In the first two plots, the two shorted OMTs were attached as closely as I could get them, but not taped together (Figure 1a) (see paragraph below for the implications of not taping them together). This was compared against the 1/16th and 1/8th inch acrylic inserted between the two OMTs (Figure 1b). In the lower two plots, the same acrylic measurements are plotted, but this time they are plotted against a gap of their respective widths, instead of against the two OMTs placed flat against each other. The point of this second measurement was to see if the effects present in the first plots were actually a result of the separation of the two OMTs, and not because of the acrylic presence (this turns out not to be the case, at least it seems).
Shorted OMT S21 measurement with/without acrylic
Zoom on interest area
1/16th and 1/8th inch gaps vs. 1/6th and 1/16th and 1/8th inch acrylic
Zoom on interest area
Some things to note immediately: the shorted OMTs are VERY sensitive to holes and other gaps. I noticed that whenever there was an unsecured gap, such as when I took the 1/16th and 1/8th inch gap measurements, simply moving my hands around the area between the two OMTs (but not blocking anything or sticking my hand in between) produced a noticeable change in the data. This was similar when the acrylic was in place, as well. Even though I tried to secure it as much as possible, the data reacted to me moving my hand around the acrylic just as it had to me moving my hand around a gap.
While this is an important thing to consider, the data still shows relatively clear patterns, such as some significant changes in two regions: the region on which I zoomed in for both plots, as well as around 0.9 GHz. I'm not exactly sure of the significance of this, I am just bringing attention to it.
NOTE: None of the preceding plots were made with an absorber sheet present. I changed this starting at this point.
Now, at this point I realized (or was guided by Chris) that changing the gap width is a bad practice. This next plot involves an unchanged gap size at about 1/2 of an inch, with 1/16th inch acrylic and 1/18th inch acrylic added but the OMTs held still.
In the first two plots, the two shorted OMTs were attached as closely as I could get them, but not taped together (Figure 1a) (see paragraph below for the implications of not taping them together). This was compared against the 1/16th and 1/8th inch acrylic inserted between the two OMTs (Figure 1b). In the lower two plots, the same acrylic measurements are plotted, but this time they are plotted against a gap of their respective widths, instead of against the two OMTs placed flat against each other. The point of this second measurement was to see if the effects present in the first plots were actually a result of the separation of the two OMTs, and not because of the acrylic presence (this turns out not to be the case, at least it seems).
Some things to note immediately: the shorted OMTs are VERY sensitive to holes and other gaps. I noticed that whenever there was an unsecured gap, such as when I took the 1/16th and 1/8th inch gap measurements, simply moving my hands around the area between the two OMTs (but not blocking anything or sticking my hand in between) produced a noticeable change in the data. This was similar when the acrylic was in place, as well. Even though I tried to secure it as much as possible, the data reacted to me moving my hand around the acrylic just as it had to me moving my hand around a gap.
While this is an important thing to consider, the data still shows relatively clear patterns, such as some significant changes in two regions: the region on which I zoomed in for both plots, as well as around 0.9 GHz. I'm not exactly sure of the significance of this, I am just bringing attention to it.
NOTE: None of the preceding plots were made with an absorber sheet present. I changed this starting at this point.
Now, at this point I realized (or was guided by Chris) that changing the gap width is a bad practice. This next plot involves an unchanged gap size at about 1/2 of an inch, with 1/16th inch acrylic and 1/18th inch acrylic added but the OMTs held still.
Appendix