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## Difference between L network Pi network T network antenna tuner type

This page compares L network antenna tuner vs Pi network antenna tuner vs T network antenna tuner and mentions difference between L network Pi network T network antenna tuner types.

Following are the characteristics of ideal tuner circuit.
➤It can transform high impedance to low impedance and vice versa.
➤It can eliminate or minimize any reactance present at the input and present pure resistive component as load to the transmitter.
➤It helps in matching balanced line and unbalanced line.

### L network antenna tuner

• The figure-1 depicts L-network antenna tuner type.
• It consists of series inductor and parallel capacitor.
• It is used to match unbalanced high impedance antenna with low impedance rig.
• It has very good low pass charateristics.
• Following equations are used to calculate inductive reactance and capacitive reactance.

Inductive Reactance (XL) = [ (Ra * Rin) - Ra2 ]0.5 ...Equation-1
Capacitive Reactance (XC) = [ (Ra * Rin)/XL ] ...Equation-2
Where,
Rin = Input Impedance
Ra = Antenna Impedance

The L-network which has parallel capacitor first at the transmit side and then series inductor at antenna side is used to match unbalanced antenna having low impedance compare to output of transmitter.

### Pi network antenna tuner

• The figure-1 middle part depicts π-network antenna tuner type.
• It is used to match high impedance source to low impedance load.
• The circuit can be converted to L-network type by setting any one capacitor to value of zero. Hence it is called very versatile tuner circuit.

### T network antenna tuner

• The figure-1 depicts T-network antenna tuner type.
• As shown it consists of two variable capacitors in series with load and a variable inductor connected in parallel at the junction.
• This configuration has high pass characteristics.
• This circuit can be used for multi-band application with appropriate L and C values.