circle

Draw circles on Smith Chart

Description

example

[hsm_out] = circle(rfcktobject,freq,type1,value1,....,typen,valuen,hsm1_out) draws the specified circles on a Smith chart created using the smithplot function. The syntax returns an existing smithplot handle.

[hlines,hsm] = circle(rfcktobject,freq,type1,value1,....,typen,valuen,hsm_out) draws the specified circles on a Smith chart. This syntax returns vector handles of line objects and handles of the Smith chart.

Examples

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Create an amplifier object from default.s2p.

amp = read(rfckt.amplifier,'default.s2p');

Plot the noise figure of the amplifier 1.9 GHz using a Smith chart created using smithplot function

fc = 1.9e9;
h = smithplot
h = 
  smithplot with properties:

         Data: []
    Frequency: []

   Show all properties, methods

circle(amp,fc,'Stab','In','Stab','Out','NF',10.396,h);
legend('Location','SouthEast')

Input Arguments

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RF Toolbox rfckt object, specified as an object handle,

Single frequency point of interest, specified as a scalar in Hz.

Data Types: double

Type value pairs specifying circles to plots, specified as a character vector.

The following table lists the supported circle type options:

typeDefinition
'Ga'Constant available power gain circle
'Gp'Constant operating power gain circle
'Stab'Stability circle
'NF'Constant noise figure circle
'R'Constant resistance circle
'X'Constant reactance circle
'G'Constant conductance circle
'B'Constant susceptance circle
'Gamma'Constant reflection magnitude circle

The following table lists the circle value options:

valueDefinition
'Ga'Scalar or vector of gains in dB
'Gp'Scalar or vector of gains in dB
'Stab''in' or 'source' for input/source stability circle; 'out' or 'load' for output/load stability circle
'NF'Scalar or vector of noise figures in dB
'R'Scalar or vector of normalized resistance
'X'Scalar or vector of normalized reactance
'G'Scalar or vector of normalized conductance
'B'Scalar or vector of normalized susceptance
'Gamma'Scalar or vector of non-negative reflection magnitude

Data Types: char

Existing Smith chart handle created using smithplot function, specified as an object handle. You can obtain the object handle using hsm1 = smithplot('gco').

Existing Smith chart handle, specified as an object handle.

Output Arguments

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Line objects for circle specifications, returned as a vector of line handles.

Smith chart, returned as an object handle.

Smith chart created using smithplot function, returned as an object handle.

Introduced in R2007b