circuitRF freq (GHz) SP1.S[:, 2, 1] SP1.S[:, 1, 1] 1.000 4.007 ∠ 162.6° 1.000 ∠ -34.9° 1.090 3.973 ∠ 161.1° 1.000 ∠ -37.8° 1.180 3.938 ∠ 159.7° 1.000 ∠ -40.7° 1.270 3.901 ∠ 158.2° 1.000 ∠ -43.5° 1.360 3.862 ∠ 156.9° 1.000 ∠ -46.3° 1.450 3.822 ∠ 155.5° 1.000 ∠ -49.0° 1.540 3.781 ∠ 154.2° 1.000 ∠ -51.6° 1.630 3.738 ∠ 152.9° 1.000 ∠ -54.2° 1.720 3.695 ∠ 151.6° 1.000 ∠ -56.8° 1.810 3.651 ∠ 150.4° 1.000 ∠ -59.2° 1.900 3.606 ∠ 149.2° 1.000 ∠ -61.7° 1.990 3.561 ∠ 148.0° 1.000 ∠ -64.0° 2.080 3.516 ∠ 146.8° 1.000 ∠ -66.3° 2.170 3.470 ∠ 145.7° 1.000 ∠ -68.6° 2.260 3.424 ∠ 144.6° 1.000 ∠ -70.7° 2.350 3.379 ∠ 143.6° 1.000 ∠ -72.9° 2.440 3.333 ∠ 142.5° 1.000 ∠ -74.9° 2.530 3.288 ∠ 141.5° 1.000 ∠ -77.0° 2.620 3.243 ∠ 140.5° 1.000 ∠ -78.9° 2.710 3.198 ∠ 139.6° 1.000 ∠ -80.8° 2.800 3.153 ∠ 138.7° 1.000 ∠ -82.7° 2.890 3.109 ∠ 137.8° 1.000 ∠ -84.5° 2.980 3.066 ∠ 136.9° 1.000 ∠ -86.2° 3.070 3.023 ∠ 136.0° 1.000 ∠ -87.9° circuitRF - Data Display SParameters circuitRF freq (GHz) SP1.S[:, 2, 1] SP1.S[:, 1, 1] 1.000 4.007 ∠ 162.6° 1.000 ∠ -34.9° 1.090 3.973 ∠ 161.1° 1.000 ∠ -37.8° 1.180 3.938 ∠ 159.7° 1.000 ∠ -40.7° 1.270 3.901 ∠ 158.2° 1.000 ∠ -43.5° 1.360 3.862 ∠ 156.9° 1.000 ∠ -46.3° 1.450 3.822 ∠ 155.5° 1.000 ∠ -49.0° 1.540 3.781 ∠ 154.2° 1.000 ∠ -51.6° 1.630 3.738 ∠ 152.9° 1.000 ∠ -54.2° 1.720 3.695 ∠ 151.6° 1.000 ∠ -56.8° 1.810 3.651 ∠ 150.4° 1.000 ∠ -59.2° 1.900 3.606 ∠ 149.2° 1.000 ∠ -61.7° 1.990 3.561 ∠ 148.0° 1.000 ∠ -64.0° 2.080 3.516 ∠ 146.8° 1.000 ∠ -66.3° 2.170 3.470 ∠ 145.7° 1.000 ∠ -68.6° 2.260 3.424 ∠ 144.6° 1.000 ∠ -70.7° 2.350 3.379 ∠ 143.6° 1.000 ∠ -72.9° 2.440 3.333 ∠ 142.5° 1.000 ∠ -74.9° 2.530 3.288 ∠ 141.5° 1.000 ∠ -77.0° 2.620 3.243 ∠ 140.5° 1.000 ∠ -78.9° 2.710 3.198 ∠ 139.6° 1.000 ∠ -80.8° 2.800 3.153 ∠ 138.7° 1.000 ∠ -82.7° 2.890 3.109 ∠ 137.8° 1.000 ∠ -84.5° 2.980 3.066 ∠ 136.9° 1.000 ∠ -86.2° 3.070 3.023 ∠ 136.0° 1.000 ∠ -87.9°
A table of the same run, a complex column beside a scalar one.

Adding traces & transforms

Each plot holds one or more traces, configured in the trace card:


See also: Simulations (what each analysis produces) · Components.