From c5dc320989b0504ee1aa44e3709e7246ed36043f Mon Sep 17 00:00:00 2001
From: Brendan Haines <brendan.haines@gmail.com>
Date: Tue, 8 Jul 2025 00:02:03 -0600
Subject: [PATCH] 2-port SOLT cal

---
 charon_vna/vna.py     | 49 +++++++++++++++++++++++++++++++++++++++----
 charon_vna/vna_dev.py | 24 ++++++++++++++++++---
 2 files changed, 66 insertions(+), 7 deletions(-)

diff --git a/charon_vna/vna.py b/charon_vna/vna.py
index fb2bc99..1a1954e 100644
--- a/charon_vna/vna.py
+++ b/charon_vna/vna.py
@@ -361,7 +361,7 @@ class Charon:
 
         return s
 
-    def calibrate_sol(self, prompt: Callable[[str], None] | None = None, **kwargs) -> rf.calibration.Calibration:
+    def calibrate_sol(self, prompt: Callable[[str], None] | None = None, **kwargs) -> None:
         if len(self.ports) != 1:
             raise ValueError(
                 f"SOL calibration needs only one port but {len(self.ports)} ports are enabled. "
@@ -378,14 +378,55 @@ class Charon:
 
         measured = list()
         for name in names:
-            prompt(f"Connect standard: {name} to port {self.ports[0]}")
+            prompt(f"Connect standard {name} to port {self.ports[0]}")
             measured.append(self.capture(**kwargs))
 
-        cal = rf.OnePort(ideals=ideals, measured=[s2net(m) for m in measured])
+        cal = rf.OnePort(measured=[s2net(m) for m in measured], ideals=ideals)
 
         self.calibration = cal
 
-        return cal
+    def calibrate_solt(self, prompt: Callable[[str], None] | None = None, **kwargs) -> None:
+        if len(self.ports) < 2:
+            raise ValueError(
+                f"SOLT calibration needs at least two ports but {len(self.ports)} ports are enabled. "
+                "Did you mean to use SOL?"
+            )
+
+        if len(self.ports) > 2:
+            raise NotImplementedError("SOLT calibration with more than two ports not yet supported")
+
+        if prompt is None:
+            prompt = lambda s: input(f"{s}\nENTER to continue...")
+
+        ideal = rf.media.DefinedGammaZ0(frequency=rf.media.Frequency.from_f(self.frequency, unit="Hz"))
+        ideals = [ideal.short(), ideal.open(), ideal.load(0)]
+        ideals = [rf.two_port_reflect(id, id) for id in ideals]
+
+        thru = np.zeros((len(self.frequency), 2, 2), dtype=np.complex128)
+        thru[:, 0, 1] = 1
+        thru[:, 1, 0] = 1
+        thru = rf.Network(frequency=self.frequency, f_unit="Hz", s=thru)
+
+        ideals.append(thru)
+
+        names_1p = ["short", "open", "load"]
+        names_2p = ["thru"]
+
+        measured = list()
+        for name in names_1p:
+            measured_param = list()
+            for port in self.ports:
+                prompt(f"Connect standard {name} to port {port}")
+                measured_param.append(self.capture(measurements=[(port, port)], **kwargs).sel(m=port, n=port))
+            measured.append(rf.two_port_reflect(*[s2net(m) for m in measured_param]))
+
+        for name in names_2p:
+            prompt(f"Connect standard {name} between ports {self.ports[0]} and {self.ports[1]}")
+            measured.append(s2net(self.capture(**kwargs)))
+
+        cal = rf.SOLT(measured=measured, ideals=ideals)
+
+        self.calibration = cal
 
     def save_calibration(self, path: Path | str):
         path = Path(path)
diff --git a/charon_vna/vna_dev.py b/charon_vna/vna_dev.py
index 9f51118..d8880f0 100644
--- a/charon_vna/vna_dev.py
+++ b/charon_vna/vna_dev.py
@@ -9,7 +9,7 @@ from charon_vna.vna import Charon
 frequency = np.linspace(80e6, 280e6, 301)
 
 # %%
-vna = Charon(frequency=frequency, ports=1)
+vna = Charon(frequency=frequency, ports=2)
 
 # %%
 s = vna.capture()
@@ -26,11 +26,19 @@ plt.show()
 # %%
 vna.calibrate_sol()
 
+# %%
+vna.calibrate_solt()
+
+# %%
+vna.save_calibration("./calibration.pkl")
+
 # %%
 vna.load_calibration("./calibration.pkl")
 
 # %%
 s2 = net2s(vna.calibration.apply_cal(s2net(s)))
+# s2.coords["m"] = s.m
+# s2.coords["n"] = s.n
 
 for m in s.m.data:
     for n in s.n.data:
@@ -39,12 +47,22 @@ for m in s.m.data:
 plt.grid(True)
 plt.legend()
 plt.ylabel("Magnitude [dB]")
+# plt.ylim(-30, 5)
 plt.show()
 
 for m in s.m.data:
     for n in s.n.data:
-        plt.plot(s.frequency, np.angle(s.sel(m=m, n=n), deg=True), label="$S_{" + str(m) + str(n) + "}$ (uncalibrated)")
-        plt.plot(s2.frequency, np.angle(s2.sel(m=m, n=n), deg=True), label="$S_{" + str(m) + str(n) + "}$ (calibrated)")
+        if m != n:
+            plt.plot(
+                s.frequency,
+                np.angle(s.sel(m=m, n=n), deg=True),
+                label="$S_{" + str(m) + str(n) + "}$ (uncalibrated)",
+            )
+            plt.plot(
+                s2.frequency,
+                np.angle(s2.sel(m=m, n=n), deg=True),
+                label="$S_{" + str(m) + str(n) + "}$ (calibrated)",
+            )
 plt.grid(True)
 plt.legend()
 plt.ylabel("Phase [deg]")