T Matching Network Calculator

T-Network Impedance Matching Estimator

Input Fields

Frequency

f

Hz

Operating frequency

Source Resistance

Rs

Ω

Real part of source impedance

Source Reactance

Xs

Ω

Imaginary part of source impedance

Load Resistance

Rl

Ω

Real part of load impedance

Load Reactance

Xl

Ω

Imaginary part of load impedance

Q Factor

Q

Quality factor of the matching network

Circuit DC Current

Pass DC CurrentBlock DC Current

CalculateReset

Calculate automaticallyIf enabled, the result will update automatically when you change any value.

Your Results

Capacitor (C)

Series Inductor (Ls)

Shunt Inductor (Ll)

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T Matching Network Formulas (Rs ≠ Rl)

$$\text{For } R_s < R_l:$$ $$Q = \sqrt{ \frac{R_l}{R_s} - 1 }$$ $$X_1 = R_s \cdot Q$$ $$X_2 = \frac{R_l}{Q}$$ $$\text{For } R_s > R_l:$$ $$Q = \sqrt{ \frac{R_s}{R_l} – 1 }$$ $$X_1 = R_l \cdot Q$$ $$X_2 = \frac{R_s}{Q}$$

Where:

• $$R_s$$ = source resistance (Ω)
• $$R_l$$ = load resistance (Ω)
• $$Q$$ = quality factor
• $$X_1$$ = series reactance (Ω)
• $$X_2$$ = shunt reactance (Ω)

The specific component type (capacitor or inductor) depends on frequency and desired filter behavior.

T Matching Network – Calculation Example

Given:

• $$R_s$$ = 25 Ω
• $$R_l$$ = 100 Ω

Calculation:

1. $$Q = \sqrt{ \frac{100}{25} – 1 } = \sqrt{4 – 1} = \sqrt{3} ≈ 1.732$$
2. $$X_1 = 25 \cdot 1.732 = 43.3~Ω$$
3. $$X_2 = \frac{100}{1.732} ≈ 57.7~Ω$$

The T matching network is commonly used in radio frequency and antenna systems to match differing source and load impedances using a low-pass, high-pass, or bandpass configuration. It consists of two series reactive elements and one shunt reactive element. The values depend on whether the source resistance is lower or higher than the load resistance. Proper matching ensures maximum power transfer and minimizes signal reflection.