# charge

Calculate and plot charge distribution

Since R2021b

## Description

charge(rfpcbobject,frequency) calculates and plots the absolute value of the charge in C/m on the metal surface of a PCB component at the specified frequencies.

example

c = charge(rfpcbobject,frequency) calculates a vector of charges in C/m on the metal surface of a PCB component, at the specified frequencies.

[c,p] = charge(rfpcbobject,frequency) returns the point at which the charge calculation was performed.

charge(rfpcbobject,frequency,'dielectric') calculates and plots the absolute value of the charge at the specified frequency on the dielectric surface of the PCB component.

c = charge(rfpcbobject,frequency,'dielectric') calculates the charge on the dielectric surface of a PCB component at the specified frequency.

c = charge(___,Name=Value) calculates the charge on the surface of a PCB component using additional name-value arguments.

## Examples

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Create a rat-race coupler with default properties.

coupler = couplerRatrace;

Set the feed voltage and phase at the coupler ports.

v = voltagePort(4)
v =
voltagePort with properties:

NumPorts: 4
FeedVoltage: [1 0 0 0]
FeedPhase: [0 0 0 0]
PortImpedance: 50

v.FeedVoltage = [1 0 1 0]
v =
voltagePort with properties:

NumPorts: 4
FeedVoltage: [1 0 1 0]
FeedPhase: [0 0 0 0]
PortImpedance: 50

v.FeedPhase = [90 0 270 0]
v =
voltagePort with properties:

NumPorts: 4
FeedVoltage: [1 0 1 0]
FeedPhase: [90 0 270 0]
PortImpedance: 50

Calculate and view the charge distribution of the coupler at 3 GHz.

figure
charge(coupler,3e9,Excitation=v)

## Input Arguments

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PCB component object, specified as an RF PCB object. For a complete list of the PCB components and shapes, see PCB Components Catalog and Custom Geometry and PCB Fabrication.

Frequency to calculate charge distribution in hertz, specified as a scalar.

Example: 70e6

Data Types: double

### Name-Value Arguments

Example: scale='log10'

Scale to visualize the charge distribution on the surface of the PCB component, specified as a string or a character vector. The string values are either 'linear', 'log', or 'log10' or as a function. You can specify any mathematical function such as log, log10, cos, or sin.

Data Types: char | function_handle

Excitation using as voltage source of N-ports to excite an N-port RF PCB component, specified a string or a function handle.

Data Types: string | function_handle

## Output Arguments

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Complex charges, returned as a 1-by-n vector in C/m. This value is calculated on every triangle mesh or every dielectric tetrahedron face on the surface of a PCB component.

Cartesian coordinates representing the center of each triangle in the mesh, returned as a 3-by-n real matrix.

## Version History

Introduced in R2021b