L-match networks are used to modify equipment input or output impedance, on a fixed frequency. The goal is to make the equipment look like 50ohm (or 75 or other) resistor. Often radio amateurs use L-match to modify antenna impedance in order to get optimal power tranfer between cable and antenna, SWR=1.

Impedance may need to be increased or decreased. L-match may be of low-pass- or high-pass-type. There might be a serial reactance with the resistance, which shall be taken into account. That's why four different configurations are needed and formulas for them are a bit different. I have done separate pages for each of them:

**❶ Increase resistance, low-pass type.** If the load impedance includes inductive reactance,
this model is the best. The reactance can be part of needed inductance and only smaller additional
reactance is needed. If the load inductance is bigger than needed for the L-match, a serial capacitor is added.

**❷ Increase resistance, high pass type.** If the load impedance includes capacitive reactance,
this model is the best. The reactance can be part of needed capacitance and only smaller additional
reactance is needed. If the load capacitance is bigger than needed for the L-match, a serial coil is added.

**❸ Decrease resistance, low pass type.** If the load impedance includes reactance, it will be first
eliminated with opposite reactance, inductive with capacitive and vice versa. In this respect LP and HP versions are similar.
Reasons outside of passband dictate, which one is most suitable: DC-blocking, frequency response further away, or so.

**❹ Decrease resistance, high pass type.** If the load impedance includes reactance, it will be first
eliminated with opposite reactance, inductive with capacitive and vice versa. In this respect LP and HP versions are similar.
Reasons outside of passband dictate, which one is most suitable: DC-blocking, frequency response further away, or so.

Altenatives to L-match networks are PI- and T-networks. Calculators for them are not shown here.