plotRefl
========
```{function}  plotRefl(port,varargin)
```
Full definition:
```{code-block} matlab
h = plotRefl(port,varargin)
```

 plot the reflection coefficient of a port into a Smith chart.
 left and right facing triangles mark the lower and upper cutoff
 frequency of the pass bands. An asterisk marks the frequnecy with 
 the lowest reflection.

input:
-  port:      port data structure. Call calcPort with an appropriate 
              frequency vector before calling this routine

output:      graphics handle for further modification of the plot.

variable input:
- 'precision':     number of decimal places (floating point precision) 
                    for the frequency (always in MHz), default is 0
- 'threshold':     Threshold value (in dB) for the upper and lower
                    cutoff frequency, default is -3
- 'fmarkers':      set lower and upper frequency marker in Hz manually, 
                   like so: [4e9, 6.5e9]

example:

    myport = calcPort(myport, Sim_Path, linspace(f_0-f_c, f_0+f_c, 200));
    plotRefl(myport, 'fmarkers', [4e9, 6.5e9]);

See also calcPort



-----------------------
author: Georg Michel